Street Code

01I saw this on the street. What is it?

The short version: Search or browse everything in this guide by what it looks like, not by what it is called. Type what you saw - "blue paint", "green hydrant cap", "triangle manhole", "bumpy yellow tiles", "blue light on the signal" - and jump straight to the explanation. The decoders below turn the street's color codes into plain words.

The street's color codes at a glance

The same handful of colors mean different things depending on what they are painted on. Pick a system to decode it. The full explanations live in sections such as utility paint and hydrant colors.

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02What the spray paint on the street means

The short version: Bright paint dashes, arrows and letters on pavement or grass are almost always locate marks: a utility's locator has shown roughly where a buried line runs because someone is about to dig. In the US, the color tells you the kind of utility (red electric, yellow gas, orange communications, blue drinking water, green sewer, purple reclaimed water, pink survey, white proposed dig), and the letters tell you who owns it. The marks show an approximate path, not an exact one, so excavators hand-dig in a band on each side. In the US, anyone planning to dig, even for a mailbox post, contacts 811 first (Dig Safe in Massachusetts, Maine, New Hampshire, Rhode Island and Vermont).

What do the colors mean?

What you see: Short dashes, lines and letters in red, yellow, orange, blue, green, purple, pink or white, often several colors in one spot.

Each color stands for a type of buried facility under the APWA uniform color code. The Common Ground Alliance (CGA), the US damage-prevention body, recommends in its Best Practices (Version 20.0) that the APWA code, referenced as ANSI Z535.1, be adopted nationwide for marking dig sites and buried facilities, while leaving any state free to specify other colors.⁴⁵ ANSI publishes the colors as the "American National Standard for Safety Colors."⁶

This code is for buried utilities. Painted traffic lines follow a separate system, covered in road lines, and pink survey paint is explained with survey marks.

The color only warns of the type of hazard.⁶ It does not say who owns the line, how deep it is or how big it is; that is what the letters are for. Paint on a lawn looks alarming, but locators use flags or a special marking paint, and neither does long-term harm to grass.⁷

What do the letters next to the paint mean?

What you see: Letters such as "W", "G", "E", "FO" or "TEL", or a company name, in the same color as the dashes, sometimes with sizes like 12" STL.

The letters identify the owner and the facility. CGA recommends a fixed order: company identifier, then facility type, then construction, then material, written with slashes, for example "TELCO/TEL/FO/PLA" (a telecommunications company's fiber optic line in plastic conduit).⁸ One state one-call center's guide says the company name must always appear at the top or to the left.⁶

Source for all three rows: CGA's Common Abbreviations.⁸ Field crews often write "CATV" for cable TV, but CGA's list uses "TV."

Owner letter codes are local. In Virginia, for example, the notification center assigns each operator its letters, and the state manual adds "RF" for buried RFID markers, "HDD" for a line installed by horizontal directional drilling, and a green "T" where a sewer lateral meets the main.⁹

What does "NO" spray-painted on the ground mean?

What you see: "NO" followed by a company name or code, such as "NO TELCO," painted in a utility color, or a clear plastic flag with writing on it.

This is a no-conflict mark: the owner checked and has nothing in the way of the planned dig. CGA's guidance is "NO" plus the owner's identifier in that owner's APWA color. Companies that run more than one kind of system add a facility code, as in "NO GASCO/G/D" (no gas distribution line here).¹⁰ A slash through a letter carries the same meaning in some states.⁶ CGA also describes clear translucent "No Conflict" flags carrying the owner's identifier, phone number, a space for the ticket number and the date.¹⁰

A no-conflict mark speaks only for that owner. Another company's line can still be there.

What do the arrows, H-shapes and numbers mean?

What you see: Dashes with arrowheads, an "H" drawn across a pair of lines, numbers with inch marks, or "OFF" with a distance.

CGA describes locate marks as roughly 12 to 18 in. long (30 to 45 cm) and 1 in. (2.5 cm) wide, spaced about 4 to 50 ft (1.2 to 15 m) apart.¹⁰ State manuals vary: Virginia calls for marks about 8 to 10 in. long and 1 to 2 in. wide, no more than 20 ft (6 m) apart, with at least three marks per line.⁹

The shapes, per CGA's field delineation guidelines:¹⁰

• Single line over the center. A single facility is marked over its approximate center.
• "H" shape. A wide facility can be marked at its two outside edges, joined by a bar, so the mark looks like an H.
• Count and size. Several facilities together show the count and size, e.g. "4/4" PLA" for four 4-inch plastic ducts. A corridor of unknown count shows its width, e.g. "12" CDR."
• Arrow. Shows a change of direction or a lateral branching off.
• Offset. An offset mark sits to one side of the line with a direction and distance and the label "OFF," used when a mark cannot go directly over the facility.
• Casings. Noted in words, e.g. "6 in. plastic in 12 in. steel."

Virginia's manual adds that arrows can show a line continuing beyond the ticket area, that offset arrows carry the distance on the right and size, material and operator letters on the left, and that a "hump" symbol shows two lines crossing without saying which is on top.⁹ Gopher State One Call's guide shows a diamond for conduit.⁶

What are the little flags and plastic whiskers in my yard?

What you see: Small colored plastic flags on wire stems, wooden stakes, or tufts of colored plastic bristles poking out of grass or gravel.

These are locate marks in another form. CGA lists paint, flags, stakes and whiskers, or a combination, as marking methods.¹⁰ Virginia's manual calls for flags, stakes or whiskers where paint will not last or will not show: high-traffic areas, landscaping, snow and loose soil.⁹ The colors follow the same code as paint. Whiskers are tufts of colored plastic strands driven into the ground; CGA names them as a method without describing them further.

Leave them in place until the work is done. Locators and excavators rely on them, and a pulled flag can mean a missed line.

What does white paint mean before digging?

What you see: White dashes, dots, an outline or white flags around a patch of ground, sometimes with a contractor's initials, before any colored marks appear.

White is the digger's paint, not the utility's. White-lining (or premarking) outlines where an excavator plans to dig, so locators know which lines to look for. CGA Practice 5-2 describes white dashes about 6 to 12 in. long and 1 in. wide, about 4 to 50 ft apart; 1 in. dots for arcs; a continuous line around a single-point site; centerline arrows for trenching or boring; and white stakes, flags or whiskers carrying the excavator's identifier. A single white center stake can mark a site within a 50 ft (15 m) radius.¹¹ Virginia's white lining shows the width in feet on either side of a centerline.⁹

In Massachusetts, premarking with white paint or stakes is required before any excavation, even on private property, and before calling Dig Safe.² Dig Safe adds that digging outside the premarked area needs another ticket.¹²

How close to the marks can you dig?

What you see: Nothing painted, but the crew puts down the excavator and picks up shovels or a vacuum hose near the marks.

The marks are approximate, so there is a no-machine band around them called the tolerance zone. CGA Practice 5-19 defines it as "the width of the facility plus 18 in. on either side of the outside edge of the underground facility on a horizontal plane," and says it is not meant to override state rules that specify more than 18 in.¹³ That is about 46 cm on each side.

Dig Safe tells excavators to use non-mechanical methods within 18 inches of a marked facility.¹² Massachusetts treats marks that are off by more than 18 inches as inaccurate and says to hand-dig near them.² Some states use a wider zone.

New York is one of them: National Grid's contractor guidance gives New York's zone as "one-half of the known diameter plus 24 inches on either side of the designated centerline," against 18 inches on either side of the marks in Massachusetts and Rhode Island.¹⁴ In Texas, a 2017 federal summary of state law lists 18 inches for intrastate pipelines.¹⁵

How long do the marks last?

What you see: Faded marks, or fresh marks painted over older ones in the same place.

Paint fades on its own schedule, but the legal life of the marks is set by the ticket, the record of a dig request. In Massachusetts a ticket is valid for 30 days and must be renewed at least 72 business hours before it expires; utilities must mark by the time the ticket becomes valid, re-mark within 24 hours when asked, and the marks must be kept clearly visible.²

Ticket life differs even among the five Dig Safe states: 30 days in Massachusetts, New Hampshire and Vermont, 60 days in Maine, and no expiry in Rhode Island as long as the marks are maintained.¹² So a fresh coat over old paint usually means a new or renewed ticket.

What is 811?

What you see: "Call 811 before you dig" on utility trucks, door hangers, pipeline markers and paint cans.

811 is the US three-digit number that routes callers to their state's one-call center, the organization that takes dig notices and passes them to member utilities. The Pipeline Safety Improvement Act of 2002 provided the basis; the FCC designated 811 for state one-call systems in an order released March 14, 2005, published in the Federal Register on April 13, 2005, and gave phone carriers two years from publication to implement it.¹ The number launched nationally on May 1, 2007, at a press conference with CGA, Transportation Secretary Mary Peters and the FCC, where officials cited "more than one unintentional hit per minute every day, every year."¹⁶

What counts as digging is broad. Massachusetts includes grading, backfilling, demolition and even installing a mailbox, and requires notice at least 72 business hours ahead, not counting weekends and holidays.² Member utilities mark only the facilities they own or maintain.¹² A line the homeowner owns, such as a cable out to a garage, falls outside that.

How often do people hit buried lines?

What you see: Nothing on the street, but this is the reason the paint is there.

CGA's annual Damage Information Reporting Tool (DIRT) report counts reported damage to buried facilities. For 2024 it counted 196,977 unique damage reports, and the CGA Index rose from 94.0 in 2023 to 96.7 in 2024, leaving the industry off track for its "50-in-5" goal.¹⁷

The leading root causes in 2024:¹⁷

The top 10 causes made up 85 percent of damages. Across eight 811 centers, excavators had an average 38 percent chance of not starting on time because locate responses were incomplete.¹⁷ Roughly one damage in four came from a dig where nobody called.

For what happens after a hit on a gas main, see the sister guide's section on gas and steam.

In Boston

In Boston, as in the rest of Massachusetts and in Maine, New Hampshire, Rhode Island and Vermont, the one-call center is Dig Safe.¹² The state rules, in short:²

• White-line the dig area first, even on private property.
• Contact Dig Safe (811, or (888) 344-7233) at least 72 business hours before digging.
• The ticket lasts 30 days; renew it at least 72 business hours before it runs out.
• Hand-dig near the marks; marks should be within 18 inches of the facility.
• Penalties run up to $200,000 per violation for natural gas lines; for other facilities, $1,000 for a first offense and up to $10,000 for later offenses within 12 months. The Department of Public Utilities' Pipeline Safety Division enforces the law under G.L. c. 82 sections 40-40E and 220 CMR 99.00.

Massachusetts does not require municipal water and sewer departments to join Dig Safe.² That matters for blue and green marks: a city water line may not be marked through a Dig Safe ticket unless the department is a member. The sister guide covers how the city's water system is laid out.

The Boston Water and Sewer Commission runs its own water and sewer mark-out request form, separate from a Dig Safe ticket. As of 2026 its page asks for white premarking first, at least three business days' notice and no more than 30 days, recommends that the contractor rather than the owner make the request, and calls for non-mechanical digging within 18 inches of its marks.¹⁸

Dig Safe's excavator manual asks that each owner be identified by initials or company name in letters 6 in. high at the start and end of a locate and every 100 ft on long ones.¹⁹ For the rest of the city's street hardware, see Boston.

Elsewhere in the world

Canada. There is no single national number, and 811 is not Canada's national number. Each province runs a center: Alberta One Call, BC One Call, Manitoba's Click Before You Dig MB, Ontario Dig Authority, Sask 1st Call, and Info-Excavation for Quebec, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland, with clickbeforeyoudig.com as the national portal.²⁰

United Kingdom. The UK works from plans more than from paint. LinesearchbeforeUdig (LSBUD) is a free online service where diggers search the networks of over 150 asset owners covering electricity, gas, high-pressure fuel, water and fiber; not every owner is a member, so users must contact the rest themselves.²¹ The Health and Safety Executive's guidance HSG47, "Avoiding danger from underground services" (third edition, 2014), makes locating and identifying buried services part of a safe system of work.²² Professional utility surveys follow BSI PAS 128, first published in 2014 and revised by ICE and BSI in 2022; it covers detecting, verifying and locating active, abandoned and unknown utilities, with quality levels based on survey type, location accuracy, post-processing and supporting data.²³

Australia. Before You Dig Australia (BYDA), formerly Dial Before You Dig, is a free national referral service: a web enquiry goes to asset owners near the site, who reply with plans.²⁴ BYDA also runs "Look Up and Live" for overhead power lines.²⁵ BYDA sends plans; any marks on the ground come from whoever does the locating.

Paint colors abroad. Canadian practice largely follows the US code: the City of Windsor, Ontario, says it and local utilities use the APWA uniform color code, with the same eight colors.²⁶ According to the design publication 99% Invisible, the UK shares many US colors but uses green for telecom rather than sewers, and Australia has its own system with orange for electricity, white for communications and cream for sewage.²⁷

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03Survey marks, benchmarks and the nails in the curb

The short version: The round metal disk set in a curb or bridge, the nail in the asphalt and the capped rod at a property corner are all survey marks: fixed points that surveyors measure from. US government disks, mostly from the National Geodetic Survey and its predecessor the Coast and Geodetic Survey, record a precise position or elevation, and each one in the NGS database has a public datasheet you can look up. In the US, willfully defacing, changing or removing a government survey mark is a federal offense. In Britain the equivalent is the Ordnance Survey's chiseled "crow's foot" arrow and its metal flush brackets.

What is the round brass disk in the sidewalk?

What you see: A coin-like brass or aluminum disk, about the size of a drink coaster, set flush in a curb, sidewalk, bridge abutment or rock, stamped with letters, numbers, maybe a triangle or an arrow, and sometimes a warning about a fine.

It is a survey mark. Classic US benchmark disks are brass or aluminum, about 3.5 in. (9 cm) across, set in rock or concrete, and usually stamped with a station name, a year, sometimes an elevation, and the agency that set it. The US Geological Survey gives the example "C9 1923 7337.580": station C9, set by the US Coast and Geodetic Survey in 1923, at an elevation of 7,337.580 ft.²⁸

Not every mark is a disk. Some are rods driven until they will go no deeper, under hinged covers; crosses or squares are occasionally chiseled into rock.²⁸ NOAA lists disks, stainless steel rods, drill holes and even landmarks like water towers as survey marks, and counts more than 1,200,000 marks in the US.²⁹

Federal disks are the best known, but state transportation departments, counties and cities set their own, with their own stamping. Whoever set it, the point is the same: a fixed spot whose position or height was measured carefully once, so that later surveys can start from it instead of from scratch.

What do the triangle and arrow on a survey disk mean?

What you see: A disk with a small triangle in the center, or one with an arrow stamped across it, often a few feet from another disk.

The design tells you what the mark is for.

Reference marks exist because main stations get buried, paved over or knocked loose. If you find a disk with an arrow, the station it points to may be a short distance away along that line.

NGS's own manual, Geodetic Bench Marks (NOAA Manual NOS NGS 1, 1978), describes the standard disk as brass or bronze, about 9 cm across, with a slightly domed top to support the foot of a leveling rod and a shank about 7.5 cm long underneath. The setter stamps the mark's designation and year on top with 3/16 in. (4.75 mm) steel dies, and the agency's recessed logo and legend identify the mark and tell the finder where to get its data.³¹

Is it illegal to remove a survey marker?

What you see: Disk text warning of a fine, such as "250-dollar fine or imprisonment."

Yes for government marks in the US. Some older disks carry that warning in the metal itself.²⁸ Federal law, 18 U.S.C. 1858, penalizes anyone who "willfully defaces, changes, or removes any monument or bench mark of any Government survey."³⁰ NOAA's advice to hunters is never to disturb a benchmark.²⁹ If a mark is in the way of construction, the agency that owns it is the one to contact; the mark recovery process below is how you tell NGS.

How do I look up a survey benchmark?

What you see: A disk you want to identify, or a curiosity about what is near your street.

Every mark in the NGS database has a six-character PID (Permanent Identifier).³² Look up the PID and you get the mark's datasheet: its coordinates, its elevation where known, and a "Station Description" giving directions to it from nearby landmarks.²⁹

To work backward from a disk on the ground, note the stamped name and year, the agency and where it sits, then search the NGS records for that name in your area. NOAA's survey mark hunting activity walks through the process for beginners.²⁹

Anyone can report what they find. NGS takes recoveries from the public through its Mark Recovery Form, using the mark's PID; individuals enter agency code "M" and agency "INDIV," and questions go to ngs.mark.updates@noaa.gov.³³ A report that a mark is still there, in good shape, or destroyed is useful to the surveyors who depend on it.

The sources disagree on how many marks there are. NGS says it keeps records of more than 800,000 survey marks;³³ Wikipedia gives about 740,000 benchmarks in the NGS database;³² NOAA's activity guide counts more than 1,200,000 survey marks of all kinds in the US.²⁹ The figures likely count different things, but none of the sources reconciles them.

Who goes looking for benchmarks?

What you see: Someone crouched over a curb with a phone, a printout and a brush.

Benchmarking is a hobby: finding survey marks from their datasheets, photographing them and reporting their condition. Geocaching.com hosted a benchmarking section until 2023; its retirement notes are dated October 17, 2022.³² NGS's mark recovery form remains the official way to report a find.³³ In the UK, hobbyists hunt trig pillars, of which the T:UK site lists 6,550, along with benchmarks.³²

The etiquette is the same everywhere: look, photograph, report, and leave the mark exactly as you found it.²⁹

What is a PK nail in the road?

What you see: A small, flat nail head in asphalt, sometimes with a metal washer under it, often circled or flagged with pink or orange paint.

These are surveyors' nails, driven as temporary control or reference points for a project: the spot a crew sets its instrument over, or a reference tied to a corner. Surveyors treat the PK nail and the MAG nail as the standard pavement nails; alternatives include Ramset nail-and-washer combinations, concrete nails and spikes, chosen partly for how easily a metal detector picks them up.³⁴

What is the X or square chiseled into the curb?

What you see: A small cross or square cut into a granite or concrete curb, sometimes with a dot of paint or a number beside it.

A chiseled cross or square is a recognized survey mark form; the USGS notes such marks cut into rock, though rarely.²⁸ On a curb, a cut cross can serve as a durable control point or a reference for a nearby property corner, because a curb is heavy, hard to move and easy to find again. Without a record from whoever cut it, the meaning of any one cross is hard to tell from the street.

Some local standards make the curb cross the official corner mark. Yolo County, California's 2008 improvement standards for survey monuments require that "cut crosses in the concrete curb or sidewalk shall be used instead of iron bar or pipe bar at the front of the property."³⁵

What is the metal rod with a cap at my property corner?

What you see: A steel rod or pipe flush with the ground, often topped with a colored plastic or aluminum cap stamped with a name and number, sometimes with a wooden stake and bright tape beside it.

It is a property pin, a boundary monument set by a licensed land surveyor. The cap identifies who set it. Gig Harbor, Washington, for example, required in a 1986 ordinance that lot corners be staked with "an iron pin topped with a plastic cap marked with the Registered Land Surveyor's name and license number."³⁶ Some surveyors use different sizes of rebar for boundary monuments and for control points to avoid confusing the two.³⁴

Each state sets its own monument rules. If you are building a fence or a shed near a line, a pin is useful evidence, but the surveyor whose number is on the cap, or the recorded plan, is the authority on where the line runs. Pins sit below the surface where digging happens, so the rule in the paint section applies: in the US, contact 811 before you dig (Dig Safe in Massachusetts).

What does pink spray paint on the road mean?

What you see: Hot pink dots, crosses or numbers on pavement, or pink flagging tape on a stake.

Under the APWA color code used for locate marks, pink means temporary survey marks, and also unidentified facilities.⁶ Pink on its own therefore often means a surveyor was there, not a utility locator. The same color is used when a locator finds something buried that it cannot identify, so pink next to dashes and arrows reads differently from a pink circle around a nail.

In Boston

The NGS lookup, the federal law on government marks and the pink-paint convention all apply in Boston as anywhere in the US. Massachusetts requires white premarking before any dig, so in Boston a survey crew's pink can share the pavement with a contractor's white.² The sister guide's section on roads covers the street reconstruction that survey crews are usually measuring for.

Federal disks are easy to find downtown. NOAA's bench mark sheet for its Boston tide station (8443970, published 2018) lists a disk stamped "3970 C 1991" in the granite bulkhead cap by the southwest corner of the Northern Avenue Bridge, a Coast and Geodetic Survey disk stamped "FED 2 ELEV 20.186" in the bottom step of the Devonshire Street entrance of the US Post Office, and an NGS disk stamped "3970 D 2000" in the seawall cap at Christopher Columbus Park.³⁷

Elsewhere in the world

What is the arrow carved into old buildings in England?

What you see: A horizontal line cut into a wall, church, bridge or gatepost, with a three-line arrow beneath it pointing up at the line.

It is an Ordnance Survey cut benchmark, marking a height above Ordnance Datum Newlyn.³⁸ Cut marks are chiseled into stone, brick or wood as a horizontal leveling line over a three-line arrow, usually pointing up.³⁹ The arrow is the broad arrow, nicknamed the "crow's foot," which became the mark of the Board of Ordnance by 1597.⁴⁰ Cut marks are "the commonest and least highly-ranked grade" of benchmark.⁴¹

Variants include rivets (cut marks on horizontal surfaces with a brass rivet), bolts engraved "OSBM," and pivots made to take a 16 mm ball bearing.³⁹

About 500,000 of these "lower order" benchmarks remain, but only about 190 fundamental benchmarks are still maintained. Ordnance Survey says the rest have not been maintained for decades (the page gives both 30 and 40-plus years) and that their heights "should not be relied upon." The full list is searchable online and downloadable as an archive under the Open Government Licence.³⁸ The bench-marks.org.uk site maps them too.⁴¹

What is a flush bracket on a wall?

What you see: A rectangular metal plate about 6 by 3 in. (15 by 7.5 cm) on a wall or a concrete trig pillar, cast with "OS," the broad arrow and a number like "S1755."

A flush bracket is a higher-order OS benchmark. One example reads "OS," the broad arrow and "BM S1755," with two square sockets above the arrow that once held a leveling staff support.⁴⁰ Flush brackets rank below fundamental benchmarks, and trig pillars usually carry one.⁴¹ Their numbers date them: plain numbers 1 to 3000 were used from 1912 to 1921, the S prefix from the 1920s and the G prefix from 1936. Brackets not on pillars are known as NPFBs (non-pillar flush brackets).³⁹

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04Fire hydrants: colors, caps and the blue dot in the road

The short version: A fire hydrant is a valve on the water main; in the US, firefighters open it with a five-sided wrench. A voluntary US recommendation, NFPA 291, says the top color shows how much water the hydrant can deliver and the body color shows who supplies it, but most cities do not follow it exactly, so treat color as a hint, not a promise.⁴² The blue road reflector, the flag on a stick and the painted curb help a fire crew find the hydrant fast and connect to it without a car in the way. In much of the rest of the world the hydrant is underground, and what you see instead is a sign telling firefighters where to find its cover.⁴³

What do the colors on a fire hydrant mean?

What you see: A knee-high cast iron post at the curb, usually yellow, red or silver, with a domed top and caps in a different color.

The domed top is the bonnet. Under NFPA 291, the National Fire Protection Association's recommended practice for flow testing and marking hydrants, the bonnet and caps are painted by flow class, measured at 20 psi residual pressure (the pressure left in the main while the hydrant is flowing).⁴² Flow is given in GPM, gallons per minute.

Source for the classes: ⁴²

The body, or barrel, says what kind of system feeds the hydrant:⁴²

Black means trouble. The Mueller summary says a hydrant that is permanently out of service should be painted black, marked or removed, and a hydrant that is temporarily inoperable should be wrapped and marked.⁴² Wikipedia adds that black can also mark a hydrant at the end of a system, and that many places use a white or purple top for non-potable water.⁴³

The standard itself is paywalled. The classes here come from a manufacturer's white paper and from Wikipedia, which agree.

Why doesn't my city follow the color code?

What you see: Hydrants that are all red, all silver, or painted in colors that match no chart.

Because nobody has to. In the US there is "no federally mandated color coding of fire hydrants," and since NFPA 291 is voluntary, Mueller notes "it is not followed by a majority of municipalities."⁴² Some examples of how cities go their own way:

• Chicago paints hydrant bodies red to show city ownership. The color on the top flange shows the size of the main, not the flow: white for 6-inch (150 mm) or smaller mains, which are being replaced; red for 8-inch, the most common; yellow for 12 to 16-inch; blue for mains over 16 inches. As of 2017 the city had 48,209 hydrants, about 300 feet (90 m) apart.⁴⁴
• New York City hydrants are "often painted black or silver," according to a mapping company's blog, which says color is not a reliable flow indicator there.⁴⁵ No official NYC source confirmed this.
• Toronto and Vancouver usually have yellow bodies with NFPA-style colored tops, per the same blog.⁴⁵
• Ottawa paints a special scheme on hydrants so corroded inside that firefighters should skip them.⁴³

If you want to know what your local colors mean, the water utility is the place to ask.

What are the caps and outlets on a hydrant?

What you see: Two smaller capped outlets on the sides and one larger one facing the street, each with a cap on a chain.

A typical US dry-barrel hydrant has two smaller hose outlets and one larger outlet called the steamer or pumper connection.⁴³ A pumper engine takes its supply from that big outlet and boosts the pressure for the hose lines. Some hydrants have a Storz fitting on the big outlet instead of a threaded one.⁴³ Where it faces the street, the engine's intake hose gets a short, straight run.

Dry barrel or wet barrel: why some hydrants have one nut on top and others have three on the side

What you see: In cold places, one operating nut on top of the hydrant. In warm places such as California or Hawaii, a separate valve stem beside each outlet.

In a dry-barrel hydrant, the main valve sits underground below the frost line. A long rod runs up through the barrel to the operating nut on top, and when the valve closes, a drain opens and the barrel empties so it cannot freeze. One stem controls all the outlets at once.⁴³

A wet-barrel hydrant stays full of water. Its valves are in the above-ground part, so each outlet can be opened separately. These are used in warm areas.⁴³ The trade-off is plain: a wet barrel would crack in a hard freeze, and a dry barrel gives up separate control of each outlet in exchange for surviving winter.

In a city that freezes every winter, like Boston, the dry-barrel design is the one that makes sense.

Why is the nut on a fire hydrant a pentagon?

What you see: The nut on top and the nuts on the caps have five sides instead of six.

A pentagon nut does not fit an ordinary wrench or socket, which are made for square and hex shapes. The shape was "chosen specifically to prevent unauthorized access," and the matching tool is called a hydrant wrench, fire wrench or pentagon wrench.⁴⁶ Wikipedia describes the same tool as a large wrench with a pentagonal socket and gives the reason: people who open hydrants without permission waste water and reduce the pressure firefighters need.⁴³

That pressure loss is the serious part: an open hydrant on a hot day leaves less pressure for a fire nearby. If you see a hydrant running with nobody from the city around, report it to the water utility or the city's non-emergency line (BOS:311 in Boston) rather than trying to close it.

What is the tall pole sticking out of a hydrant?

What you see: A thin rod, often red or orange, sometimes with a flag, reflector or spring at the base, rising well above the top of a hydrant.

It is a snow marker. In snowy areas, tall signs or flags help crews find hydrants buried by plows and drifts, and in rural areas tall narrow posts in bright colors such as red are attached to the hydrant itself.⁴³ The marker is there for the fire crew; it does not change how the hydrant works.

Markers help crews find a hydrant, but someone still has to dig it out. Boston, Chicago, Providence and Anchorage adopted Code for America's Adopt-a-Hydrant program, in which volunteers shovel hydrants out after storms.⁴³ Boston launched its version in January 2011: residents claim a hydrant on a map, give it a name and commit to clearing it after snowstorms.⁴⁷ If you clear one, clear the snow around it and a path to the street, and leave the hydrant itself alone.

The Boston Water and Sewer Commission makes the same request in its winter customer newsletter: "Shovel out fire hydrants near your home to help the fire department in case of emergency."⁴⁸

What does a blue reflector in the road mean?

What you see: A small blue reflective bump glued to the pavement, usually near the center line, roughly across from a hydrant.

It is a raised pavement marker (RPM), sometimes called a cat's eye (the white and yellow kind is covered in road lines), placed so a fire engine driver can spot the hydrant from far down the block at night. In the US, the federal Manual on Uniform Traffic Control Devices (MUTCD) defines a raised pavement marker as a device that can be used, among other things, "to mark the position of a fire hydrant." A 2005 FHWA official interpretation quotes that definition from the 2003 edition.⁴⁹ The manual's support text, as adopted in Delaware's version, says: "Blue raised pavement markers are sometimes used in the roadway to help emergency personnel locate fire hydrants."⁵⁰

So it is optional local practice, not a federal requirement. Some cities write it into their standards: Fremont, California's hydrant detail calls for blue raised reflective markers "inline with the hydrant in the pavement."⁵¹

You mostly see them where it does not snow. Snowplow blades scrape raised markers off the road, so blue reflectors are typical in US areas without winter snow.⁴³ That helps explain why they turn up more in Sun Belt suburbs than on Boston streets. Australia uses them too, placed beside the center line on the hydrant's side of the road.⁴³

In the current federal MUTCD, the 11th edition (2023), the general raised pavement marker section, 3B.14, says a marker's color must match the line it guides, allows red on the side facing wrong-way traffic, and does not mention blue.³

How far do you have to park from a fire hydrant?

What you see: Sometimes a yellow or red painted curb by the hydrant. Often nothing at all. The rule applies either way.

Parking distance is set in law, and it differs from place to place. Curb paint is a reminder where it exists, not the rule itself:

The reason is room to work. The pumper needs to pull up and run a short, fat supply hose from the steamer outlet, and a car in the way forces a longer lay or a hose through the car. Firefighters may run a hose through a parked car's windows.⁴³

In Boston, as of October 2026, a hydrant ticket is $100, with a $33 late penalty, the same as parking in a fire lane.⁵⁶

Why do people call it a fireplug?

What you see: The word "fireplug" in old books and local speech, and the occasional antique hydrant kept as a curiosity.

Early water mains were hollow wooden logs, used from the 16th century. To fight a fire, people dug down, bored a hole in the main, let the water flood out, then hammered a wooden plug into the hole afterward. The plug gave us "fireplug."⁴³⁵⁷

Underground hydrants were in use in Europe and Asia from at least the 18th century; the above-ground pillar hydrant is a 19th-century invention.⁴³ Who invented it is unsettled. Frederick Graff of Philadelphia (1775-1847), engineer of the Centre Square water works from 1805, is traditionally credited with the modern hydrant in 1801, but a patent "cannot be confirmed" because records were lost in the 1836 Patent Office fire.⁵⁸ The main Wikipedia hydrant article flags the 1801 claim as dubious, and lists surviving early patents from Jorden (1838) and Holly (1869).⁴³ The Fire Museum of Canada notes that other sources credit George Smith, a New York firefighter, around 1817.⁵⁷ The honest answer is that sources disagree.

In Boston

What you see: Red and yellow hydrants side by side across the city, some with names claimed online through Adopt-a-Hydrant.

The Boston Water and Sewer Commission (BWSC) maintains the city's hydrants and publishes their locations on Analyze Boston, the city's open data site.⁵⁹ There are more than 13,000 public hydrants.⁴⁷ Repainting requests made through BOS:311 go to BWSC; one hydrant at 989 Commonwealth Avenue was repainted on October 4, 2022, after a report.⁶⁰

What the red and yellow mean in Boston is an open question. On a 2013 Universal Hub thread, readers offered competing explanations, from different pressure systems to no meaning at all, and none was confirmed.⁶¹

For how the water gets to the hydrant in the first place, see How a City Works: water. The red boxes on Boston's street corners are a separate system, covered in fire hardware.

Elsewhere in the world: the UK's yellow H plate

What you see: A small yellow plate with a big black "H" and two numbers, on a wall, fence, lamp post or short post. Nearby, a small yellow-painted cover in the pavement or road.

UK hydrants are underground, and Japan, Spain and Russia also put hydrants under heavy metal covers.⁴³ The hydrant marker plate tells firefighters where the cover is. The number above the bar is the water main diameter in millimeters; the number below is the distance from the plate to the hydrant cover in meters.⁶² A plate reading 100 over 4 means a 100 mm main, with the hydrant 4 m away. Older plates may give inches and feet.⁶³ The pit cover itself is "typically painted yellow" and usually marked "FH," and some plates add an arrow pointing to the hydrant.⁶³

Black on yellow was chosen by the National Fire Service in World War II because it reads well in all light. Before the war, London-area plates were white or blue, and the shape carried meaning: a diamond meant the hydrant was directly in front of the plate, a square meant across the road.⁶² The plates are specified by BS 3251:1976, "Indicator plates for fire hydrants and emergency water supplies," still current.⁶⁴ Ireland uses similar plates; Finland uses blue ones.⁴³

Elsewhere in the world: Germany's red-bordered hydrant sign

What you see: A white rectangular sign with a red border, a large T-shaped line, the letter H and several numbers, on a wall or post.

The German Hydrantenschild locates a hydrant by measurement. A red border means a fire hydrant; blue borders mark other water fittings, and a yellow background marks gas fittings.⁴³ "H" (older signs say "UH") means an underground hydrant and "OH" an above-ground one, followed by the pipe diameter in millimeters; 80 is a small size found in residential areas. The numbers left and right of the T give the sideways offset, and the number below gives the distance in front of the sign, in meters to 0.1 m precision. A negative number means behind the sign.⁴³

Elsewhere in the world: Japan's 消火栓 lids and signs

What you see: A round or square metal lid in the road, often marked 消火栓, and a red sign with white characters on a pole nearby.

消火栓 (shōkasen) means fire hydrant: 消火 "extinguishing fire" plus 栓 "plug or valve." Japanese hydrants have red-and-white signs.⁶⁵ Most street hydrants are underground under a heavy lid,⁴³ and they may be marked by a location sign or by markings on the road surface or the lid.⁵⁵ For outdoor hydrants on building sites, Kyoto's fire code guide requires a 消火栓 sign at least 100 by 300 mm, white characters on red.⁶⁶ The 5 m no-parking rule applies to the hydrant and to the designated fire water source sign, and to fire cistern intakes too.⁵⁴

Saitama City, for example, puts a sign near each hydrant, and where there is no sign or the hydrant is hard to spot, it paints yellow lines on the road surface.⁶⁷

Elsewhere in the world: Australia's blue cat's eyes and hydrant plates

What you see: A blue reflector near the center line, a painted white or yellow triangle or arrow on the road, and a small plate on a post with letters and numbers.

Most Australian hydrants are underground valves, so the markings do the finding. Blue road markers beside the center line show which side of the road the hydrant is on and can be seen for several hundred meters at night. Painted white or yellow triangles or arrows on the road also mark hydrants.⁴³

The plates use letter codes: H for a potable-water hydrant, RH for recycled water, P for a hydrant in the pathway, R for one in the roadway, plus the distance in meters and the main size in millimeters. Potable plates are white and recycled plates purple, and a black center line on the plate means the hydrant is across the road.⁴³ Practice varies by state. In Victoria, Fire Rescue Victoria uses above-ground L-type hydrants with Signal Red covers.⁴³

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05Red boxes, Siamese connections and the stuff on building walls

The short version: Most of the fire hardware on a building's street face helps a fire crew work fast: pump water into the building's pipes (the fire department connection), get through the door (the key box), see that the sprinkler supply is open (the indicator valve) and hear when sprinklers are flowing (the outdoor alarm bell). Red curbs and fire lane signs keep the way clear for the engine. In Boston, the red box on a post with a lamp above it is a working fire alarm telegraph box from a system the city switched on in 1852, and about 1,250 were still in service as of April 2026.⁶⁸⁶⁹ The gray meter with a bell-shaped device on the pipe is the gas service, and its small vent pipe needs to stay clear.⁷⁰

What is the pipe with two caps sticking out of a building?

What you see: One, two or more brass or chrome hose inlets with caps or plugs, sticking out of a building wall at about knee to chest height or on a pipe near the sidewalk, with a small sign above.

This is a fire department connection (FDC). It is an inlet, not an outlet: a fire engine hooks a hose to it and pumps water into the building's sprinkler system, its standpipes, or both. A standpipe is a vertical pipe inside a building with hose outlets on each floor, so firefighters can connect hoses upstairs instead of dragging them up from the street. The two-inlet version, a Y-shaped fitting that joins two hoses into one pipe, is widely nicknamed a Siamese connection. The nickname refers to conjoined twins, after the way the two inlets are joined into one pipe.⁷¹

A few specifics from the US NFPA standards:

• FDCs are normally pumped at 150 psi (about 10 bar). A sign stating the pressure is required only when the system needs more.⁷²
• NFPA 13's advisory annex places the connection 18 inches to 4 feet (0.45 to 1.2 m) above grade.⁷³
• NFPA 13D, the sprinkler standard for one- and two-family homes, has no FDC requirement, so houses with sprinklers usually do not have one.⁷²

The caps and plugs keep trash out of the inlets. Leave them on.

What does AUTOSPKR mean on a sign?

What you see: A metal plate or a raised ring around the inlet reading AUTOSPKR, STANDPIPE, or both.

AUTOSPKR is short for "automatic sprinkler." The sign tells the arriving crew what the inlet feeds, which matters because a sprinkler system and a standpipe system need different pumping. Under the NFPA standards, as summarized by the National Fire Sprinkler Association:⁷²

The letters are 1 inch (25 mm) high, on a plate or on the fitting ring. A generic "FDC" sign is not required by these standards, though many buildings have one.⁷²

NFPA 14 (2016) adds more for standpipes. A manual standpipe connection must also say "manual" and "wet" or "dry," where a dry standpipe is empty until the fire department fills it. If the system needs an inlet pressure different from the usual, the sign must state it. An FDC that serves more than one building must list the buildings it serves.⁷⁴ That last rule is why you sometimes see a plate naming a different address than the one it is bolted to.

What is the small black box by a building door?

What you see: A small, heavy steel box, usually black or bronze, bolted to the wall beside the main entrance at about head height, sometimes with a red reflective sticker.

It is a rapid-entry key box, best known by the brand name Knox-Box. Inside are the building's keys: ideally one master key, or else keys to the entrances, security gates, electrical and mechanical rooms and any elevator. The owner cannot open it. The local fire department holds the master key, and those department keys are locked in a device on the fire apparatus that releases them electronically, which keeps an audit trail of who took a key and when.⁷⁵ The point is to let firefighters in at 3 a.m. without breaking down a door, and to let them lock up again afterward.

Howard County, Maryland's guidance places the box 3 to 6 feet (0.9 to 1.8 m) above grade and within 6 feet of the main entrance.⁷⁵ The KnoxBox was developed in 1975 for fire departments. The Knox Company, based in Phoenix, says it is used by more than 14,000 fire departments, police and government agencies.⁷⁶

Whether a building needs one is up to the local fire department and code officials.

What is the post with OPEN or SHUT in front of a building?

What you see: A waist-high post near a building, often red or yellow, with a small window showing the word OPEN or SHUT and a wrench handle on top, held by a padlock, chain or wire seal. The wall version has the same window and handle bolted to the building wall.

This is a post indicator valve (PIV): the above-ground handle for an underground valve on the water supply to the building's sprinklers and wet standpipes. A target inside the window shows OPEN or SHUT; if you see part of each word, the valve is partly open.⁷⁷ An inspector, or a firefighter pulling up, can tell at a glance whether the sprinklers have water.

The wrench is locked to the post with a padlock or wire seal so no one shuts it by accident. Wire-sealed valves are inspected weekly, padlocked ones monthly, and valves with an electric tamper switch, a sensor that signals an alarm if the valve is moved off open, quarterly.⁷⁷ Under NFPA 13 (2022), the top of the post must be 32 to 40 inches (800 to 1,000 mm) above grade; wall versions are exempt from that height rule.⁷⁸

Before 2010, NFPA 24 required a PIV on nearly every connection from a private fire main to a building. The 2022 edition allows other options, including a wall post indicator valve or a butterfly valve with an indicating handle through the wall. Wall-mounted versions are less preferred because a collapsing wall could take them out.⁷⁸

The sources do not set a standard color for PIVs. A closed valve on an occupied building is a real problem. If one reads SHUT, tell the building manager or the fire department, and leave the valve itself alone.

Why is there a red bell on the outside of a building?

What you see: A round red bell, or a domed gong behind a grille, on an outside wall, often above the FDC. Sometimes a short pipe below it drips after it rings.

It is a sprinkler waterflow alarm. It rings when water is flowing through the sprinkler system, which usually means a sprinkler head has opened.

There are two kinds. A water motor gong is driven by the water itself: water from the alarm port of the alarm check valve spins an impeller, which drives a striker against the gong for as long as water flows. The water then drains out a 1-inch pipe through the wall, which is the drip you sometimes see.⁷⁹ It needs no electricity. An electric bell, horn, speaker or siren does the same job by wire.⁷⁹

NFPA 13 requires a local waterflow alarm on every sprinkler system with more than 20 sprinklers.⁷⁹ The 2021 International Building Code, section [F]903.4.2, requires "an approved audible device, located on the exterior of the building in an approved location" for each automatic sprinkler system.⁷³

The practical point: this bell is local. It is not connected to the fire department, so whoever hears it ringing should call 911 (in the US) or the local emergency number.⁷⁹

What does a red curb or a NO PARKING FIRE LANE sign mean?

What you see: A red-painted curb, sometimes stenciled "NO PARKING FIRE LANE" in white, and red-on-white signs along a driveway or in front of a store.

A fire lane is a lane that must stay clear so fire engines can reach a building. On private property in the US, such as a shopping center or an apartment complex, the fire code requires it to be marked. In the International Fire Code, appendix section D103.6, the signs read "NO PARKING FIRE LANE," at least 12 by 18 inches (30 by 45 cm), red letters on a white reflective background.⁸⁰

Curb paint details are local. Great Falls, Montana, for example, specifies a 6-inch red curb stripe, 4-inch white "No Parking Fire Lane" stencils every 25 feet, and signs every 100 feet, and it limits striping to private roads.⁸⁰

On public streets, curb colors come from state traffic law and mean different things in different states, so a red curb in one state is not the same rule as a red curb in another. Hydrant curbs are covered in the hydrant section; the paint is optional and the no-parking distance applies either way.

In Boston, as of October 2026, parking in a fire lane is a $100 ticket, the same as blocking a hydrant.⁵⁶

Statewide, Massachusetts General Laws chapter 89, section 7A, bars parking in "the fire lanes established by the fire department," lets police or fire personnel tow a car illegally parked in one whether or not there is a fire, and sets a fine of up to $100.⁸¹

What is the red box on a pole with a number on it?

What you see: A red cast iron box with a small door or a white handle, on a short pedestal or a utility pole, with a number plate and often a red lamp or globe above.

It is a fire alarm box, the street end of a fire alarm telegraph. Pulling the handle releases a clockwork mechanism that taps out the box's number over a dedicated circuit to the fire alarm office, which sends engines to that spot. A box reports only where it is, its number, not what kind of emergency it is. Some boxes include a key so firefighters can signal for more help.⁶⁸ Because it has its own wires and runs on clockwork, it can keep working when phone lines and 911 do not.

Boston built the world's first municipal system. William F. Channing and Moses G. Farmer designed it, and it opened in 1852 with 40 boxes and 19 bells, run from a central office at 21 Court Square. They received patent 17,355 in 1857.⁶⁸ The sources disagree on the start date: Wikipedia gives April 29, 1852, at 8:25 p.m., and the Boston Globe gives April 28.⁶⁸⁶⁹

John N. Gamewell bought the rights in 1859, and the Gamewell Fire Alarm Telegraph Co. formed in 1879. Gamewell systems were in 500 cities by 1890, and by 1910 the company held 95% of the market.⁶⁸

Many US cities have removed their boxes. As of April 2026, New York City still had about 15,000 in operation, according to the New York City Fire Museum as quoted by the Globe. Nearby, Salem, Massachusetts was decommissioning its system and Lynn had removed its boxes a few years earlier.⁶⁹ San Francisco relies on its boxes for redundancy.⁶⁸

Do Boston fire alarm boxes still work?

What you see: Red boxes on pedestals or poles across the city, a box on the outside wall of every firehouse, and brass plates reading "Pull The Hook Down Once Only."

Yes. As of April 2026, about 1,250 street boxes were in service, plus about 1,200 master boxes, which connect a building's own alarm system to the fire department, at schools, hospitals, libraries and other buildings.⁶⁹ To use one, pull the white handle down, then push the exposed lever down. The number travels over underground cable to the Fire Alarm Office on the Fenway, where it now appears on a computer screen. A team of 13 maintains the network, and car crashes are a common cause of damage.⁶⁹

The Boston Fire Historical Society adds detail. The office is at 59 Fenway. A pulled box transmits its signal four times, driven by clockwork with no outside power. Boxes are spread across circuits of usually 15 to 20 boxes, arranged so that neighboring boxes sit on different circuits. Every Boston firehouse has a box on its outside wall, and some pole-mounted boxes, such as Box 2649 in Roslindale, carry a red and white "EMERGENCY" sign.⁸² Spreading neighbors across circuits means a single damaged line does not take out every box on a street.

The boxes have earned their keep recently. During a 911 outage on December 28, 2018, a fire at Endicott and Cooper Streets in the North End was reported from a box.⁶⁹ During the statewide 911 outage in June 2024, officials urged residents to use them.⁶⁹⁶⁸ For how 911 calls are normally routed, see How a City Works: 911.

Pulling a box sends fire engines. Use one for a real emergency, and only once: the plate says so for a reason. The publisher's Alarm Club (alarmclub.boston) is a street game built around finding Boston's fire alarm boxes.

What is the red light on top of a Boston fire alarm box?

What you see: A red glass globe or a red-lensed lantern on top of the pedestal or pole, lit at night.

It marks the box so people can find it in the dark. The Boston Globe describes Boston street boxes sitting on pedestals "under glowing red lamps" or on telephone poles.⁶⁹ The Boston Fire Historical Society documents the variety: Box 1231 has a red globe on its stanchion; Box 1373 has an antique red-lens gas light, and the society says gas lights are in service in Charlestown, the North End, Downtown, Beacon Hill and the Back Bay. Some boxes have no light at all, and Box 1895 has a white ball on top instead.⁸²

If you see a lime green box, it is a survivor: some Boston boxes were painted lime green in the 1970s and 1980s, and most have since been repainted red.⁸²

No source found says the lamp flashes or changes when the box is pulled, or that every box has one.

What is the gray meter with a bell-shaped thing on the pipe?

What you see: A gray meter on an outside wall or in a basement window well, with a bell- or dome-shaped device on the pipe beside it and a small vent pipe pointing down.

The meter measures gas use. The bell-shaped device is the gas service regulator, which sits between the shutoff valve and the meter and drops the gas from the pressure in the service line to the low pressure appliances use, typically about 0.25 psi.⁷⁰ Regulators can be indoors or out. The vent is a safety outlet: if the regulator fails, it releases gas through the vent, and that is why indoor regulators vent to the outside.⁷⁰

National Grid's safety guidance for responders is blunt: "Keep all regulator vents clear of snow, ice and debris at all times."⁷⁰ In a snowy city that means not piling shoveled snow against the meter, and not letting ice from a roof or downspout build up over the vent.

The shutoff valve on the pipe before the meter is closed with a quarter turn, so its indicator sits crosswise to the pipe. National Grid says that once it is closed, never reopen it yourself, because only the utility restores service, and never operate valves in the street.⁷⁰ For how gas gets from the street to the meter, see How a City Works: gas and steam.

In Massachusetts, National Grid's installation manual for builders, the "Blue Book" (Revision 2, June 2020), says new meter sets go outside the building unless that is impractical or unsafe. Its checklist keeps the regulator vent at least 18 inches (46 cm) from windows, doors and other openings and above grade, 10 feet (3 m) from mechanical air intakes, and 3 feet (0.9 m) from any source of ignition.⁸³ National Grid's New England meter placement sheet asks for a spot protected from falling snow and ice, such as a gable end, at least 3 feet from windows, doors and electric meters.⁸⁴

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06Manhole covers: shapes, letters and what's underneath

The short version: A manhole cover is a removable lid over a shaft that lets workers reach sewers, drains, water, gas, power or phone lines. Most are round, cast iron and heavy - typically 200-300 lb (90-136 kg) - and the raised letters on top tell you what is underneath and who owns it.⁸⁵ Because covers last for decades, many still carry the names of utilities that merged or vanished long ago, which makes them small, readable pieces of city history.⁸⁶ Do not lift, pry at or step on a rocking cover, and keep clear of an open one; report it to the city instead.

Why are manhole covers round?

What you see: A heavy round metal disc, about two and a half feet across, flush with the road or sidewalk, with a raised grip pattern and lettering.

There is no single answer, and Live Science says so plainly.⁸⁵ The reasons usually given:

• The openings themselves are round, because they are cut with rotating tools.⁸⁵
• A round cover cannot fall through its own opening however it is turned. A square one can, if it is tipped and dropped along the diagonal.⁸⁵
• A round cover can be rolled instead of carried.⁸⁵
• A round cover uses less material than a square one of similar width.⁸⁵

A round lid also seats in its frame at any angle, so a worker does not have to line it up. The question became famous as a Microsoft job-interview prompt, meant to draw out creative answers rather than one correct one.⁸⁵

Size is set by the person going down, not the pipe. Modern openings have to be big enough for a worker wearing breathing apparatus, which is why Nashua, New Hampshire, was switching to a 31.5-inch (80 cm) round cover as of 2011.⁸⁷

Look closely at older covers for small working details. In old New York sidewalks, for example, each cover has a half-inch groove that steers water toward the gutter.⁸⁸

Covers are also rated for the traffic they carry. In Europe, the EN 124 standard sorts them into classes by test load, from A15 (15 kN, pedestrian-only areas) through D400 (400 kN, road carriageways) to F900 (900 kN, aircraft pavements).⁸⁹ In the US, cities write the rating into their own specifications: Tomball, Texas, for example, requires castings that withstand AASHTO HS-20 truck loading without permanent deformation and gives 32 inches as the standard cover diameter.⁹⁰ Kirkland, Washington's standard sewer manhole calls for a locking ring and cover with a 24-inch clear opening.⁹¹

Why are some covers square, rectangular or triangular?

What you see: A square or rectangular lid, often smaller than a manhole and sometimes hinged. Very rarely, a triangular cast-iron lid.

A non-round lid usually sits over a shallow box or a long vault that nobody climbs into: a valve, a meter, a cable splice. Rectangles suit cable chambers. In the UK, telephone footway covers are generally concrete with steel or cast-iron reinforcing around the edges, while covers in the roadway are cast iron.⁹²

Triangles are the oddity. Nashua Foundry began casting triangular sewer covers in the 1920s or 1930s at the suggestion of engineer Walter Ellis, who thought they would rattle less than round ones.⁸⁷ They were laid pointing in the direction of sewer flow, which helped crews find problems.⁸⁷

The 25.5-inch (65 cm) triangles weigh at least 150 lb (68 kg), but they are too small for a worker in breathing gear, so as of 2011 the city was replacing 100-200 a year, out of about 7,500 sewer manholes, with 31.5-inch round covers.⁸⁷ The Nashua Telegraph found no other city with triangular sewer covers; the closest it found was water valve covers in a San Francisco development.⁸⁷

A small triangular lid at a gas station is something else entirely: usually an environmental monitoring well, covered in small lids and grates.

What do the letters on a manhole cover mean?

What you see: Raised letters such as "SEWER", "DRAIN", "WATER", "GAS", "ELEC", "TEL", a set of initials, and often a second, smaller name and a year.

Read a cover in three layers:

Covers can record former local authorities and long-gone companies, which is why historians treat them as evidence. Enthusiasts who photograph and study them are sometimes called gridders.⁸⁶

Foundry names are the small print. Neenah Foundry of Neenah, Wisconsin, founded in 1872 as Aylward Plow Works, makes cast-iron manhole covers, gratings and tree grates, and its name is common on US covers.⁹³ Pont-à-Mousson, whose name is on many Paris covers, dates from 1854 and merged with Saint-Gobain in 1970.⁹⁴ In the UK, telephone covers are marked with type number, date and manufacturer, either on a plate in the concrete face or cast on the underside.⁹²

The utility words are mostly self-explanatory, though the exact labels vary from city to city and utility to utility.

In Boston: a cover decoder

What you see: Initials like BWSC, BWW, B.C.G.Co or N.E.T.&T. Co. on covers around downtown, Chinatown and the Back Bay.

Boston's covers are a layered record of mergers (the Boston section collects the city's other street oddities). The table below lists what has been documented by Forgotten New York's Boston visit and by Universal Hub and its readers.

Universal Hub readers also report covers lettered METWW, CELCo, MassDPW, MassHighway and MassDOT electrical covers, and fiber covers from MCI, MFS McCourt and Level 3.⁹⁶ These come from reader comments, and the meanings of METWW and CELCo are not confirmed.

Electric covers follow the same pattern. Forgotten New York reported in 2015 that many Boston electric manholes still read "E.E.I.Co", that covers replaced later say "Boston Edison Company" or "B.E.Co.", and that no NSTAR-owned manhole in Boston carried the NSTAR name.⁹⁷

Boston's 311 system has a "Sidewalk Cover / Manhole" request type, filed under Sidewalk. In one December 2025 report of a loose sidewalk cover on Batterymarch Street, the case went to the Boston Water and Sewer Commission and was closed in February 2026 as "Sealed loose cover."⁹⁸

How heavy is a manhole cover, and why do people steal them?

What you see: Usually nothing, because the giveaway is a missing cover: an open hole ringed with cones, a plywood patch, or a plastic or composite lid where iron used to be.

Cast iron or concrete covers generally weigh 200-300 lb (90-136 kg).⁸⁵ Small ones can weigh less - Nashua's triangles weigh at least 150 lb (68 kg) - and heavy-duty traffic covers weigh more: Iowa's DOT specifies at least 320 lb (145 kg) for a ring and cover in a traffic area.⁸⁷⁹⁹

That weight is worth little as scrap, but theft spikes when metal prices rise. In 2008 Long Beach, California lost 80 covers in a few months after losing one in the years before; Philadelphia estimated up to 10 a day; Chicago lost 200 in a month; and Cherokee County, Georgia lost 30 in two weeks.¹⁰⁰ One stolen Long Beach cover weighed about 215 lb (98 kg), and recyclers paid only about $10-15 a cover.¹⁰⁰ Historic coal-hole covers in Britain are at risk of theft too.⁸⁶

A missing cover is a fall hazard for anyone, and in the road it can damage a car or throw a cyclist. If you see one, keep people away from it and report it to the city or the utility named on nearby covers, through your city's non-emergency line (see the sister guide's 311 section), or call 911 (or your local emergency number) if it is in a travel lane.

Why do manholes smoke or explode in winter?

What you see: Smoke or flames coming out of a manhole, a cover blown into the air, or a cover with holes or slots that is latched in place.

This is a short pointer; the electric section of the sister guide covers the system. Underground electrical cables fail, often when salty snowmelt gets into aging insulation, and the arcing produces heat and combustible gas that can lift or launch a cover.¹⁰¹ The New York Fire Department logged nearly 4,000 manhole explosion dispatches and more than 45,000 manhole emergencies from 2009 to 2018; in January and February that came to about three explosions a day.¹⁰¹

The main fix you can see is the vented cover, a lid with slots or holes that lets smoke and gas escape instead of building pressure. Con Edison had installed about 100,000 of them by 2015, with about 150,000 to go at roughly 10,000 a year.¹⁰² Con Ed has also installed 21,500 miles (34,600 km) of corrosion-resistant cable, gas monitors and latching vented covers.¹⁰¹ It opposed chaining covers down, warning that a restrained cover could shatter "like shrapnel."¹⁰² If a manhole is smoking, move well away and call 911 or your local emergency number.

What is the orange-and-white steam tube in New York?

What you see: A tall orange-and-white striped tube standing on a manhole in a New York street, with steam pouring from the top.

Con Edison runs a district steam system under Manhattan. Service began in March 1882 in the Financial District, and it is the largest steam system in the US, with about 105 miles (169 km) of pipe serving more than 1,500 buildings, about 250 of which use steam for summer cooling.¹⁰³ The steam is delivered at 450-475°F (232-246°C), and the fuel is about 97% natural gas.¹⁰³

When steam or vapor escapes underground, from a leak or from water hitting hot pipe, crews set up a stack to carry it above cars and people. Con Ed says such conditions are controllable and "not a safety issue."¹⁰³ See the gas and steam section of the sister guide for how district steam works.

Boston has its own district steam system, run by Veolia. A 2014 Veolia brochure said it served 250 customers, including 70% of Boston's high-rise buildings, and about 44 million square feet of buildings in Boston and Cambridge.¹⁰⁴

Why are Japan's manhole covers so decorative?

What you see: A cover cast with a local landmark, festival, flower, mascot or cartoon character, sometimes painted in full color.

Japanese towns design their own sewer covers as civic art. The idea is credited to Ministry of Construction official Yasutake Kameda, who proposed letting municipalities design their own covers to build public support for expensive sewer connections. Neocha puts the count at more than 6,000 custom designs.¹⁰⁵ Commercial designs exist too: Sanrio Puroland unveiled 10 Hello Kitty manholes in late 2017.¹⁰⁶

How do I get Japanese manhole cards?

What you see: A trading-card-sized card with a photo of one town's cover on the front and its location and design story on the back.

Manhole cards are issued by GKP (Gesuido Koho Platform, the Sewerage PR Platform), a group set up in fiscal 2012 to promote sewerage.¹⁰⁷ You collect them in person at designated sites. Tokyo's Bureau of Sewerage, for example, hands them out at five locations, including the Tokyo Sewerage Museum "Rainbow", with a different design at each.¹⁰⁸

Sources for the table: GKP (2016 and 2018 rows) and Japan's Ministry of Land, Infrastructure, Transport and Tourism (2023 rows).^109110107 The 19th release included the first card from outside Japan, for Siem Reap, Cambodia.¹¹⁰ Releases have continued since 2023. GKP's 29th release, announced for summer 2026, added 46 designs from 45 municipalities, bringing the total to 1,311 designs from 783 municipalities and 4 organizations; its overview does not give a cumulative print count.¹¹¹ Check GKP for the current list before planning a trip around one.

The Japan Times dates the shift to designer covers to the 1980s, when only about 60% of Japanese households were connected to municipal sewers.¹¹²

Elsewhere in the world

What you see: In Britain, rectangular covers marked "GPO", "PO" or "BT". In Berlin, a cover crowded with city landmarks. In Paris, cast-iron rings and a foundry name with a picture of a bridge.

United Kingdom. Before British Telecom, the General Post Office ran Britain's phones, and its covers are still everywhere. GPO "Joint Box" covers, later renamed "Covers, Footway", go back to Joint Box Cover 3 in 1904.⁹² Cover type 4A was "marked BT in 1982", and driveway covers came in around 1983.⁹² Early roadway covers were a cast-iron lattice filled with wooden blocks, and some covers have vents or locks.⁹² A joint box is a shallow box where cables are spliced, the British equivalent of a US handhole.

Berlin. Berlin's relatively new Kanaldeckel (sewer covers) show a montage of landmarks. An NPR blogger picked out the Olympiastadion, the Gedächtniskirche, the Reichstag, the Fernsehturm, the Brandenburg Gate and the Siegessäule, and the water utility, Berliner Wasserbetriebe, confirmed that the jumbled one is the Bundeskanzleramt.¹¹³

Paris. A street cover is a regard de chaussée or plaque d'égout.⁹⁴ The Pont-à-Mousson logo shows the bridge over the Moselle at Pont-à-Mousson, which was destroyed in World War II; another maker was the Paris foundry of Noël Chapadaux, which held an 1878 patent.⁹⁴ Some small Paris covers open onto a building's water valve, turned with a long-handled tool, and others onto the gas pipe serving a building.⁹⁴

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07Small lids, grates and glass in the sidewalk

The short version: Most of the small metal things set into a sidewalk are access points: a cap over a water shutoff, a bolted lid over a groundwater test well, a grate over a storm drain, a box where city cable gets spliced. Some are relics, like London's coal-hole plates and the purple glass vault lights in front of old commercial buildings in New York.⁸⁶¹¹⁴ The label or shape usually tells you who owns it, and none of them are for the public to open. Before you dig near any of them, contact your local call-before-you-dig service; in the US that means calling 811 (Dig Safe in New England),¹ and the paint marks section explains how it works.

What is the small round "WATER" or "GAS" cap in the sidewalk?

What you see: A small round cast-iron cap, a few inches across, in the sidewalk or grass strip, marked "WATER" or "GAS".

It is the top of a vertical pipe that reaches down to a shutoff valve. A curb box is a cast-iron pipe running from the sidewalk down to the shutoff valve on a building's service connection, about 4-6 ft (1.2-1.8 m) below the surface; only its round lid, marked "water", shows.¹¹⁵ The valve at the bottom is the curb stop, and the water utility uses a long key to turn a household's water on or off there.¹¹⁵

A valve box is the same idea on a bigger scale: a sleeve and lid in the street over a valve on the water main or gas main itself, so crews can isolate a section of pipe. Caps marked "GAS" are the gas-side equivalent. Paris has both kinds: some small covers open onto a building's water valve, turned with a long-handled tool, and others onto the gas pipe serving the building.⁹⁴

If your curb box is buried, tilted or broken, tell the water utility; it is their access point to your shutoff. Who owns which part of the service line, on either side of the curb stop, varies by city, so check your utility's rules.

What is the small capped pipe near the house?

What you see: A small round cap or plug, often brass, plastic or cast iron, near a building's foundation or in the sidewalk, sometimes marked "C.O." or "SEWER".

Caps like this are commonly called cleanouts: access points to a building's sewer pipe, where a plumber can run a snake or camera when the line backs up. Location and ownership vary by city, so leave the work to a plumber or the sewer utility.

San Diego County, for example, says cleanouts "look like the end of a pipe with a cap on it" and are usually within 3-5 ft (0.9-1.5 m) of the building, sometimes at the front property line. There, the property owner is responsible for the lateral from the building to the public sewer main, and the cap must stay on tight except during servicing.¹¹⁶

What is the bolted cover with a triangle at a gas station?

What you see: A small flush cast-iron lid, about 12 inches (30 cm) across, held down with bolts, at a gas station or former industrial site. It may be triangular or carry a triangle symbol.

It is the top of an environmental monitoring well, a narrow pipe used to sample groundwater or soil vapor for contamination, often from underground fuel tanks. One typical 12-inch triangular cover uses the "API 1615 triangle design" so tank-truck drivers will not mistake it for a fill point, has flush bolts to limit access, and carries an H-20 load rating so vehicles can drive over it.¹¹⁷ API 1615 is a US petroleum-industry practice, and the source here is a vendor product page rather than the standard itself.

The triangle here has nothing to do with Nashua's triangular sewer covers, described in the manhole covers section.

What does "Don't Dump - Drains to River" on the curb mean?

What you see: A small round metal or plastic disc on the curb beside a street drain, or a stenciled message, often with a fish.

It is a public-education marker. Storm drains carry untreated runoff straight to streams, rivers and lakes, so anything poured in - motor oil, paint, dog waste - goes there too.¹¹⁸ Volunteer and school groups often install them. The University of Kentucky's program, for example, puts medallions on the curb behind the drain, where snowplows will not scrape them off, using adhesive at 40-90°F (4-32°C); it tells volunteers to confirm the opening is a storm drain and not a steam vent, and its newer medallions carry a QR code for reporting pollution.¹¹⁸

In cities with combined sewers, where rain and sewage share one pipe, some drains lead to a treatment plant instead, or overflow to the river in heavy storms. The sewers section of the sister guide explains the difference.

What is the difference between a catch basin and a storm drain inlet?

What you see: A grated opening in the gutter, or a slot in the face of the curb (a curb inlet), or both.

They look the same from above. A catch basin has a sump, a low chamber below the outlet pipe where sand and heavier debris settle out before the water leaves.¹¹⁹ A plain inlet has no sump and passes water straight into the pipe. Many US cities say "catch basin" for any street drain.

Catch basins need emptying. One stormwater fact sheet says they should be cleaned before the sump is 60% full, often twice a year in spring and fall, with a vacuum truck; disturbed sump material can smell of hydrogen sulfide, the rotten-egg smell.¹¹⁹

Clearing leaves and snow off the grate in front of your house helps; reaching into the basin does not, and should be left to the city.

Why do drain grates have bars going sideways?

What you see: A drain grate with bars running across the direction of travel, or in a zigzag or curved-vane pattern, instead of long slots parallel to the curb.

Long slots that run the same way as traffic can catch a bicycle wheel and throw the rider. Bicycle-safe grates fix that. In 1980 the US Federal Highway Administration's "Bicycle-Safe Grate Inlets Design Manual" picked three designs out of 11 tested at the Bureau of Reclamation lab in Denver, judged on safety, how well they took in water and how they handled debris.¹²⁰

If you ride and see an old parallel-slot grate in a bike lane, report it to the city.

What is the metal grate around a street tree?

What you see: A flat cast-iron or steel grille with a round hole in the middle, ringing a street tree's trunk, flush with the sidewalk.

A tree grate covers the tree pit so pedestrians have a level surface while rain and air still reach the roots. Parisian Fields contrasts Paris's tree grates with trees elsewhere hemmed in by impermeable asphalt or brick.⁹⁴ The same foundries that make manhole covers make tree grates; Neenah Foundry lists them among its products.⁹³

A trunk can outgrow the center hole as the tree grows. If a grate is pressing into the bark, report it to the city's tree or forestry office rather than prying at it.

What are the small round iron plates in London pavements?

What you see: A small round cast-iron plate, about a foot across, in the pavement outside an old terraced house, often patterned, sometimes with glass studs or a maker's name.

It is a coal hole cover. Eighteenth- and nineteenth-century terraces had coal vaults under the pavement, filled through a hole with a cast-iron cover usually 30-36 cm (12-14 in) across, too small for a person.⁸⁶ The raised patterns gave grip in the wet; some covers have vents, glass or prism inserts, or concrete "non-slip" fills; most are round, set in an iron ring, and a few are square.⁸⁶

Makers were often local. Alfred Syer of Pentonville Road (1830s-1960s) dominated Islington, and Hayward Brothers of Southwark supplied widely; an 1868 Hayward advert priced a 12-inch solid cover at 2s 9d, a ventilating plate at 3s and a glass "illuminating" plate at 6s.⁸⁶ Shephard Taylor coined the term opercula for them and drew hundreds in the 1860s, and modern decorative plates by Keith Bowler (1995) sit in Spitalfields.⁸⁶

Most coal holes are sealed now. Older US cities have similar coal chutes. In Boston, in April 2023, a resident filed a 311 complaint about an uncovered Victorian-era coal chute in the sidewalk outside 470 Commonwealth Avenue in Kenmore Square; the Boston Water and Sewer Commission replied that the chute was on private property and outside its control.¹²¹

What are the purple glass circles in the sidewalk?

What you see: A grid of small glass discs or squares, often lavender or purple, set into a cast-iron or concrete panel in front of an old commercial building.

These are vault lights (in Britain, pavement lights): skylights for the vault under the sidewalk. Thaddeus Hyatt patented round glass lenses set in cast-iron sidewalk panels in 1845, with a prism on the underside that throws daylight sideways into the space below.¹²² The idea came from deck lights on ships, and vault lights lit some of New York's first subway stations and the concourse floor of the original Penn Station (1910).¹¹⁴ Hyatt later spent much of his wealth on the abolition of slavery.¹¹⁴

The purple comes from manganese dioxide, added to clear the glass, which photo-oxidizes under sunlight's ultraviolet over decades.¹¹⁴ Electric light and upkeep costs led owners to remove many, often replacing them with steel diamond-plate.¹²² In Sacramento, streets were raised up to 14 ft (4.3 m) after the 1862 floods, leaving lit vaults under the sidewalks.¹¹⁴ In New York's SoHo and Chelsea, where basements extend under the sidewalk, the panels glow at night.⁸⁸

In Britain, Hayward Brothers sold plain blocks, bull's-eyes, semi-prisms and prisms in the 1870s, the prisms being dearest and most effective; later versions set glass in reinforced concrete, and another major firm was founded by Hyatt (1816-1901), who spent his later life in England.⁸⁶

What are the metal doors in the sidewalk in New York?

What you see: A pair of hinged steel plates, usually diamond-plate, flush in the sidewalk in front of a store, which fold open onto steep stairs or a freight lift.

These are cellar doors, delivery access to a basement under or beside the sidewalk. In Manhattan's older industrial districts, which had no back alleys, buildings were set back 5 to 10 ft (1.5 to 3 m), with steel grates that opened onto basement stairs for deliveries.⁸⁸ They are common in alley-less older cities.

Walk around an open cellar door, not past its edge; the stairs underneath are steep.

Liability for open cellar doors turns on the facts. In Harrington v Azogues Corp. (2021), New York's Appellate Division, First Department, held a building owner not liable after a pedestrian fell through cellar doors that a tenant's employee had opened from the basement; the court found the closed doors were not unsafe and rejected a duty to provide warning lights or signals.¹²³

Why is the grate on the sidewalk warm?

What you see: A large steel grate or set of slotted covers in the sidewalk, with warm air rising from it in winter.

It is a vent for something underground: electrical equipment, steam pipes, or a transit space. Equipment underground makes heat and gas that need a way out. In New York, Con Edison's vented, latching covers and grated covers are designed to let smoke and gas escape instead of building up to an explosion.¹⁰¹¹⁰² New York also has steam pipes carrying 450-475°F (232-246°C) steam under Manhattan streets.¹⁰³

Con Edison's outdoor dining guidance for New York calls the rectangular sidewalk grates "ventilation (transformer) grates." It tells businesses not to cover or place anything on them and to keep objects at least 3 ft (0.9 m) clear on all sides, because "proper ventilation is critical to the safe and reliable operation of our facilities."¹²⁴

Grates can also become electrified. Con Edison's mobile detectors scan for stray voltage on service boxes, manhole covers, gratings, fences and traffic lights; the utility reported checking more than 750,000 structures and 36,000 underground transformers, and in 2009 it found and eliminated 6,266 sources, 60% of them from equipment it did not own.¹²⁵

What does "TRAFFIC SIGNAL" or "STREET LIGHT" on a small cover mean?

What you see: A small rectangular or round lid, concrete, polymer or cast iron, near a traffic light, streetlight pole or curb, labeled "TRAFFIC SIGNAL", "STREET LIGHT", "FIRE ALARM", "FIBER OPTIC" or "ELECTRIC".

It is a pull box or handhole: a shallow box where an underground conduit run is broken so crews can pull cable through and splice it. The label names the system that owns it, often a city or state department rather than a utility; a "FIRE ALARM" lid belongs to a fire alarm system (see fire hardware). Specifications are set by each state DOT or city. Iowa's DOT, for example, specifies 24-inch (61 cm) round handholes with flush cast-iron covers that have "TRAFFIC SIGNAL" cast on top, and marks fiber vault covers "Fiber Optics".⁹⁹

In Boston

What you see: Cast-iron "Don't Dump" plaques on the curb beside catch basins, often rusted, and state electrical covers along the roads.

Boston Water and Sewer Commission's marker reads "Don't Dump" and warns that storm water flows to a river or the harbor; markers go next to catch basins that drain directly to Boston Harbor or the Charles, Neponset or Mystic rivers.¹²⁶ The cast-iron plaques come from a program begun around the late 1980s, under which BWSC required contractors to install them on new or rebuilt catch basins; they look older than they are because cast iron rusts.¹²⁷ As of 2019 Boston had about 30,000 catch basins and 424 miles (682 km) of storm drains, with sewage carried separately to the treatment plant on Deer Island.¹²⁷

Universal Hub readers report electrical covers lettered MassDPW, MassHighway and MassDOT, the successive names of the state highway agency.⁹⁶

Elsewhere in the world

• UK: Coal-hole covers and pavement lights are the classic London survivors, and historic coal-hole covers are at risk of theft.⁸⁶ British telecom joint boxes are covered in the manhole covers section.
• Paris: Small covers open onto building water valves and gas lines, and tree grates stand in contrast to paved-in trees elsewhere.⁹⁴
• US West: Sacramento's raised streets left vault lights over hidden vaults.¹¹⁴

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08Road lines: what yellow, white, solid and dashed mean

The short version: In the US, line color tells you direction and line pattern tells you permission. Yellow separates traffic going opposite ways, white separates traffic going the same way, a solid line discourages or forbids crossing, and a dashed line allows it. Most of Europe paints nearly everything white, the UK uses yellow at the curb for parking rules, and in Japan a solid yellow center line is generally read as "do not cross to overtake." The bumps, grooves and reflectors along the lines are part of the same system.

What do the colors of road lines mean?

What you see: Yellow, white and occasionally red, blue or purple paint and reflectors on the road.

In the US, yellow separates opposing traffic, white separates traffic going the same way, and the other colors have narrow special uses, as the table shows. The US rulebook is the Manual on Uniform Traffic Control Devices (MUTCD), now in its 11th edition (December 2023). Section 3A.03 says markings "shall be yellow, white, red, blue, or purple."³ Green for bike lanes is handled separately, in the bicycle provisions, rather than in that general color list.³¹²⁸

A rule of thumb that falls out of this in the US: if you are driving with a yellow line on your right, you are on the wrong side of the road.

Black outlines are worth knowing about. On pale concrete, a white line can vanish in sunlight, so crews sometimes paint a black stripe beside or behind it. The black carries no meaning of its own.³

What is the difference between solid, dashed, double and dotted lines?

What you see: Unbroken lines, dashed lines, pairs of lines, short tightly spaced dashes, and extra-fat lines.

Under MUTCD Section 3A.04, a solid line discourages or prohibits crossing, and a broken line (dashed) indicates a permissive condition: you may cross it when safe.³ The manual defines the rest of the vocabulary:³

The 10-and-30 dash spacing surprises a lot of people. From a moving car the dashes look about as long as the gaps; standing on the shoulder, a dash is a little shorter than a parked car and the gap is about two car lengths.

Combinations stack the rules. A solid yellow line beside a dashed yellow line means passing is allowed from the dashed side only. Two solid yellows mean no passing from either side.

The UK uses its own patterns. A line of long dashes with short gaps is a hazard warning line (Highway Code Rule 127), and double white lines down the middle govern overtaking (Rules 128-129).¹³⁰

The Department for Transport's Traffic Signs Manual, Chapter 5 (2018 edition, published 2019), builds UK broken lines on two standard modules of one mark plus one gap, 6 m and 9 m long.¹³¹ A hazard warning line uses "the inverse of the mark / gap dimensions for the centre line," which is why it looks like long dashes with short gaps.¹³¹

Why are center lines yellow in the US? A short history

What you see: The ordinary painted stripe down the middle of the road.

Several places claim the first one. Edward N. Hines of the Wayne County Road Commission in Michigan is credited with painted center lines "first used on River Road in Trenton" in 1911; the often-told origin story is that he watched "a leaky milk wagon leave a trail down the street."¹³² Treat the milk wagon as tradition. Hines himself said he had the idea "as early as 1911."¹³³ He also built the world's first mile of concrete road, Woodward Avenue in Detroit, in 1909.¹³²

In California, Dr. June McCarroll of Indio painted a white 4-inch stripe about a mile down the highway near town in "the fall of 1917" and campaigned for the idea. The California Highway Commission adopted center striping in November 1924 and painted 3,500 miles.¹³³ Caltrans credits her with the idea.¹³⁴

A stretch of I-10 was named the "Dr. June McCarroll Memorial Freeway" on April 24, 2002.¹³³ So when people ask "1917 or 1924?", both are right: 1917 is when she painted it, 1924 is when the state adopted it.

Oregon painted a yellow center line on the Columbia River Highway in 1917. The two accounts disagree on who ordered it: one names a Deputy Peter Rexford, the other credits the Multnomah County sheriff, in April 1917.¹³³¹³⁴ Across the Atlantic, Britain is said to have been the first country to paint a white line down the middle of a road, in 1918, though that date comes from a magazine essay.¹³⁵

The color took decades to settle in the US:¹³⁶

The 1961 manual gave three reasons for yellow: it contrasts with white lane lines, yellow was already an accepted warning color, and most states were already using it for no-passing zones.¹³⁶ The 1935 manual standardized the center line but required it only on hills, sharp curves and pavements wider than 40 feet.¹³⁴

Why are the words on the road stretched out?

What you see: "STOP," "ONLY," "SCHOOL," speed numbers and arrows painted in the lane, looking oddly tall and skinny when you stand next to them.

US pavement letters and numerals "should be 6 feet or more in height" (about 1.8 m), per MUTCD Section 3B.21.³ They are drawn elongated on purpose: a driver sees them at a low angle from a distance, which squashes them, so the painted shape is stretched to compensate. The manual says route shields, for example, may be elongated "for proper proportioning when viewed as a marking."³ Word, symbol and arrow markings "shall be white," with listed exceptions.³

Arrows tell you what a lane is for, not what you might like to do from it. A straight-and-right arrow in a lane permits both; a right-only arrow with the word ONLY means that lane must turn.

Japan paints the word 止まれ (tomare, "stop") at stop lines, and it carries the force of a stop sign.¹³⁷

How much stretch? The University of Wisconsin-Madison's TOPS Lab says "current practice in the US is to elongate at a ratio of 2.5:1," and that the ratio of height to width differs from country to country.¹³⁸

What are the white stripes on a speed hump?

What you see: White chevrons or bars painted on a hump in the road, sometimes with a run of white lines before it that get longer and closer together.

Speed hump markings are, in the MUTCD's words, "a series of white markings placed on a speed hump to identify its location" (Section 3B.29).³ They exist so the hump is visible before your suspension finds it.

The optional advance speed hump markings (Section 3B.30) are eight white transverse lines, each 12 inches (30 cm) wide, that grow longer and closer together as you approach.³ The shrinking gaps create the impression of speeding up, which is the point.

What are the bumps and reflectors on the lane lines?

What you see: Small domes or square reflectors glued to the road along the lines; at night they glow in your headlights, sometimes red from the wrong direction.

Raised pavement markers make lanes visible at night and in rain, when a painted line can disappear under a film of water. Under MUTCD Section 3B.14 they "shall conform to the color of the marking" they supplement, so yellow markers go with yellow lines and white with white. The side facing wrong-way traffic "may be red."³ If you ever see a field of red reflectors ahead of you, you are going the wrong way up a ramp or one-way road, or you are looking at a truck escape ramp.³

What are Botts' dots and why is California removing them?

What you see: Rows of small, round, flat white or yellow ceramic domes along lane lines that make the car thump when you drift over them.

These are Botts' dots, raised lane markers you can feel through the tires. They are named for Elbert Dysart Botts (1893-1962), a chemist at the Caltrans Translab. His team found the tactile benefit in field research in spring 1955; the modern pattern of round dots with square reflectors was first tested on I-80 near Vacaville in 1965, and ceramic round markers were adopted in 1966.¹³⁹ That year the California Legislature required them in all areas without snowfall, and California roads eventually carried more than 25,000,000 of them.¹⁴⁰

Critics said the dots "aren't very reflective, don't last very long and may pose problems for autonomous vehicles."¹⁴⁰ On May 24, 2017, Caltrans said it would phase them out gradually as roads are repaved, citing maintenance cost and a six-year study that found no meaningful crash reduction. "Where you see Botts' Dots now, you will now in the future see thermoplastic striping," a Caltrans spokesman said.¹⁴¹

What do blue reflectors in the road mean?

What you see: A single blue reflector in the road, usually beside the center line.

It marks a fire hydrant (see hydrants), so fire crews can find it at night, in snow or behind parked cars. This is a fire-code practice, not an MUTCD meaning: the MUTCD lists blue only for accessible parking.³ Rules are set locally.

One worked example is Riverside County, California: its fire department's Technical Policy TP 06-011 (revised January 7, 2020) says blue reflective markers identify hydrants "for firefighting purposes only." On two-way streets they go 6 inches (15 cm) from the edge of the center line on the hydrant's side of the street; on freeways they go on the shoulder; and blue markers may not be used for anything else.¹⁴² The marker tells a crew which side to look on, roughly where. Leave them in place.

Australia uses the same idea. In Victoria, Fire Rescue Victoria's Guideline No. 29, Street Hydrant Identification (version 2.0, reviewed June 2025), says sealed roads need "a blue raised pavement marker and white reflective triangle marker" for each street hydrant, with in-road markers complying with Australian Standard AS 1906.3.¹⁴³ Roadside hydrant marker posts there are at least 1 m tall, with a red top and a blue reflector facing any likely direction of approach for fire trucks.¹⁴³

What are the grooves that buzz when you drift?

What you see: A row of grooves cut into the shoulder or the middle of the road that roar under your tires, sometimes with the painted line running through them; or raised bars across the lane before a stop.

Rumble strips warn drivers that they are leaving the lane. FHWA groups them by placement: centerline, shoulder or edge line, and transverse (across the lane, before a stop, curve, toll plaza or work zone). A rumble stripe is a rumble strip with the retroreflective line painted into it, which helps at night and in the wet.¹⁴⁴

The crash numbers are large. Citing NCHRP Report 641, FHWA reports:¹⁴⁴

The noise that makes them work is likely also why they are less common next to homes.

Why do road lines glow at night? Paint, thermoplastic and glass beads

What you see: Some lines are thin and flat; others are thick, slightly raised and rubbery-looking. Up close, both are gritty with tiny glass balls.

The glow comes from glass beads dropped onto wet paint or built into tape, which make markings retroreflective.¹⁴⁵ Each bead acts as a tiny lens, bending headlight light in, bouncing it off the paint behind it and sending it back toward the source, which is the driver's eyes. That is why a line can look dull from the sidewalk and bright from behind the wheel.

In the US, the MUTCD makes this a requirement. Markings that must be visible at night shall be retroreflective unless lighting is adequate, and all Interstate markings must be (Section 3A.01).³ Section 3A.05 sets a maintained minimum of 50 mcd/m²/lx (millicandelas per square meter per lux, measured dry) for longitudinal lines on roads with speed limits of 35 mph (56 km/h) or more, with guidance of 100 at 70 mph (113 km/h) or more.³

The material decides how long a line lasts. Iowa State's transportation institute gives these rough lifespans:¹⁴⁵

Tape and thermoplastic are also more visible and less slippery than paint when wet.¹⁴⁶

What are the squares and circles cut into the road at traffic lights?

What you see: Thin black lines cut into the asphalt in squares, rectangles, circles or diamonds near the stop line, with a tar-filled line running off to the curb.

They are not markings. They are sealed slots holding inductive loops: "one or more turns of insulated loop wire wound in a shallow slot sawed in the pavement." The detector electronics run at roughly 10 to 200 kHz; a vehicle over the loop lowers its inductance, and the signal controller registers a car. A 6 by 6 foot (1.8 m) loop is the standard example, and the lead-in wire runs to a pull box at the curb (small lids covers those).¹⁴⁷ Stopping behind the stop line keeps you over the loop. For how the signal uses that information, see How a City Works: traffic lights.

Elsewhere in the world

What you see: White center lines in France or Germany, yellow lines at the curb in London, yellow center lines and white diamonds in Japan.

Europe (Vienna Convention). The 1968 Convention on Road Signs and Signals, concluded at Vienna on 8 November 1968 and in force from 6 June 1978, says painted markings shall be yellow or white, with blue allowed for parking markings. Where a country uses both, "markings of the same class shall be of the same colour," and "white" includes silver or light grey (Article 29).¹⁴⁸ Most of continental Europe chose white for every longitudinal line, so a white center line there means what a yellow one means in the US.

UK. Yellow on a UK road is about parking, not direction. Double yellow lines along the curb mean "no waiting at any time," and single yellow lines mean restrictions at times shown on nearby plates.¹³⁰ Lane and center lines are white, with the hazard warning line and double white lines described above.¹³⁰ The crosswalks section covers UK curb lines in more detail.

Japan. Japan drives on the left and uses white for most lines. According to a rental car company's English guide, a solid yellow center line means do not cross to overtake, a dashed white center line means overtaking is allowed, a solid white line means do not cross, and solid yellow lane lines about 30 to 50 m before an intersection forbid lane changes.¹³⁷ That source is a business, not the police, so treat the detail with some caution.

Prefectural police confirm that a white diamond painted in the lane warns of a pedestrian crossing ahead (or a bicycle crossing).¹⁴⁹¹⁵⁰ Kanagawa police list regulatory markings including no lane change, no parking or stopping and maximum speed, and show stop lines among designation markings.¹⁵¹

Canada. Canada follows the North American color scheme. Ontario's official driver's handbook says "yellow lines separate traffic travelling in opposite directions" and white lines separate traffic going the same way; a solid line at the left of your lane means it is unsafe to pass, and a broken line means you may pass if the way is clear.¹⁵²

For how roads are built and resurfaced, which is when most lines get repainted, see How a City Works: roads.

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09Crosswalks, bike lanes and bus lanes

The short version: In most US states a legal crosswalk exists at every leg of an intersection where sidewalks meet, painted or not, though definitions vary by state; paint mainly makes the crossing visible. Stop lines and rows of white triangles show drivers where to stop or yield. Bike symbols, green paint and boxes at the front of traffic lanes began under federal interim approvals and were folded into the US MUTCD 11th edition (2023), as were red bus lanes. The UK has its own set: zebra crossings with flashing Belisha beacons, zigzags, yellow and red curb lines, and LOOK RIGHT painted at the curb.

What do the different crosswalk patterns mean?

What you see: Two parallel white lines across the street; thick white bars running the same way as traffic; or both together.

The MUTCD says crosswalk markings "shall be white" and sorts them into transverse-line and high-visibility designs.³ In practice there are three common patterns:

A US crosswalk must be at least 6 feet (1.8 m) wide, or 8 feet (2.4 m) at midblock crosswalks where the posted speed is 40 mph (64 km/h) or more (MUTCD Section 3C.03).³

The pattern does not change who has the right of way. It changes how easily a driver sees the crossing. The Pedestrian and Bicycle Information Center gives rough costs of $100 for a two-line crosswalk, $300 for an "international" (bar) crosswalk and $20,000 for patterned concrete.¹⁴⁶

In the US, the word "zebra" is loose shorthand for the bar pattern and carries no special legal meaning. In the UK a zebra is a specific legal device (see below).¹⁵³

Is every intersection a crosswalk, even without paint?

What you see: A corner where two sidewalks meet across a street, with no paint at all.

In most of the US, yes. The Uniform Vehicle Code (2000), Section 1-112, defines a crosswalk at an intersection as the extension of the sidewalk or shoulder across the roadway "regardless of whether it is marked or not." Away from intersections, a midblock crosswalk exists only if it is marked.¹⁵⁴ PBIC puts it this way: an implied crosswalk exists at each leg of signalized and unsignalized intersections unless a sign prohibits crossing, though definitions vary by state.¹⁴⁶

Cities do not paint every crossing, partly because of cost and upkeep and partly because of evidence. Federal guidance came from a study of 1,000 marked and 1,000 unmarked crossings in 30 US cities, published as FHWA-HRT-04-100 in September 2005.¹⁴⁶¹⁵⁴ PBIC recommends that on major roads, especially those carrying more than about 10,000 vehicles a day, markings be paired with other measures rather than used alone.¹⁴⁶ The concern is that paint alone on a wide, fast road can give pedestrians more confidence than driver behavior justifies.

Massachusetts shows how much the wording matters. Its yield law, Massachusetts General Laws chapter 89, section 11, requires drivers to yield to a pedestrian in a crosswalk "marked in accordance with standards established by the department of highways" where no signals are operating, and the section does not address unmarked crosswalks.¹⁵⁵

What is the thick white line before the crosswalk?

What you see: One thick, solid white line across the lane, a few feet before the crosswalk.

A stop line, or stop bar, shows where to stop for a stop sign or red signal. US stop lines should be 12 to 24 inches (30 to 60 cm) wide (MUTCD Section 3B.19).³ Stopping behind it keeps the crosswalk clear and keeps your car over the signal's detector loops, if it has them (see road lines for what the loops look like).

In the UK, a solid stop line goes with a "Stop" sign, at signals or police control, and at level crossings; a double broken line across the lane is a "give way" line.¹³⁰ In Japan, a stop line is paired with the painted word 止まれ (tomare, "stop"), which has the same force as a stop sign.¹³⁷

What are the triangles painted across the road?

What you see: A row of white triangles across the lane, points facing toward you.

A yield line, nicknamed "shark's teeth," marks where to yield: at a yield sign, or before a midblock crosswalk so drivers stop well back and do not hide a pedestrian from the next lane. Under MUTCD Section 3B.19 the triangles are solid white isosceles triangles pointing toward approaching vehicles, with a base of 12 to 24 inches, a height 1.5 times the base, and 3 to 12 inches between them.³

The way to remember the direction: the teeth point at the driver who must yield. The UK uses a double broken give way line for the same job.¹³⁰

What does the bike symbol with arrows on the road mean?

What you see: A bicycle symbol with two chevrons (upside-down V's) above it, painted in an ordinary traffic lane.

That is a shared lane marking, usually called a sharrow. It tells cyclists where to ride in a lane shared with cars, often clear of the door zone of parked cars, and tells drivers to expect bikes. It does not create a bike lane.

Its history: bicycle engineer James Mackay designed a hollow arrow with a cyclist in Denver in the early 1990s; San Francisco later tested it against a French design of chevrons over a bike, and the chevron version became the sharrow. It was added to the MUTCD in 2009.¹⁵⁶ Under the 11th edition (Section 9E.09), sharrows "shall not be used" in bike lanes, bike boxes, two-stage turn boxes, shared-use paths or separated bikeways, and they may not have a green background, though a black one is allowed.¹²⁸

Do sharrows work?

What you see: The same symbol, and arguments about it.

Supporters point to the low cost and the guidance it gives on where to ride. Critics point to the results. A 2016 study by Ferenchak and Marshall of Chicago census block groups found that bike lanes were associated with about 6.5 additional bike commuters per block group, sharrows about 2.1, and no infrastructure about 1.4; injury crashes per 100 commuters fell least in sharrow-only areas.¹⁵⁷

California has since limited them. Senate Bill 1216, approved September 27, 2024, bars new sharrows on highways with a posted speed limit above 30 mph (48 km/h) from January 1, 2025, with an exception at intersections connecting bikeways. The California MUTCD had previously said sharrows "should not be placed on roadways that have a speed limit above 35 mph."¹⁵⁸ Advocates on both sides continue to argue over whether a sharrow is a useful signal or a substitute for a dedicated bike lane; the guide takes no side.

Why are some bike lanes painted green?

What you see: Bright green paint filling a bike lane, or green blocks between dotted lines where a bike lane crosses an intersection or driveway.

Green pavement highlights bike space, mostly at the places where cars and bikes cross paths. For years it was allowed only by request. FHWA Interim Approval IA-14, "Optional use of green colored pavement for bike lanes," was issued April 15, 2011: green could supplement bike lanes and fill between paired dotted lines through intersections, driveways and ramps, but could not replace required lines or symbols, and agencies had to apply and keep an inventory.¹²⁹

A 2017 FHWA status memo still said green could be used only "if the installing jurisdiction has received approval under Interim Approval 14"; that memo was canceled January 18, 2024, superseded by the 11th edition.¹⁵⁹ IA-14 is now terminated and listed among approvals incorporated "in whole or in part" into the 11th edition.¹⁶⁰

Under the 11th edition, green in a crossing extension fills only the area between the dotted lines, and green is not allowed on raised channelizing devices.¹²⁸

In Boston, the city's Better Bike Lanes design page (last updated October 30, 2025) says green markings go "where there is the potential for conflicts between drivers and bicyclists," most often at intersections and driveways, to "alert turning drivers to look for people on bikes." The city also uses green to guide riders into position where they cross Green Line trolley tracks or bridge joints.¹⁶¹

What is the green box at the front of the lane at a traffic light?

What you see: A box across the front of a traffic lane at a light, usually green, with a bike symbol, and the car stop line set back behind it.

An intersection bicycle box, or bike box. At a red light, cyclists wait in front of the cars, where drivers can see them and they get a head start when the light changes. FHWA allowed it under Interim Approval IA-18 on October 12, 2016; that approval has since been terminated and incorporated into the 11th edition.¹⁶⁰

The 11th-edition rules (Section 9E.12): the box is at least 10 feet (3 m) deep between the bike stop line and the car stop line; it has at least one bike symbol; no turn on red is allowed from any lane with a bike box; green, if used, fills the whole box; and boxes spanning several lanes need a pedestrian countdown signal (see signal gear).¹²⁸ For drivers, the practical rule is to stop at the rear line and not turn right on red there.

What is the small box with a bike and an arrow at the corner?

What you see: A small green or white-outlined box with a bike symbol and an arrow, tucked to one side of an intersection, often in the parking lane or beside the crosswalk.

A two-stage bicycle turn box. It lets a cyclist make a left turn (in right-hand traffic) without merging across car lanes: ride straight through on the green, stop in the box and turn the bike to face the cross street, then go when that street gets its green. FHWA allowed it under Interim Approval IA-20 on July 13, 2017, since terminated and incorporated into the 11th edition.¹⁶⁰

Under Section 9E.11 the box has at least one bike symbol and one arrow, a white edge line on all sides, and sits between the bike lane and the through lane or between the bike lane and the crosswalk. No turn on red is allowed where drivers would pass through it, and green, if used, fills the whole box.¹²⁸

Why are some bus lanes painted red?

What you see: A lane painted solid brick red, often with "BUS ONLY" in white letters.

Red pavement marks a transit-only lane so drivers notice it. FHWA Interim Approval IA-22, "Optional use of red-colored pavement for transit lanes," was issued December 4, 2019. Like the bike approvals, it is now terminated and listed among those incorporated "in whole or in part" into the 11th edition.¹⁶⁰ The color makes the lane hard to miss, but the rules about who may use it, and when, are set by the signs.

Not every city uses red. Edinburgh, for example, uses green surfacing for its bus "greenways."¹⁶² For how bus routes and priority work, see How a City Works: transit.

In Boston (more in the Boston section), the city ran a four-week pilot of a morning bus lane on Washington Street in Roslindale, between Roslindale Village and Forest Hills Station, in May 2018 and made it permanent in June 2018; the city says cold weather kept it from painting a later southbound lane red.¹⁶³ The Silver Line's Washington Street corridor in Roxbury and the South End, between Dudley Square and Herald Street, has red bus and bike-only lanes that the city planned to repaint in spring 2020, citing more than 24,000 weekday bus riders.¹⁶⁴

UK zebra crossings and Belisha beacons

What you see: Bold black-and-white stripes across the road, with a flashing amber globe on a black-and-white striped pole at each end.

A UK zebra crossing is a legal device: drivers must give way to pedestrians on it. The beacons came first. Belisha beacons, named for Transport Minister Leslie Hore-Belisha, were introduced under section 18 of the Road Traffic Act 1934.¹⁵³ The crossings they marked were then shown only by "large metal studs in the road surface."¹⁶⁵ After complaints that drivers could not see them, the Ministry ordered thick white stripes in October 1951,¹⁶⁶ and the first zebra crossing opened on Slough High Street on 31 October 1951 after trials from 1949; George Charlesworth is credited with the stripes.¹⁵³ Flashing beacons were mass-produced from January 1953.¹⁶⁶

In the UK the beacon flashes 750 ms on and 750 ms off. Belisha beacons are also used in Hong Kong, Cyprus, Malta, New Zealand, Singapore and Ireland.¹⁶⁵ In North America and much of continental Europe, zebra-style stripes appear at any type of crossing and do not by themselves signal this rule.¹⁵³

What do the zigzag lines near a UK crossing mean?

What you see: White zigzag lines along the curb and down the middle of the road for a stretch before and after a crossing.

Zigzags mark the approach to a pedestrian crossing. They are a later addition: the zigzags "at the kerb and in the centre of the road have been added to all zebra crossings" since the 1969 Abbey Road album photo was taken, which is why the Beatles walk across a crossing without them.¹⁵³

Yellow zigzags outside a school with the words "SCHOOL KEEP CLEAR" mean keep the entrance clear of stationary vehicles.¹³⁰

The Highway Code (Rule 191) says drivers "MUST NOT park on a crossing or in the area covered by the zig-zag lines," and "MUST NOT overtake the moving vehicle nearest the crossing" or the vehicle nearest the crossing that has stopped to give way to pedestrians.¹⁶⁷

What do yellow and red lines along the curb mean in the UK?

What you see: One or two yellow lines along the edge of the road by the curb; or, on major London roads, red lines with "Red Route" signs.

Red routes ban stopping to keep main roads moving. They were first introduced in London in 1991, in north and east London; London's network totals 390 miles (about 630 km) by Wikipedia's count as of October 2026, and they also exist in the West Midlands (since 2003), Leeds (2019) and Derbyshire (2026).¹⁶²

Why is LOOK RIGHT painted on London streets?

What you see: "LOOK RIGHT" or "LOOK LEFT" in large white letters at the curb edge of a crossing, sometimes with an arrow.

A reminder for pedestrians, especially visitors from countries that drive on the right and instinctively look the wrong way. Transport for London has said that under national guidance the markings should "only be installed when traffic approaches from an unexpected direction." After a 2014 resurfacing in King's Cross they were not repainted; following a fatal crash involving a double-decker bus, TfL reinstated them (reported 6 April 2018).¹⁶⁸ In one London cut-through too narrow for a car, "Look Right" and "Look Left" are painted almost touching.¹³⁵

Elsewhere in the world

What you see: A white diamond in the lane in Japan; stripes at every kind of crossing in continental Europe.

In Japan, a white diamond painted in the lane warns of a pedestrian crossing ahead, or a bicycle crossing.¹⁴⁹¹⁵⁰ Painted 止まれ at a stop line means a full stop.¹³⁷

In continental Europe and North America, bar-pattern crossings appear at signalized and unsignalized crossings alike, unlike the UK's legally distinct zebra.¹⁵³ Edinburgh's green bus greenways show that bus-lane color varies even within the UK.¹⁶²

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10What's on a utility pole, top to bottom

The short version: A shared wooden utility pole is stacked by rule. Electric power rides at the top, communication cables (phone, cable TV, fiber) hang lower, and in the US an empty band of roughly 40 inches (about 1 m) separates the two so telecom workers never have to work next to live power.¹⁶⁹ Everything else - the gray transformer, the fuse that bangs in a storm, the coils of spare fiber, the streetlight and the newer 5G boxes - fits into that order. The burned-in stamp near the bottom tells you who made the pole, what it is made of and how strong it is.¹⁷⁰

The pole from top to bottom

What you see: A tall wooden pole with wires and hardware in distinct layers.

This is a shared, or jointly used, utility pole, and its hardware is stacked in a set order. Read it from the sky down: the table below is the order you will find on a typical jointly used US pole. Not every pole has every layer, and a pole with only power or only telecom on it skips the rest.

Some poles also carry an angled steel guy wire to a ground anchor, and some newer poles exist only to carry a small cell.

Why is the power at the top and the phone lines lower?

What you see: Bare wires up high, a gap, then a cluster of black cables lower down.

On a jointly used pole, power sits above a safety zone and communication equipment sits below it, and a vertical clearance has to be kept between the highest communication attachment and the lowest power conductor.¹⁶⁹ The point is that a cable technician climbing to fix a line should never be within reach of the utility's conductors.

The top wires are the utility's primary lines, the medium-voltage feeders that run through a neighborhood. They sit on insulators so they never touch the wood, and crossarms spread them apart. Telecom companies attach below as tenants. Rearranging existing cables to make room for a new one is called make ready.¹⁷³

Primary distribution voltages range from about 2.3 kV to about 35 kV depending on local practice, and the most common US voltage is 12.47 kV, which is 7.2 kV between each wire and ground.¹⁷⁴ Two Rivers Water & Light, a municipal utility in Wisconsin, describes its primary wires as usually carrying 12,000 volts from a substation, and the single wire lower down as the neutral, which sits below the transformer and "acts as a line back to the substation."¹⁷⁵ Where a line has only one phase wire, a neutral is always provided as the return path.¹⁷⁴

A pole is deeper than most people guess. The industry rule of thumb for burial is "10% plus 2 feet," so a 70 ft (21 m) pole has about 9 ft (2.7 m) underground.¹⁷⁰

What is the gray can on a power pole?

What you see: A gray metal cylinder bolted high on the pole, with one or two small porcelain bushings on top and wires running down toward houses.

This is a distribution transformer. It takes the medium-voltage primary line and steps it down to the voltage that the service wires carry into buildings. Wires from its low side run along the street to the next pole or straight to a house.

You will almost always find a fuse cutout mounted close by, because cutouts sit high on poles near transformers or along primary lines to protect equipment from surges and overloads.¹⁷¹ When people say a transformer "exploded" in a storm, the noise often came from that fuse instead (see the next item).

Distribution transformers are typically rated below 200 kVA, and aerial units larger than about 75 kVA may sit on a platform carried by one or more poles.¹⁷⁴ In North America the transformer's low-voltage winding is center-tapped with a grounded neutral: lights and outlets run at 120 V between one hot wire and the neutral, and heavy loads such as dryers use both hot wires for 240 V.¹⁷⁴ How many homes one can serves depends on density. In urban areas several homes may share one transformer, while rural lines may need one transformer per customer.¹⁷⁴

The sister guide explains how power gets from the substation to this can in How a City Works: Power.

What was that loud bang from the power pole during the storm?

What you see: A diagonal porcelain or polymer holder with a tube in it, near the transformer. After a storm, one tube may hang open, pointing down.

That holder is a fuse cutout, a fuse holder for the primary line. When current becomes unsafe, a fuse inside melts, the barrel swings open and power is cut.¹⁷¹ The loud, sharp crack is the fuse operating, and Indiana Connection describes it as a sign that the system is isolating a problem.¹⁷¹ Causes include lightning, storms, vehicle accidents and high demand.¹⁷¹

So the shotgun sound at the start of an outage is often the system doing its job, cutting off one section so the rest of the line stays up. A tube hanging open is the visible sign that this cutout has operated, and a utility crew has to replace the fuse. Do not try to close it, poke it or go near a downed wire. Report the outage to your utility.

What is the empty gap between the power and the phone lines?

What you see: A clear band of pole, roughly a yard tall, between the lowest power hardware and the highest phone or cable line. Sometimes a streetlight arm or a pipe crosses it.

In the US this is the communication worker safety zone, set by the National Electrical Safety Code (NESC) in Rules 235C and 238. It is commonly about 40 inches (102 cm), with less allowed in some cases and more required in others.¹⁶⁹

Only a few things may sit inside it: span wires or brackets carrying streetlights and traffic signals, their drip loops, and vertical risers that carry cable from overhead to underground.¹⁶⁹ A riser is the pipe or molding you see running down the pole into the ground.

Streetlights get special treatment. Their clearance is 4 or 40 inches depending on conditions. The 2017 edition of the NESC raised the clearance for ungrounded streetlights from 20 to 40 inches, which effectively bars them from the zone. A grounded streetlight with a visible bond may sit 4 inches (10 cm) away. Cameras or radios mounted on streetlight brackets must keep the full 40 inches.¹⁷⁶

What are all the black cables lower down?

What you see: Several black cables in the lower part of the pole, each wrapped in a spiral of thin wire that ties it to a steel strand. Sealed cylinders or boxes hang along them, and sometimes a small box with cooling fins.

These are the communication attachments: telephone copper, cable TV coax and fiber, each usually owned by a different company. New fiber is lashed to existing steel strand, and rural crews sometimes have to install a messenger wire first.¹⁷³ The spiral is the lashing wire that holds cable to strand.

The sealed cylinders and boxes are splice closures, which protect the points where cables are joined. A finned box on a coax line is a cable TV amplifier. One survey of a single run in Santa Monica, California counted "six fiber splice closures, one copper closure and one CATV amplifier."¹⁷³ Most fiber splicing is done on the ground, not up the pole.¹⁷³

Older multipair copper phone cables were sometimes pressurized with nitrogen to keep moisture out.¹⁷³

Telling fiber from coax from copper by eye is hard, and this guide found no reliable method to recommend. The closures, amplifiers and slack loops are better clues than the cable itself.

Why is there a coil of cable hanging on the line? (fiber "snowshoes")

What you see: A long oval of black cable stretched between two plastic or metal racks shaped like snowshoes, hanging in the middle of a span.

This is stored spare fiber, a slack loop. The racks are usually called snowshoe fittings.¹⁷³ Crews leave the extra length on purpose: each end needs enough slack to come down the pole, go into a vault and reach a splicing truck parked at the curb.¹⁷³ That lets a technician repair a break or add a connection later without splicing in a new piece of cable.

The same EC&M survey counted "seven hanging storage loops of excess fiber" along one stretch of street.¹⁷³ Spotting a snowshoe is a good clue that a line carries fiber.

How do you read the numbers and tags on a utility pole?

What you see: A burned-in stamp or small metal plate on the wood, with letters and numbers. You may also see oval aluminum tags with years, colored tags, or orange tape.

The main stamp is the pole brand, its birthmark. Brands show class and height, owner, manufacturer, wood species, preservative treatment, batch number and date. Ameren's example reads Southern Pine, Penta (pentachlorophenol) treatment, Class 1, 50 ft.¹⁷⁰ Pole class is a strength rating. The treatment retention shown on the brand is the minimum for that treatment charge.¹⁷⁷

Under rural utility (RUS) rules, the bottom of the brand is placed 10 ft 2 in (3.1 m) from the butt on poles 50 ft and shorter, and 14 ft 2 in (4.3 m) on poles 55 ft and taller. The brand faces the pole's "face," the concave side of greatest curvature.¹⁷⁷ Combine that with the burial rule of thumb and a 40 ft pole set 6 ft deep has the bottom of its brand about 4 ft above the sidewalk.

Other tags tell the pole's life story. In Ameren's system:¹⁷⁰

Tag colors and formats vary by utility, so read the table as one example, not a national code.

Inspectors decide whether a pole stays up by combining a visual check, sounding with a hammer up to about 76 inches (1.9 m), and boring. A safe pole needs about 2 inches (5 cm) of sound outer shell.¹⁷⁰

What is the angled wire with the yellow tube?

What you see: A steel cable running from high on the pole down to an anchor in the ground, often sheathed near the bottom in a long yellow plastic tube.

This is a guy wire. It holds the pole against the sideways pull of its wires, which is why you see guys at corners and at the ends of lines. Utilities treat a broken or loose guy wire as a condition that affects pole integrity or creates a hazard.¹⁷⁰ If you see one slack or snapped, report it to the utility rather than touching it.

The plastic sleeve is a guy guard or guy marker, and its job is to make the wire easy to see. In California, the state utility code (CPUC General Order 95, Rule 86.9) requires a marker of metal, plastic or other suitable material, at least 8 ft (2.4 m) long, on any anchor guy exposed to traffic.¹⁷⁸ In Ontario, Canada, the Electrical Safety Authority says guys must be marked "in a substantial and conspicuous manner" where people or vehicles may pass, treats bright yellow as the reference color, and does not accept colors designed to blend in with the surroundings.¹⁷⁹

What is the thing on top of a streetlight?

What you see: A curved arm holding a flat-bottomed fixture over the street, often called a cobrahead, with a small round puck twisted into the top of the head.

The puck is a photocontrol, which switches the light on at dusk. It plugs into a standard twist-lock socket defined by ANSI C136.41. Newer versions of that socket have extra pins: the 5-position receptacle has 3 power and 2 dimming or signal contacts, and the 7-position version has 3 power and 4 dimming or signal contacts. They support 0-10 V or DALI dimming.¹⁷²

That is why the puck on some lights looks bigger or has a small antenna. A "smart" node can sit in the same socket as the old photocell and dim, monitor or report on the light.

Where a streetlight bracket passes through the communication worker safety zone, it is allowed in only if grounded with a visible bond.¹⁷⁶ Utility-owned and city-owned light tags both appear on poles, so the light and the pole may belong to different owners.¹⁷⁰ The sister guide covers lighting in How a City Works: Streetlights.

What is the box on top of the light pole? Is it 5G?

What you see: A cylinder or shroud on top of a pole, sometimes a new, taller metal pole, with gray boxes strapped lower down and sometimes an electric meter.

It is probably a small cell, a low-power cellular antenna that fills in coverage between the big towers. One city describes the antennas as "generally cylindrical and shrouded at the top of the pole," with equipment in a pole-mounted or internal cabinet and an electric meter. The poles run about 30-40 ft (9-12 m), while macro towers are about 2 miles (3.2 km) apart.¹⁸⁰

In the US, cities have limited say over whether these go up. The City of Thornton, Colorado explains that in a September 2018 ruling, the FCC said US cities cannot prohibit small cells in the public right-of-way, though they may set design guidelines.¹⁸⁰ This helps explain why many cities publish small cell design guides that specify shroud shapes, colors and cabinet placement.

An electric meter on the pole is a strong hint, since a plain streetlight usually does not have one.

In Boston

Boston's poles carry the same layers described here, and as a US city it falls under the NESC clearance rules above. For more on the city's street hardware, see the Boston section.

Across Massachusetts, "a substantial majority" of utility poles are jointly owned by the investor-owned electric companies (NSTAR Electric, National Grid and Unitil) and Verizon, according to a January 17, 2025 notice from the state Department of Public Utilities and Department of Telecommunications and Cable.¹⁸¹ An undated Dorchester Reporter article describes Boston's wooden street poles as jointly owned by NStar and Verizon, with maintenance split by neighborhood - NStar for areas including Brighton, East Boston and Jamaica Plain, Verizon for areas including Dorchester, Roxbury and South Boston - and notes that complaints sent to the wrong company get forwarded.¹⁸² This guide did not find a cited source on how Boston pole numbers are formatted.

Elsewhere in the world

The communication worker safety zone and its 40-inch figure come from the NESC, which is a US code. Other countries set their own clearance rules, and this guide has not researched them.¹⁶⁹ Brand formats, tag colors and the order of attachments also vary by utility and country, so treat the US tables above as a starting point outside the US.

The small cell rule above is a US federal ruling, so outside the US the permits for these boxes follow local law.

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11The gear on traffic signal poles

The short version: A signal pole carries much more than red, yellow and green: the yellow-edged backplates, the blinking left-turn arrow, the ticking push button, the small blue light and the assortment of cameras each have a specific job. Backplates make signals easier to see, and many cameras on signal arms detect waiting vehicles rather than record drivers.¹⁸³¹⁸⁴ Mid-block, some US crossings use beacons that stay dark until someone pushes a button. Elsewhere, UK crossings have animal names, Berlin's walking man wears a hat, and in Japan the green light is called blue.

Why do some traffic lights have a yellow border?

What you see: Signal lights set in a black rectangular frame with a thin, bright yellow outline that glows in headlights.

The black frame is a backplate. It gives the lit lenses contrast against a bright sky. The yellow strip, 1 to 3 inches (2.5-7.5 cm) wide, is retroreflective, so it shines back at drivers at night and outlines a dark signal during a power outage.¹⁸³ The Federal Highway Administration (FHWA) lists backplates with retroreflective borders as a Proven Safety Countermeasure and credits them with a 15% reduction in total crashes (CMF ID 1410).¹⁸³

FHWA says the borders help older drivers and drivers with color-vision deficiency, and that agencies can retrofit existing backplates cheaply with reflective tape. The trade-off is that a backplate adds wind load to the mast arm.¹⁸³

What does a flashing yellow arrow mean?

What you see: A left-turn signal with four lights stacked vertically, where the yellow arrow blinks.

A flashing yellow arrow means a permissive left turn: you may turn after yielding to oncoming traffic and pedestrians.¹⁸⁵¹⁸⁶ In Wikipedia's wording, it allows traffic to "cautiously enter the intersection" while yielding.¹⁸⁶ A solid green arrow, when the same head shows one, means the turn is protected and oncoming traffic is stopped.

The flashing yellow arrow was formally authorized in the US federal Manual on Uniform Traffic Control Devices (MUTCD) in 2009, and Minnesota followed in 2011. Drivers read it well: in a University of Minnesota survey, about 94% of respondents understood it without a sign and 96% with one.¹⁸⁵

What do the countdown numbers and push buttons do?

What you see: A box showing a white walking person, an orange hand and a number counting down. A button sits on the pole nearby.

The countdown shows the seconds left before the signal changes. In the US and Canada, countdown timers usually accompany the flashing hand, and in the UK they run during the "blackout" period when no pedestrian figure is lit.¹⁸⁶ Studies show improved pedestrian compliance with mixed results, and no significant change in drivers running red lights.¹⁸⁶

The push button tells the controller that someone is waiting. Cambridge, Massachusetts tells pedestrians that at its signals with buttons, the WALK phase is skipped if nobody presses, while at intersections with no buttons the WALK comes on every cycle.¹⁸⁷

Not every button is wired that way. The Boston Globe reported in July 2017 that the vast majority of buttons in downtown Boston did nothing, because the signals there run on a fixed schedule with a regular WALK; some worked only overnight, and buttons in outlying neighborhoods often still worked by day.¹⁸⁸ The Globe described no visible way to tell a working button from a dead one, and the city did not provide a list of affected intersections.¹⁸⁸

Why does the crosswalk button tick or vibrate?

What you see: A larger push button with a raised arrow and a small speaker, ticking steadily about once a second. When the walk signal comes on, it rattles rapidly or speaks, and the arrow vibrates.

This is an accessible pedestrian signal (APS), built for blind and low-vision pedestrians. The steady tick is the locator tone. It repeats once per second and lasts at most 0.15 seconds, so it is not mistaken for a backup alarm.¹⁸⁹ It helps people find the button and line up with the crossing.

The raised arrow points parallel to the crosswalk. During WALK it vibrates, which works at noisy intersections and for deafblind pedestrians. The audible WALK may be a rapid repetition of the locator tone, a different tone, or speech.¹⁸⁹

The rapid "machine-gun" tick is the sound guidelines recommend. Older cuckoo-and-chirp signals confused people and could be mimicked by mockingbirds. Pressing and holding the button often plays the street name, and speech messages are preferred when two buttons are less than 10 ft (3 m) apart, so it is clear which crossing is getting the WALK.¹⁹⁰

In Boston, the city's APS specification calls for a 0.15-second locator tone at about one per second with automatic volume adjustment; a latching LED, tone and vibration when the button is pressed; optional speech WALK messages; a 5 x 7 inch (13 x 18 cm) MUTCD R10-3 sign with Braille and a matching arrow; messages programmable over Bluetooth; and operation from -25 to 165 F (about -32 to 74 C).¹⁹¹¹⁹²

What is the blue light on top of a traffic light?

What you see: A small blue light, sometimes white, on top of, under or behind a signal head, or on the mast arm. It is lit whenever the signal is red.

It is a red-light confirmation light, an enforcement aid and not a camera. The light turns on with the red, so a police officer parked downstream or across the intersection can see that a driver entered on red without being able to see the signal face. Bismarck, North Dakota, which uses them, says they let officers see violations from a safe position and that "red-light confirmation lights do not use automated photography."¹⁹³

Mounting varies: Bismarck describes lights on the top, bottom or rear of a signal head.¹⁹³ Hudson, New Hampshire installed one on March 16, 2020, the first in that state, and it shows blue when the signal is red and white when inactive.¹⁹⁴

They appear in scattered US cities. As of October 2026 this guide found no record of them in Massachusetts, the UK or the EU.

What is the small sensor pointed down the road? (emergency preemption)

What you see: A small cylindrical or bullet-shaped sensor, often with a dark lens, on the mast arm and aimed at approaching traffic.

This is likely an emergency preemption detector, a receiver that lets fire trucks and some other vehicles request a green light. Optical sensors respond to strobes flashing at a very high rate, and some respond only to specific patterns. Opticom, one widely used system, "combines GPS and Infrared technology."¹⁹⁵

The vehicle's emitter sends the coded signal, the detector passes it to the signal cabinet, and the controller ends the conflicting phase early. The sister guide covers how emergency calls turn into a dispatched truck in How a City Works: 911.

Some cities add a confirmation light for the emergency driver. Bismarck, North Dakota uses white lights: dark most of the time, steady white when the system has received the vehicle's infrared request, and flashing white when it is already serving a call from another approach.¹⁹⁶ The blue light described above, by contrast, comes on with every red, whether or not an emergency vehicle is near.¹⁹³ Colors are not uniform everywhere: Hudson, New Hampshire's enforcement light shows white when inactive.¹⁹⁴

What are the cameras on traffic lights for?

What you see: Assorted small cameras, domes and boxes on or above the signal arms, and sometimes a larger box on its own pole near the stop line.

Many devices on signal arms are vehicle detection: they tell the controller that a car is waiting. Bloomington, Minnesota describes its video detection cameras as mounted high on the signal structure with a fixed focus and no pan or zoom. A processor watches predefined zones and places a call to the controller. The city says there is "no constant surveillance or archiving," though some diagnostic clips may be kept briefly.¹⁸⁴

The older method is the inductive loop, a wire loop saw-cut a few inches into the pavement; a vehicle above it changes the inductance, and the signal cabinet on the corner receives the call.¹⁸⁴

LegalClarity, a legal-information site, offers rough visual cues for the other kinds:¹⁹⁷

These are general cues from a secondary source, not a manufacturer standard, and look-alikes exist. Camera enforcement and ALPR are debated; this guide stays neutral and describes only how to tell the devices apart.

In Massachusetts, camera ticketing has needed new state law. Senate bill S.2344 of 2025, "An Act relative to traffic regulation using road safety cameras," was reported favorably by the Joint Committee on Transportation on July 7, 2025 and sent to Senate Ways and Means.¹⁹⁸ Senate bill S.3225 would create an automated road safety enforcement program for speed only, in school, work and designated safety zones, with a warning first, fines of $25 or $100, at most one camera per 5,000 residents, and a ban on facial recognition.¹⁹⁹

Axios Boston reported on August 3, 2026 that the Senate had passed speed-camera authority as an amendment to an economic development bill, which would make Massachusetts allow them for the first time, while the House had not acted. Gov. Maura Healey has long pushed for the measure, and critics argue cameras raise privacy and racial-equity concerns or serve as a revenue tool.²⁰⁰ As of October 2026, this guide had not confirmed a later outcome.

The sister guide explains controllers, phases and detection in How a City Works: Traffic lights.

What is a HAWK signal?

What you see: Over a mid-block crosswalk, a signal head with two red lights side by side above one yellow. It is dark most of the time.

This is a pedestrian hybrid beacon (PHB), often called a HAWK. It rests dark until a pedestrian pushes the button. Then it runs: brief flashing yellow, steady yellow, steady red with WALK for pedestrians, flashing hand, alternating flashing red, and back to dark. It is used only with a marked crosswalk and appears in Chapter 4F of the US MUTCD. FHWA cites reductions of up to 69% in pedestrian crashes and 29% in total crashes.²⁰¹

The HAWK was developed in Tucson, Arizona, which had more than 60 of them at the time of FHWA's evaluation. A before-and-after study of 21 sites found 29% fewer total crashes, 69% fewer pedestrian crashes and 15% fewer severe crashes, though the severe-crash change was not statistically significant.²⁰²

During the alternating flashing red, FHWA says drivers may proceed across the crosswalk "after coming to a complete stop" and "if it is safe to do so." Because drivers were seen waiting through the whole flashing red even with the crosswalk clear, FHWA allows an optional R10-23a word sign, CROSSWALK, STOP ON RED, PROCEED ON FLASHING RED WHEN CLEAR, in place of the standard symbolic CROSSWALK, STOP ON RED (R10-23) sign required by Section 4F.02 of the 2009 MUTCD.²⁰³

What are the flashing yellow lights at a crosswalk?

What you see: Two small rectangular yellow LED bars under a pedestrian crossing sign that strobe in a fast left-right pattern after someone presses a button.

This is a rectangular rapid flashing beacon (RRFB), used at crosswalks without a traffic signal. It stays dark until activated by a push button or by passive video or radar detection, then flashes in an alternating high-frequency pattern.²⁰⁴

It is an FHWA Proven Safety Countermeasure, credited with up to 47% fewer pedestrian crashes and up to 98% more drivers yielding (CMF ID 9024). It works best on multilane roads with speeds under 40 mph (64 km/h). In the US it appears in Chapter 4L of the MUTCD 11th edition (2023).²⁰⁴

Unlike a HAWK, an RRFB never shows red. It warns drivers that someone is crossing.

What are the rows of blue bikes and the kiosk? (Bluebikes in Boston)

What you see: A row of docks holding blue bicycles, a tall kiosk with a solar panel and a map, or newer freestanding "pillar" docks, often beside a signalized corner.

This is a docked bike-share station. Boston's system launched as Hubway on July 28, 2011 and was renamed Bluebikes on May 9, 2018 under a sponsorship with Blue Cross Blue Shield of Massachusetts. Its bikes and docks come from PBSC, with newer docks from 8D Technologies, and the station kiosk is solar-powered. It had more than 400 stations by 2023.²⁰⁵

Bluebikes is jointly owned by 13 municipalities: Arlington, Boston, Brookline, Cambridge, Chelsea, Everett, Malden, Medford, Newton, Revere, Salem, Somerville and Watertown. The newer Pillar docks are independently powered by solar panels, with an optional grid connection for charging e-bikes. Boston began a 100-station expansion in September 2024.²⁰⁶

Solar power is why most stations can go in without a grid hookup.

A short history of the traffic light

What you see: The three-color signal, everywhere.

The first traffic signals were police-operated semaphores with red and green night lights in London's Parliament Square in 1868. Lester Wire built an electric traffic light in Salt Lake City in 1912, and the American Traffic Signal Co. installed an electric signal in Cleveland, Ohio in August 1914.¹⁸⁶

Elsewhere in the world

Why does the UK show red and amber together?

What you see: Red, then red and amber lit together, then green, then amber alone.

In the UK, red means stop; red and amber together mean prepare to go but do not proceed; green means go if the way is clear; and amber alone means stop unless it is unsafe to do so.¹⁸⁶ US signals skip the red-and-amber step.

What is the difference between zebra, pelican, puffin, toucan and pegasus crossings?

What you see: UK crossings with animal names. Some have striped poles topped with flashing orange globes. Some show a red or green figure across the road, others on the button box.

All rows: Carbuyer.²⁰⁷

At a puffin, then, you look at the button box, not across the road, to see when to go.

What is the Berlin traffic light man called?

What you see: In Berlin and eastern Germany, a stocky pedestrian figure in a hat, striding when green and standing with arms out when red.

This is the Ampelmännchen, "little traffic light man." Traffic psychologist Karl Peglau presented the design on October 13, 1961, meant to be clearer to children. Introduction was delayed to 1963, and the first successful testing came on Unter den Linden in 1969. The hat raised worries that the figure looked "bourgeois."²⁰⁸

After reunification the figures began to be removed. Designer Markus Heckhausen started making lamps from old units in 1995, and the "Save the Ampelmännchen!" committee formed in 1997 to bring the figure back.²⁰⁸

Why does Japan call green lights blue?

What you see: In Japan, the go light looks distinctly blue-green, and people call it ao, blue.

Japanese signals use 青 (ao), usually translated as blue, though the light is green, a holdover from older Japanese usage. In 1973 the go light was decreed to be "the bluest possible shade of green," keeping an internationally recognizable green while matching the word.¹⁸⁶

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12Sign shapes and colors, decoded

The short version: In the US, a road sign's outline and background color are a code, set by the federal Manual on Uniform Traffic Control Devices (MUTCD). An octagon always means stop, a point-down triangle always means yield, yellow means a general warning, orange means a work zone and fluorescent pink means a crash or emergency scene. Street name signs and parking signs follow their own rules about letter size, color and stacking. Most of Europe uses a different grammar under the 1968 Vienna Convention, so a sign you know at home can look unfamiliar abroad.

What do the different sign shapes mean?

What you see: Signs cut into distinct outlines - octagons, triangles, a sideways pennant, a house-shaped pentagon, a circle, yellow diamonds and plenty of plain rectangles.

The MUTCD says certain shapes "shall be used exclusively for specific signs or series of signs."²⁰⁹ The point is that you can read the sign from its silhouette alone - from behind, at dusk, or with snow stuck to the face. The 2023 11th edition of the federal manual could not be checked directly for this table; the list below comes from Delaware's state MUTCD, which adopts the federal shape rules.²⁰⁹

Source for the table: Delaware MUTCD Section 2A.09.²⁰⁹

Under the 11th edition, warning signs are generally "diamond-shaped (square with one diagonal vertical)" with a black legend and border on yellow.²¹⁰ The rectangle is the catch-all, which is why speed limits, street names and freeway guide signs all share it.

What does a sideways triangle sign on the left mean?

What you see: A long yellow triangle pointing to the right, mounted on the left side of a two-lane road, reading NO PASSING ZONE.

This is the pennant, a shape used for exactly one sign: No Passing Zone, code W14-3, in Section 2C.53 of the 11th edition.²¹⁰ On conventional roads it measures 48 x 48 x 36 inches (about 122 x 122 x 91 cm).²¹⁰ It sits on the left because that is the side a passing driver is looking at as they pull out.

What does a pentagon-shaped sign mean?

What you see: A house-shaped yellow-green sign with figures of children walking, or a smaller pentagon with a number on it in rural areas.

A point-up pentagon with squared-off bottom corners is reserved for school advance warning; the same outline with tapered bottom corners is a county route marker.²⁰⁹ Under the 11th edition, school and school bus warning signs "shall have a black legend and border on a fluorescent yellow-green background."²¹⁰

What does a round yellow sign before railroad tracks mean?

What you see: A circular sign on the approach to a level crossing, well before the tracks.

The circle is reserved for grade crossing advance warning.²⁰⁹ It tells you tracks are ahead; the crossbuck - the X-shaped sign - marks the crossing itself.²⁰⁹ The 11th edition also lists related grade crossing advance warning signs with the codes W10-2, W10-3, W10-4, W10-11 and W10-12.²¹⁰

What do the different sign colors mean?

What you see: Yellow, neon yellow-green, orange, green, blue, brown, red, black and the occasional hot pink sign.

The color table comes from trafficsign.us, a long-running reference that tracks the MUTCD, rather than from the manual's own table, which could not be loaded.²¹¹

Why are some school and crosswalk signs neon green?

What you see: A glowing yellow-green sign with a walking figure, a bicycle or two children, much brighter than the yellow signs around it.

That color is fluorescent yellow-green. The 11th edition makes it mandatory for school and school bus warning signs; for pedestrian, bicycle and playground warnings, agencies "may" use either yellow or fluorescent yellow-green.²¹⁰ So one town's crosswalk sign can be plain yellow and the next town's neon, and both are correct.

What does a pink road sign mean?

What you see: A hot pink or magenta sign, often on a portable stand, reading something like ACCIDENT AHEAD or DETOUR.

Fluorescent pink is the background for incident management signs - temporary signs put out at crashes and other emergencies.²¹¹ Think of it as the short-notice cousin of orange: orange is for planned work zones, pink is for the unplanned.²¹¹

What do sign codes like W14-3 mean?

What you see: Nothing on the sign face. The codes show up on work orders, sign shop labels and in the manual itself.

Every standard US sign has an alphanumeric designation, explained further in Fonts, stickers and numbers on signs. The 11th edition's warning chapter is full of them: W1-8 Chevron Alignment, W7-1 Hill, W2-1 Cross Road, W3-5 Reduced Speed Limit Ahead, W14-3 No Passing Zone.²¹⁰ A trailing "P" marks a plaque, a small supplementary sign mounted under another one, such as the W13-1P Advisory Speed plaque.²¹⁰ Mile markers are the D10-1 series.²¹² FHWA publishes the full drawings for each code in its book "Standard Highway Signs," with a 2024 edition linked from the MUTCD site.²¹³

The two most familiar codes are R1-1 for the Stop sign and R1-2 for the Yield sign, both listed in the 11th edition's table of reserved shapes in Section 2A.05.²¹⁴ The street name sign is D3-1, detailed in Section 2D.45.²¹⁴

The leading letters name the sign family. Minnesota DOT's Standard Signs and Markings manual, which it is revising in 2026 to follow the state's 11th-edition MUTCD, files signs under R (regulatory), W (warning), D (guide), I (informational), E (exit), M (route signs, detour signs and auxiliary plaques), S (school), OM (object markers), G (construction) and PM (pavement messages), plus an X section for miscellaneous signs.²¹⁵ That is Minnesota's arrangement; other states publish their own sign books.

Other countries keep their own catalogs. Australia's kangaroo sign is W5-29, for example.²¹⁶

Why are stop signs octagons, and were they ever yellow?

What you see: A red octagon with a white border and the word STOP, in the US normally about 30 inches (76 cm) across.

The stop sign was born in Detroit. Signalfan.com puts the "first recorded stop sign" there in 1915, black letters on white metal;²¹⁷ Wikipedia credits police sergeant Harry Jackson with a 1914 sign and says Michigan adopted stop signs statewide in 1915.²¹⁸ The sources disagree on the year by one.

In 1922 a national committee backed by AASHO (today's AASHTO) chose the octagon, partly so a driver facing the back of the sign could still recognize it.²¹⁸ A 1924 meeting set the background to yellow,²¹⁷ because no red material that resisted fading was available.²¹⁸ The first MUTCD in 1935 specified a 24 x 24 inch octagon with red or black letters on yellow.²¹⁷ The 1948 manual required all regulatory and warning signs to be reflectorized.²¹⁷ In 1954 the background changed to red with white lettering,²¹⁷ which matched the red of the traffic signal and gave "stop" one color everywhere.²¹⁸ (For the signal side of that story, see How a City Works: traffic lights.)

Today's standard US stop sign is 30 inches with a 10 inch legend, 35 inches on multilane expressways, 45 inches in oversize versions, and 24 inches at minimum.²¹⁸ To count as visible at night, its white must measure at least 35 and its red at least 7 on FHWA's retroreflectivity scale, with a contrast ratio of at least 3:1.²¹⁹ Minnesota's guidance on the 11th edition adds that a stop sign may not be fully covered by a differently shaped sign mounted on its back - the octagon has to stay readable from behind.²²⁰

What are the rules for street name signs?

What you see: A rectangle at the corner, usually white letters on green, the name in capital-and-lowercase, mounted above a stop sign or hung over the intersection on a mast arm.

Street name signs follow federal rules on letter size by road type. A summary of the 2009 MUTCD (Section 2D.43 in that edition's numbering) gives these minimums:²²¹

The names must be in mixed case - an initial capital, the rest lowercase - and the sign must be retroreflective or lit.²²¹ In a test on the then-unopened Capital Beltway, drivers preferred mixed-case lettering to all capitals.²²²

Four color schemes are allowed: white letters on green, blue or brown, or black letters on white.²²¹ Some cities have gone their own way anyway: Mesa, Arizona used ruby red, and San Jose used white on black until the 2010s.²²³ Minneapolis uses blue for snow emergency routes and green elsewhere.²²³ FHWA eliminated the deadline for replacing street name signs to meet retroreflectivity minimums, though the signs are still expected to meet those minimums under the agency's maintenance method.²¹⁹

The history goes back further than the MUTCD: a 1916 Iowa State College bulletin found that "by far the greater portion" of common enameled-iron street name signs were already made in white on blue.²²⁴

Why are some street signs blue instead of green?

What you see: A blue street name sign where the rest of the neighborhood uses green.

Blue is one of the four permitted color schemes, so a town can pick it for every sign.²²¹ Cities also use color to carry a second meaning, as Minneapolis does with blue snow emergency routes.²²³ SlashGear, a tech site, says blue signs often mark privately maintained roads such as those in gated communities or homeowners' associations;²²⁵ treat that as a common local habit, not a national rule.

Why are there so many parking signs on one pole?

What you see: A pole with five to eight small signs stacked vertically - street cleaning, permit parking, two-hour limit, tow zone, loading zone - that seem to contradict each other.

In US cities each parking restriction usually gets its own sign, so one curb space can end up with seven or eight signs stacked several feet high.²²⁶ Green lettering is used on permissive parking signs,²¹¹ and red on prohibitions such as NO PARKING ANY TIME.²²⁷ Reading a stack means working through every sign and finding the ones that apply at this hour on this day. The curbs section covers painted curb colors, which some places use alongside or instead of parking signs.

Brooklyn designer Nikki Sylianteng, after a $95 ticket, drew a grid alternative: one column per day of the week, green blocks for when parking is allowed, red for when it is not, black for loading hours.²²⁶ Los Angeles installed 100 of her signs downtown in 2015 for a six-month trial.²²⁶

In the federal manual, parking signs make up the R7 series. The 2003 edition's figure of No Parking signs runs from R7-1 NO PARKING ANY TIME through R7-8 reserved accessible parking to plaques such as R7-201 TOW-AWAY ZONE.²²⁷

In Boston

Boston piloted LED-lit street name signs at three Downtown Crossing locations in winter 2012; they were about 35 percent larger than the signs they replaced.²²⁸ BTD's 2016 sign guide sizes pole-mounted street name signs at 9 in (23 cm) tall under its spec A51, and mast-arm signs at 18 in (46 cm) tall and up to 72 in (183 cm) long under spec A50; the guide does not give colors or letter heights.²²⁹ Next door, Brookline kept raised-letter signs with black letters on silver, an exception to the green-and-white standard.²³⁰ In late 2005 Boston posted more than 100 blue-and-white "Evacuation Route" signs²³¹ - blue being the MUTCD color for evacuation routes.²¹¹

Elsewhere in the world

Most of Europe and many other countries follow the 1968 Vienna Convention, which uses a different shape grammar: red-bordered triangles for danger warnings, red-ringed circles for prohibitions, blue circles for mandatory instructions and rectangles for information.²³² The convention allows diamonds for warnings,²³² but the yellow diamond is mainly a habit of North America, Australia and Japan.

The Vienna stop sign is the same red octagon with white STOP, in English or the national language; a circle-with-triangle variant was dropped in a 2025 amendment.²¹⁸ Japan uses a red inverted triangle, Israel a raised-hand pictogram, and Bangladesh and Nepal omit the text.²¹⁸

Guide sign colors swap around too. Japan uses green on expressways and blue on ordinary roads.²³³ In the UK, many street name plates use David Kindersley's MoT Serif lettering, which was rejected for road signs.²²³ The fonts, codes and international systems are covered in Fonts, stickers and numbers on signs. For how roads and their rules are governed, see How a City Works: roads.

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13Fonts, stickers and numbers on signs

The short version: The lettering on US road signs is a government typeface nicknamed Highway Gothic, first published in 1948; a rival called Clearview was approved, withdrawn and reinstated within 14 years. The back of a sign can carry a punched or stamped label recording when it was made and installed, because agencies must keep signs bright enough to read at night. In the US, mile markers and exit numbers count distance across a state, and the red-white-and-blue Interstate shield dates to 1957. Abroad, Britain's Transport lettering, Germany's DIN 1451, Japan's bilingual signs and the 1968 Vienna Convention each tell their own story.

What font is used on US highway signs?

What you see: Plain, slightly rounded sans-serif lettering on nearly every US sign, sometimes tall and narrow, sometimes wide and heavy.

The official name is the FHWA Standard Alphabets; everyone calls it Highway Gothic. It was developed during World War II by the Public Roads Administration, and draft versions were used in 1942 on the road network around the Pentagon.²³⁴ It was published in 1948, reprinted in 1952, revised in 1966, 1977 and 2000; the 2000 revision added lowercase letters, which were formally allowed in 2004.²³⁴

A narrow series lets a long street name fit a short blade; a wide one reads from farther away. Series E(Modified), the thick white lettering on green freeway signs, got its weight from the era when legends were studded with button reflectors.²³⁴

The alphabet travels. Versions are used in Australia (under AS 1744:2015), Canada, New Zealand, Malaysia, Turkey, Brazil and the Netherlands, among others; Mexico and Saudi Arabia stopped using it in 2023.²³⁴

What happened to the Clearview font?

What you see: On some green freeway and street name signs, lettering with larger, more open lowercase letters than Highway Gothic.

Clearview was designed for mixed-case highway signs. Wikipedia credits Donald Meeker, James Montalbano, Christopher O'Hara and Harriet Spear.²³⁵ Its run with the federal government went like this:

The approval covers only positive contrast legends - light letters on a dark background, such as white on green - on guide signs.²³⁵ In terminating it, FHWA cited research finding that sheeting brightness is "the primary factor in nighttime legibility," plus misapplications that hurt uniformity.²³⁵ FHWA's report to Congress said Clearview signs run about 10 percent larger, require an add-on font license, and that "there are no known negative safety implications related to the termination."²³⁷ Even after reinstatement, FHWA "makes no recommendation or endorsement of the Clearview letter style."²³⁶

As of October 2026, where it stands is unclear. FHWA's interim approvals page lists IA-5 under terminated approvals issued under the 2009 MUTCD and says those have been incorporated into the 11th edition "either in whole or in part"; it lists IA-23 as the only current interim approval under the 11th edition.¹⁶⁰ The page does not say outright whether new Clearview signs are allowed under the 11th edition, which took effect January 18, 2024.²¹³

The 11th edition's own rule, in Section 2A.08, is that "all sign lettering, numerals, and other characters shall be of the Standard Alphabets" unless the manual provides otherwise, and that the letter forms "shall not be stretched."²¹⁴ Chapter 2A does not mention Clearview by name.²¹⁴

What do the stickers on the back of road signs mean?

What you see: On the back of a sign, a small sticker with a grid of punched holes, a stamped date, an agency name or a "property of" stencil, sometimes a barcode.

These are inventory labels. The Texas Department of Transportation's version is well documented. TxDOT requires a punch-coded sign identification decal on signs installed after August 15, 1980, placed in the lower left corner of the sign back.²³⁸ Its 12-row grid records the reflective sheeting manufacturers, the fabricator, the month and year of fabrication, and the month and year of installation; the fabricator punches rows 1 to 7 and the installer rows 8 to 12.²³⁸ The point is to trace materials that fail early and learn how long materials last, which informs when signs get replaced.²³⁸

A date on the back helps an agency meet the federal retroreflectivity rule below, since one accepted method is replacing signs when they reach their expected life.²¹⁹ No national label format turned up in the sources for this guide.

Why do signs glow in headlights, and why do they get replaced?

What you see: Signs that flare bright when your headlights hit them, next to faded, chalky signs that barely show up.

Sign faces use retroreflective sheeting, which sends light back toward its source - your headlights - so the sign appears to light up for the driver behind them. The 1948 MUTCD first required all regulatory and warning signs to be reflectorized.²¹⁷

The modern rule came later. A federal final rule was published December 21, 2007 and took effect January 22, 2008; it requires agencies to "use an assessment or management method" to keep signs at or above minimum retroreflectivity levels set in a table in the manual.²¹⁹ Accepted methods include visual nighttime inspection, measuring retroreflectivity, replacing signs at the end of expected life, blanket replacement of a whole area, and tracking control signs.²¹⁹ An agency complies by using a method, even if some individual signs fall below the minimum at any moment.²¹⁹ A 2012 rule set June 13, 2014 as the date to have a method in place and eliminated the replacement deadlines for guide and street name signs.²¹⁹

For a sense of the numbers (the signs section covers stop sign sizes): a stop sign's white must measure at least 35 and its red at least 7, with a contrast ratio of at least 3:1.²¹⁹ The FHWA page describes the 2009 edition's numbering; the 11th edition's section numbers were not confirmed.

Where does mile marker 0 start?

What you see: Small green vertical signs along a US highway with a number, sometimes with a route shield or direction.

These are reference location signs, the D10-1 series, with D10-1a for intermediate markers.²¹² Distance numbering increases northbound and eastbound, and "the zero-distance should begin at the south and west state lines."²¹² So where a state follows this guidance, mile 0 on a north-south route is where it enters the state from the south. Some states add finer markers: Missouri uses Emergency Reference Markers (D10-5) every 0.2 mile on Interstates;²¹² 0.2 mile is about 1,050 feet (320 m).

How are highway exit numbers decided?

What you see: "Exit 22" on a green guide sign, with a small numbered tab at the top.

Missouri's guidance says the route chosen for continuous distance numbering "should also have continuity in interchange exit numbering"²¹² - in other words, exit numbers follow the same count as the mile markers. Under mileage-based numbering, Exit 22 sits near mile marker 22, and a new interchange between two exits does not force renumbering everything downstream.

The 2009 MUTCD required every state to set up mile-based exit numbering.²³⁹ Massachusetts, which still used sequential numbers, announced its conversion in 2019 at an estimated cost of $2.8 million, about 90 percent of it federal safety money.²³⁹²⁴⁰ Crews started in western Massachusetts in fall 2020 and worked east; by February 2021, nine corridors were done, including I-90 from Boston to West Stockbridge, Route 3 from Braintree to Bourne and Route 24, with completion expected by summer 2021.²⁴⁰ Signs reading "Old Exit" with the former number stay up for at least two years after each conversion.²⁴⁰

Who designed the Interstate shield?

What you see: A shield with a red band on top reading INTERSTATE and a blue lower part with a white route number.

The Interstate route marker was approved by AASHO (now AASHTO) on August 14, 1957, combining designs submitted by Missouri and Texas.²²²²⁴¹ It was tested near the AASHO Road Test in LaSalle, Illinois.²²² The numbering plan, which mirrors the older US route system, was approved on September 10, 1957.²⁴¹ The shield is a registered trademark, number 835,635, registered September 19, 1967.²²²

The green of Interstate guide signs was also a test result. On the unopened Capital Beltway near Greenbelt, Maryland, 58 percent of drivers picked green over blue and black, and the color was approved in January 1958.²²² The same tests found drivers preferred mixed-case lettering to all capitals.²²²

In Boston

The federal rules in this section apply on Massachusetts roads as they do across the US. The Boston section covers the city's own street hardware. Massachusetts is a useful case for exit numbers because it changed systems in 2020 and 2021, as described above.²⁴⁰ For the road agencies behind these signs, see How a City Works: roads.

What is the Vienna Convention on road signs?

What you see: In Europe and much of the world, red-bordered triangles for hazards, red-ringed circles for bans, solid blue circles for instructions, and mostly symbols instead of words.

The Vienna Convention on Road Signs and Signals is a UN treaty signed on 8 November 1968 that entered into force on 6 June 1978; it had 71 parties as of September 2024.²³² It sorts signs into lettered categories:²³²

The stop sign, B2a, is a red octagon with white STOP.²¹⁸ The US is not a party, and neither are Ireland, Iceland, Malta, Japan, China, Israel or Malaysia.²³²

What font are UK road signs in?

What you see: British signs in rounded sans-serif lettering: blue motorway signs, green primary route signs, white local signs, red triangles with black pictograms.

Designers Jock Kinneir and Margaret Calvert created both the signs and their lettering. The Anderson Committee was formed in 1957 to sign Britain's first motorway, the Preston Bypass, which opened in 1958.²⁴² The Worboys Committee, chaired by Sir Walter Worboys of ICI, then published its report on all other roads in July 1963.²⁴² The system was implemented through the Traffic Signs Regulations and General Directions (TSRGD) 1964 and became law on 1 January 1965, adopting continental shape and color conventions from the 1949 UN Protocol.²⁴²²⁴³

The Transport typeface was designed between 1957 and 1963; Transport Heavy is used for dark letters on light backgrounds and Transport Medium for light on dark, and a separate face called Motorway handles route numbers.²⁴⁴ Both are based on Akzidenz Grotesk.²⁴³ Transport is also used in Ireland, Iceland, Portugal, Hong Kong, Malaysia, Malta and Spain, among others, and a 2012 redraw, New Transport by Calvert and Henrik Kubel, became the GOV.UK website font.²⁴⁴ The girl in the Children Crossing sign is based on an image of Calvert as a child.²⁴³

What font do German road signs use?

What you see: Condensed, geometric sans-serif lettering on German road signs.

DIN 1451 is Germany's standard typeface: a preliminary sheet appeared in 1931 and the official standard in 1936, and a 1938 order required it on the Autobahn.²⁴⁵ It comes in Mittelschrift (medium) and Engschrift (condensed); a wide Breitschrift has not been used since the early 1980s.²⁴⁵

License plates used DIN 1451 from 1956 to January 1995.²⁴⁵ They switched to FE-Schrift, designed 1978-1980 by Karlgeorg Hoefer for the Federal Highway Research Institute to resist forgery and suit machine reading; it has been on plates since 1994 and fully replaced DIN 1451 there by 2000.²⁴⁶ The two sources give slightly different switchover dates.

Why is Japan's stop sign a triangle?

What you see: A red downward-pointing triangle reading 止まれ, often with STOP underneath.

Japan is not a Vienna Convention party and keeps its own system.²³² Its stop sign was a yellow octagon from 1950 and a red octagon from 1960 before becoming a red inverted triangle in 1963.²³³ Bilingual stop and slow signs date from 2017,²³³ part of a rollout that began in July 2017 because of growing numbers of foreign visitors ahead of the Tokyo Olympics.²⁴⁷

English text on Japanese signs has used the Vialog typeface since 2014.²³³ Expressway guide signs are green and ordinary-road direction signs blue, and warning signs show deer, rabbits, monkeys and raccoon dogs (tanuki).²³³

What does the kangaroo sign mean?

What you see: A warning sign with a black kangaroo silhouette on a rural Australian road.

It warns that kangaroos may cross. In New South Wales it is a standard sign available to councils, coded W5-29 "Kangaroos (Symbolic)," with AS 1742.2 as its technical reference and sizes from 600 to 1,200 mm (about 24 to 47 inches).²¹⁶ The W prefix matches the US habit of coding warning signs with W.

What do brown road signs mean?

What you see: White lettering and symbols on brown, pointing to a park, historic site, museum or attraction.

In the US, brown is the background for guide signs to recreational or cultural points of interest,²¹¹ and the trapezoid shape is reserved for the same family plus national forest routes.²⁰⁹ In England, DfT Circular Roads 1/91 (January 1991, replacing Circular 3/86) set the rules: tourist signs are "displayed in white on a brown background" and are not meant as advertising.²⁴⁸ An attraction applies for one; Durham County Council, for example, makes the applicant pay all costs and requires compliance with TSRGD and Chapter 7 of the Traffic Signs Manual.²⁴⁹

Elsewhere in the world

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14Curb colors, curb ramps and the bumpy yellow tiles

The short version: In California, a painted curb is a legal parking code set by state law: red, yellow, white, green and blue each mean something specific, and local ordinances fill in the hours.²⁵⁰ Many other places, including New York State, do not use curb color to set parking rules at all and rely on signs.²⁵¹ The sloped cut at a corner is a curb ramp, and the panel of small bumps at its foot is a detectable warning surface that tells a blind pedestrian the street starts here.²⁵²²⁵³ Those bumps are often yellow because yellow is easy to see for people with partial sight, though US federal rules only ask for strong light-dark contrast.²⁵⁴²⁵³

What do the different curb colors mean?

What you see: A curb painted solid red, yellow, white, green or blue, sometimes with stenciled words or a time limit.

California has the clearest written code. Section 21458 of the California Vehicle Code assigns each color a meaning:²⁵⁰

The state code sets the meanings but no time limits. Under subdivision (b), local ordinances decide the days and hours when the colors apply.²⁵⁰ That is why the same color behaves differently from city to city. Los Angeles allows 5 minutes in a white zone and Long Beach 2 minutes (taxis excepted). San Diego's yellow zones apply 6 a.m. to 6 p.m. except Sundays and holidays, and its green zones allow 15 to 20 minutes.²⁵⁵ In Seattle, some white curbs are reserved for police or fire vehicles.²⁵⁵

The practical rule: the color tells you the category, and the sign or stencil nearby tells you the hours. Where the two seem to disagree, read the sign.

Do curb colors mean the same thing everywhere?

What you see: A painted curb in a city that is not in California, with or without a sign.

No, and the sources disagree about how common the system is. A KXAN explainer calls the colors "largely the same throughout the U.S." but still advises drivers to read the posted signs.²⁵⁵ New York State's version of the traffic-control manual takes the opposite position. Its Section 3B.23 says "A colored curb shall not be used to convey parking regulations." Signs are the primary method there, and word markings on the curb may only repeat a general prohibition already in state law.²⁵¹

New York gives two reasons that apply well beyond New York: curb paint is often hidden under snow and ice, and some visually impaired road users find curb colors hard to tell apart.²⁵¹ In a snowy city, a rule that disappears for four months a year is not much of a rule, so signs carry the legal weight.

The national manual is softer than New York's. In the 11th edition (2023), Section 3B.18 says parking rules should generally be set with standard signs, because "yellow and white curb markings are frequently used for curb delineation and visibility," and that where snow and ice often hide curb markings, signs should go with them.³ Unmarked curb paint may stand alone only to show a general prohibition in state law, such as near a stop sign, hydrant, driveway or crosswalk, and local agencies "may prescribe special colors for curb markings to supplement standard signs."³

In Boston: what do painted curbs mean?

What you see: A yellow-painted curb near a hydrant or at a corner, usually with a sign nearby.

No published Boston curb-color policy turned up in the research for this guide. Boston, like most of New England, puts its parking rules on signs. Yellow paint near hydrants and corners is a common sight, but treat it as a reminder, not a code, and go by the posted sign. For how the city's parking and street rules fit together, see How a City Works: the rules.

Boston's Traffic Rules and Regulations (effective March 1, 2025) define an "official street marking" as any painted line, legend or marking authorized by the Commissioner of Transportation, and require drivers to obey official markings as well as signs.²⁵⁶ The sections reviewed for this guide set no meanings for curb colors.²⁵⁶

Why is there a slope cut into the curb at the corner?

What you see: A sloped concrete cut through the curb at a corner or crosswalk, usually with a bumpy panel at the bottom.

That is a curb ramp, a short slope that lets wheelchair, stroller, walker and cart users get between the sidewalk and the street without a step. A blended transition does the same job with a gentle slope instead of a distinct ramp.

In the US, the federal design rule for public streets is the Access Board's Public Right-of-Way Accessibility Guidelines (PROWAG). The final rule was published August 8, 2023, and took effect September 7, 2023.²⁵²²⁵⁷ It requires a curb ramp or blended transition at every pedestrian crossing (R304) and a detectable warning surface at curb ramps (R305).²⁵²

Two details explain why your corner may not match the rule:

• PROWAG covers new construction fully. Altered facilities must comply "to the maximum extent feasible," and existing facilities need not comply unless they are altered (R101.4).²⁵² A repaving or reconstruction project is often what brings a corner up to date.
• PROWAG becomes enforceable only when the US Department of Justice and Department of Transportation adopt it as standards, with or without changes.²⁵⁷ As of the 2023 summaries, that adoption was "anticipated" in 2024.²⁵²

Adoption has come in pieces. On December 18, 2024, DOT adopted PROWAG into its ADA standards, effective January 17, 2025, but only for new construction and alterations of transit stops in the public right-of-way; the General Services Administration had adopted it in July 2024.²⁵⁸ As of a February 20, 2026 letter from seven members of Congress asking for a status update, the Justice Department had not adopted it for streets and sidewalks generally.²⁵⁹

In Boston, the city's sidewalk standards (November 2013, revised January 2014) say pedestrian ramps must be concrete, with no brick or specialty pavers, and must have a 2-foot (about 61 cm) tactile warning strip at the base.²⁶⁰ That rule set off a long fight on Beacon Hill, told in the sidewalks section under brick sidewalks. For the street design side of corners and crossings, see How a City Works: roads.

What are the bumps at the bottom of a curb ramp called?

What you see: A rectangular panel of small flat-topped bumps, usually yellow, brick red or dark gray, at the foot of a curb ramp or along a train platform edge.

These are detectable warning surfaces, made of rows of truncated domes: bumps with the tops sliced flat. A cane tip or a shoe sole picks up the change in texture, which tells a blind or low-vision pedestrian that the sidewalk is about to end at a street or a drop-off.

The 2010 ADA Standards, Section 705.1, set the dome geometry:²⁵³

Where the domes are required has shifted over the years, which is why older ramps often have none:

• Detectable warnings were required at rail platform edges from 1991. The curb-ramp requirement was suspended for study in 1994 and reinstated in 2001.²⁶¹
• The Justice Department's 2010 ADA Standards do not require them on curb ramps. The Department of Transportation's 2006 ADA Standards do require them on curb ramps at public transportation facilities (406.8), across the full width of the ramp and either its full depth or at least 24 inches (61 cm) back from the curb.²⁶²
• The Federal Highway Administration has encouraged them on curb ramps in federally funded projects since a May 2002 memorandum.²⁶²
• PROWAG (2023) requires them at curb ramps, and also where a sidewalk crosses a driveway controlled by yield signs, stop signs or signals (R305.2.8). It does not use them to mark edges at roundabouts (R306.4).²⁵⁷

Why are the bumps yellow?

What you see: Bright yellow bumpy panels, sometimes next to older red or gray ones.

Yellow is there for people who can see a little. Many people with low vision can spot a bright panel before they reach it, and a high-contrast color lets them use their eyes as well as their feet. Japan's tactile blocks "were originally grey" and were changed to yellow so that people with "weak or partial sight" could see them more easily.²⁵⁴

US federal rules do not name a color. They require light-on-dark or dark-on-light contrast.²⁵³ So a dark panel on pale concrete, or a pale panel on dark asphalt, can meet the federal standard. Some states go further. California's Building Code (2025, Section 11B-705.1.1.3.1) says "Detectable warning surfaces shall be yellow and approximate 33538 of SAE AMS-STD-595A," a specific federal color standard, at curb ramps, islands, platforms, bus stops and more. Existing detectable warnings at curb ramps, islands and cut-through medians may instead meet a 70% contrast option.²⁶³

Boston defaults to pale yellow and uses brick red where the sidewalk is brick in a historic district.²⁶⁰ When Beacon Hill opponents of the city's ramp plan proposed a terra cotta panel on a gray ramp, city officials said gray gives too little contrast.²⁶⁴

What are the yellow striped and dotted tiles in Japan?

What you see: Lines of yellow tiles across Japanese sidewalks and station floors. Some have dots, and some have long raised bars that form a path.

These are tenji blocks (tenji is the Japanese word for braille), and they are the original tactile paving. Seiichi Miyake, born in 1926 in Kurashiki, Okayama Prefecture, invented them in 1965 with his own money to help a friend who was losing his sight. The first installation, by the most widely cited account, was on March 18, 1967, at a school for the blind in Okayama City. A Google Doodle marked that anniversary in 2019. Miyake died in 1982.²⁶⁵

Sources disagree on the first date. The Japan Up Close feature dates the first 230 blocks, set near a crosswalk by the School for the Blind in Okayama, to March 1965.²⁵⁴ Even a travel blog that tells the story calls the first-site detail "worth double-checking."²⁶⁶

The two block types:

Source for the table: JRPass.²⁶⁶ Japanese warning dots are about 22 mm (0.87 in) across and 5 mm (0.2 in) high.²⁶¹

Adoption came in steps. Japan National Railways made the blocks mandatory by 1975, and cities had adopted them by 1985.²⁵⁴ More than 50 pattern variations caused confusion until a national standard, JIS T 9251, in September 2001.²⁵⁴ A 1994 law required them in buildings over 2,000 m² (about 21,500 sq ft), replaced by a broader law in 2006.²⁶¹ The blocks have spread to Korea, Taiwan, China, and parts of Australia, Europe and the US.²⁵⁴

The big difference a visitor notices: Japan lays continuous guidance paths of bar blocks along sidewalks and through stations, while the 2010 ADA Standards define only the warning domes, with no directional bars.²⁵³

What do the different bumpy paving slabs mean in the UK?

What you see: Square paving slabs with rows of flat bumps at crossings, usually red or buff, or slabs with ridged bars at the top and bottom of steps.

The UK has the most detailed system, set out in the Department for Transport's Guidance on the use of tactile paving surfaces (December 2021, replacing the 1998 guidance). Unusually, color carries meaning: red is reserved for controlled crossings.²⁶⁷

Source for the table: DfT 2021.²⁶⁷

Elsewhere in the world

The three systems in this section line up like this:

For curb colors, New York State bars using color alone to convey parking rules, while California writes them into statute.²⁵¹²⁵⁰

Internationally, ISO 23599:2019, Tactile walking surface indicators, specifies two types - attention patterns and guiding patterns - and says it does not replace national rules.²⁶⁸ Australia follows the same split under AS 1428.4.1: Sunshine Coast Council's guidance calls for warning indicators at least 600 mm (about 24 in) deep across the line of travel, set 300 mm (about 12 in) back from the hazard, and directional indicators laid along the center line of the path.²⁶⁹

What are those short posts on the sidewalk?

What you see: Short, sturdy posts along the sidewalk edge, in front of a building or across a plaza. They may be bare steel, concrete or decorative cast iron, and some lift out or sink into the ground.

These are bollards. Ordinary traffic bollards guide or block cars and protect corners, doorways and pedestrians. Security bollards are built and crash-tested to stop a truck. The two can look the same, because crash-rated bollards use high-strength steel and reinforced foundations that are often hidden under a decorative cover.²⁷⁰

Security bollards are rated by crash test. The current standard is ASTM F2656, and many specifications still cite the older US Department of State K-ratings:²⁷⁰

An "M50-P1" bollard, then, stopped the test truck at 50 mph within about a meter. You cannot tell a rated bollard from a decorative one by looking, and nothing about a bollard's appearance tells you how deep its footing goes.

The word also means a short, thick post on a ship or dock for securing mooring lines; according to a bollard maker's history, it first appeared in the Oxford English Dictionary in 1844 and probably comes from "bole," a tree trunk.²⁷¹ In the 17th and 18th centuries it became common to half-bury decommissioned cannon barrels as posts on wharves and streets.²⁷¹ One survivor in Faversham, England, a late 17th or early 18th century cannon used as a bollard, is a Grade II listed structure.²⁷² In London, cannon taken from French ships after Trafalgar in 1805 were reused as bollards, and replicas in the same cannon shape are still made.²⁷³

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15Sidewalk stamps, old rails and street archaeology

The short version: A sidewalk is a dated document if you know where to look. Names, years and "WPA" pressed into concrete record who poured it and when, and New Deal crews left many of these in the late 1930s.²⁷⁴ Iron boot scrapers by the door, faded ads on brick walls, granite blocks and trolley rails showing through asphalt are leftovers from the horse, streetcar and hand-painted-sign eras.^275276277 Signs saying "Private Way" or "Right to pass by permission" are legal notices about who owns the ground under your feet.²⁷⁸²⁷⁹

Why is there a name or a date stamped in the sidewalk?

What you see: A small rectangle or oval pressed into one concrete sidewalk panel, with a company name, a year, or both.

That is a contractor stamp. Private contractors in the early 20th century often pressed their name, and sometimes the year, into fresh concrete when they finished a job.²⁷⁴ The stamp works as a signature and, for later readers, as a date. If a block has panels with different stamps, you are looking at a patchwork of repairs from different years and different crews.

A stamp dates the panel it sits in, not the whole sidewalk. Neighboring panels may be older or newer, and a stamp with no year can still be dated roughly by which companies were working in a city when.

Some cities have made the stamp a rule. WUWM reported in 2016 that Milwaukee sidewalks are required to carry the installation date and the contractor's name, a practice dating to the boom in concrete sidewalks around 1900; a Milwaukee Public Museum curator said the city needed to know who built each sidewalk so it could hold contractors to repairs.²⁸⁰ In Toronto, blogTO reported in 2013 that new stamps must follow a strict set of rules on size and placement.²⁸¹

What does "WPA" stamped in the concrete mean?

What you see: A stamp reading "WPA" with a year in the late 1930s or early 1940s, sometimes with "USA" or a project number.

WPA is the Works Progress Administration, the New Deal jobs program. Its workers built many sidewalks and "often" pressed stamps into the fresh concrete, following the private contractors' habit.²⁷⁴ The Living New Deal project records surviving examples in Clayton and Tucumcari, New Mexico; Knights Landing, California (dated 1940); San Leandro, California; Warwick, Rhode Island; and New Orleans. It also lists WPA sidewalk work in Lordsburg, New Mexico (1936 and 1938) and Provo, Utah (1939), though without mentioning stamps there.²⁷⁴ In Providence, WPA plaques survive, one of them set into a manhole cover at Mount and Slater Avenues.²⁷⁴

A WPA stamp means that piece of sidewalk has carried foot traffic for more than 80 years. If you find one, the Living New Deal database is the place to check whether it is already recorded.

Why does Boston have brick sidewalks?

What you see: Red brick sidewalks, often uneven and laid in patterns, edged with long granite curbstones, in neighborhoods like Beacon Hill, the South End and Back Bay.

Brick is part of how Boston's historic neighborhoods look, and residents have defended it for a century. The Beacon Hill Civic Association formed in 1922 to oppose paving over the neighborhood's brick sidewalks.²⁸²

Brick also makes a bumpy surface, and state and ADA codes require walking surfaces without variations over a quarter inch (about 6 mm).²⁸² In 2010 the city banned "City Hall pavers," a molded brick made by Stiles and Hart of Bridgewater, and adopted a policy of "no net new brick."²⁸²

Under the city's Sidewalk Construction and Rehabilitation Standards (November 2013, revised January 2014):²⁶⁰

You can see the policy at work in individual permits. In 2013 the Beacon Hill Architectural Commission approved replacing more than 800 sq ft (about 74 m²) of brick on Joy Street with wire-cut brick for a smoother surface.²⁸³ A sidewalk application for 10 Walnut Street proposes wire-cut "Beacon Hill Blend" pavers and a granite curb to "match existing," with a 5-inch (13 cm) reveal, the height of curb face showing above the gutter.²⁸⁴

The granite has a local history. Large-scale granite quarrying in Quincy, south of Boston, began in 1825, when Solomon Willard chose West Quincy stone for the Bunker Hill Monument, and the Granite Railway was built in 1826 to haul it; the last active Quincy quarry closed in 1963.²⁸⁵ Granite was used for paving blocks and curbing across New England, especially in the 19th century.²⁸⁶ Granite is still Boston's standard curb: as of 2026 the Public Works design standards include details for resetting existing granite curb and specifications for new straight and curved granite curb.²⁸⁷

The Beacon Hill curb ramp fight

What you see: Concrete curb ramps with brick-red tactile panels at corners in the South End, Back Bay or Bay Village, and in places on Beacon Hill, older corners that have none.

In 2013 the city proposed 259 curb ramps with tactile strips on Beacon Hill.²⁶⁴ On December 19, 2013, the Beacon Hill Architectural Commission voted 3-2 to reject the plan's poured concrete ramps and plastic composite panels.²⁸³ Opponents wanted granite ramps.²⁶⁴

The city's numbers, as reported by the Boston Globe in February 2014: concrete ramps averaged about $6,000 each, granite would cost more than four times as much, and the plastic tactile strips cost about $300.²⁶⁴ The color question went back and forth. The city first proposed yellow strips, then terra cotta. Opponents would accept terra cotta only on a gray ramp, and city officials said gray gives too little contrast for people with low vision.²⁶⁴ Meanwhile the South End, Bay Village and Back Bay had already settled on concrete ramps with brick-colored strips.²⁶⁴

The dispute set two public goods against each other: a historic streetscape and access for wheelchair users and blind pedestrians. Residents and the commission argued for materials that match the district, and the city argued for cost and visibility. The federal rules behind the ramps and the bumps are explained in the curbs section.

The fight went to court. In August 2014, on the day city workers began installing the first of more than 250 ramps, the Beacon Hill Civic Association sued the city in Suffolk Superior Court, arguing that the work needed state and commission approvals it had not received.²⁸⁸ The case was settled in February 2018. Under the agreement, Public Works can keep installing ADA-compliant ramps in the district, uses red cast-iron tactile pads instead of plastic ones with the Civic Association paying the difference in cost, and presents its ramp plans for the district at least once a year.²⁸⁹

What is the metal blade next to old front steps?

What you see: A small iron blade or frame beside a front step, sometimes built into the railing or set into a niche in the wall.

That is a boot scraper, also called a door scraper, mud scraper or décrottoir. They appeared at the end of the 18th century, when streets were dirt and horse manure, and people scraped their shoes before going indoors.²⁷⁵ Some that stood out on the footpath were banned as tripping hazards and moved into niches in the facade, and many were later removed or salvaged for scrap. Well-known examples survive at 10 Downing Street in London, Goethe's house in Weimar and in Greenwich Village.²⁷⁵

In Boston, "most historic houses" on Beacon Hill have one.²⁷⁵ Locals call them "mudders." Examples include 54 Pinckney Street, where Nathaniel Hawthorne roomed around 1840; 98 Pinckney; 50 Chestnut Street, the Francis Parkman house (1824); 46 Chestnut (early 1900s); 1 Louisburg Square, where the scraper is built into the railing; and 11 West Cedar Street.²⁹⁰

Why are blue mailboxes disappearing?

What you see: A blue US Postal Service collection box with a curved top on a corner, or a patch of newer concrete where one used to stand.

The first cast-iron street collection boxes were mounted on light posts in Boston, Philadelphia and New York in the 1850s, and the boxes "weren't always blue."²⁹¹ Their number has fallen sharply because the Postal Service removes boxes that collect little mail. A 1974 guideline said boxes averaging fewer than 25 pieces a day should be considered for removal.²⁹¹ Boxes have also shifted from residential corners toward business districts.²⁹²

The counts do not agree between sources. One report puts the peak at 365,000 boxes in 2000 and just under 154,000 by 2015.²⁹¹ Another says about 218,000 had been removed since 1985, leaving just under 177,000 in September 2009.²⁹² Those figures do not fit together cleanly, so treat them as approximate. Both describe the same trend: well over half the boxes are gone.

Removals became news in 2020. After photos of removed boxes spread on social media, USPS paused removals until after the November election.²⁹¹

In California, a white curb next to a mailbox lets drivers stop to deposit mail.²⁵⁰

According to Wikipedia's history of post boxes, US collection boxes were first painted red or green, switched to dark green in 1909 to avoid confusion with fire equipment, and turned olive drab after World War I, when the Army donated surplus paint. In 1955 they became red, white and blue, and in 1971 the new Postal Service adopted the dark blue used today.²⁹³

What does a "Private Way" sign mean in Boston?

What you see: A street sign or homemade sign reading "Private Way," sometimes "Private Way - Dangerous - Pass at your own risk," usually on a narrow side street.

In Boston, a private way is a street the city has not accepted as public. On a private way, residents are responsible for all street and sidewalk maintenance and for clearing snow. The city may plow in emergencies "at their discretion," collects trash only if city vehicles can safely get in and out, and maintains only "accessible" city-owned streetlights. Owners set and enforce parking.²⁷⁸ The Public Works Department's "street book" records whether a given street is public or private.²⁷⁸

The sign does two jobs: it warns drivers and walkers that the city does not maintain the surface, and it asserts the owners' rights over the way. If a pothole on a private way needs fixing, the neighbors fix it. For reporting problems on public streets, see How a City Works: 311.

What does "Right to pass by permission" mean?

What you see: A small brass plaque in the pavement or a sign at a walkway or plaza entrance reading "Right to pass by permission and subject to control of owner" or "Private property."

These notices exist because of the prescriptive easement: in many US states, if the public openly crosses private land for long enough without permission, it can gain a legal right to keep crossing. A posted notice turns the crossing into permitted use, which stops that clock.

The wording depends on the state. In California, Civil Code Section 1008 signs read "Right to pass by permission and subject to control of owner: Section 1008, Civil Code." The owner must post them at each entrance, or at intervals of no more than 200 feet (61 m).²⁷⁹

Massachusetts does it differently. Under General Laws chapter 187, section 3, an owner can prevent anyone from gaining an easement by use by posting notice "in a conspicuous place upon the premises for six successive days," or by serving notice on specific people. A certificate is then recorded at the registry of deeds within three months.²⁹⁴ So in Boston, the legal act is the posting and the recording, and a permanent plaque is not required by that statute.

What are the faded painted ads on old brick walls?

What you see: Faded lettering on an old brick wall advertising a product, store or hotel long gone, sometimes with two or three older ads showing through each other.

These are ghost signs: hand-painted wall advertisements that have weathered, or that reappeared when a neighboring building or billboard came down. A UK lettering studio's history says British examples are mainly 20th-century. They were painted in oil-based paint with hog's-hair brushes, and the designs were often transferred to the wall by "pouncing," dabbing powder through a perforated paper pattern. Billboards placed over them later protected some from the weather.²⁷⁶

"Ghost sign" is a recent term. A wall where layers of lettering overlap is called a palimpsest, a usage credited to Bob Allen. Ghost signs usually have no legal protection, so they disappear when walls are repainted or demolished.²⁷⁶

In the US the painters were called "wall dogs," and painted wall ads were most common in the decades before the Great Depression, according to Wikipedia's summary of reporting in the New York Times (2005) and the Star-Ledger (2012). The signs were painted in oil-based house paint that most likely contains lead, which helps it stay stuck to the brick.²⁹⁵

In Boston, city officials do not formally track ghost signs but estimate there are hundreds, according to WBUR in May 2026. That year a faded sign for the lumber firm Holt & Bugbee at 90 Canal Street in the West End was repainted, paid for by the company ($51,000) with the West End Museum as a partner; the same wall carries older lettering for J.F. Folsom Wholesale Confectioner and Bossom and Cuff Parlor Furniture.²⁹⁶

Why are there old trolley tracks showing through the road?

What you see: Pairs of steel rails, or the outline of them, showing through cracked asphalt or exposed in a roadwork trench, on a street with no trolley service.

These are streetcar rails left in place when a line switched to buses. Rails were often paved over rather than dug up, so they stay buried until a utility crew cuts a trench (see work zones) or the asphalt wears thin.

Two local cases show the pattern. In June 2016, tracks uncovered under Arsenal Street in Watertown belonged to the Watertown Square-Central Square line, whose last trolley ran on June 16, 1950. The local paper reported that they "will likely be removed."²⁷⁷ In Roslindale, tracks were exposed on South Street on August 1, 2014, in front of Wallpaper City, and a 1948 city archives photo shows the tracks.²⁹⁷

For how Boston's transit network grew and shrank, see How a City Works: transit.

Is that cobblestone or Belgian block?

What you see: A street, gutter strip or crosswalk paved with granite blocks, bumpy underfoot, sometimes peeking out where asphalt has worn away.

Almost always, what people call cobblestones are setts: broadly rectangular stones quarried and worked into shape, usually granite. A cobblestone is a small, naturally rounded rock. Setts gave horses grip on hills, and in the US they are also called Belgian block.²⁹⁸

New York's history shows the switch. Cobblestone, untooled and rounded, was used there until about 1860. Belgian block, tooled granite, was introduced in 1852 and became general after 1859. The "Manhattan standard" block of about 4 by 7 inches (10 by 18 cm) dates from 1912 to 1938. Whether the stone really came from Belgium is "unclear."²⁹⁹ US sett streets survive in the West Village, SoHo and TriBeCa in New York, Germantown Avenue in Philadelphia, Shockoe Slip in Richmond and Fells Point in Baltimore.²⁹⁸ A common story says such stones arrived as ship ballast. In Portland, Oregon, at least, the blocks are local basalt, not ballast.²⁹⁸

In Boston

Boston rewards a slow walk. On Beacon Hill, look for boot scrapers at many older front steps and wire-cut brick replacing older, rougher brick.²⁷⁵²⁸³ At corners in the South End, Back Bay and Bay Village, the brick-red tactile panels on concrete ramps are the result of the city's historic-district rule.²⁶⁴ Some of the first US street collection boxes went up in Boston in the 1850s.²⁹¹ Trolley rails have resurfaced in Roslindale and in neighboring Watertown.²⁹⁷²⁷⁷ And on narrow side streets, a "Private Way" sign means the neighbors, not the city, own the plowing.²⁷⁸

Elsewhere in the world

Boot scrapers are an 18th- and 19th-century habit on both sides of the Atlantic, from London to Weimar.²⁷⁵ British ghost signs are mostly 20th-century and rarely protected.²⁷⁶ Legal notices against public rights of way vary by state even within the US, as the California and Massachusetts rules show.²⁷⁹²⁹⁴ In the UK, the charity mySociety runs FixMyStreet, which lets people send street problems to their council almost anywhere in the country. As of July 2015 reports went to councils as plain-text emails or through the Open311 standard, and 10 of about 430 councils refused them.³⁰⁰

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16Reading a Boston street

The short version: One Boston block can hold objects from half a dozen owners: city Public Works streetlights, a Fire Department alarm box, Eversource manholes, National Grid gas, MBTA signs and a Bluebikes dock. Much of what makes the city look like Boston - gas lamps, brick sidewalks, granite curbs, the Freedom Trail's red line - is governed by historic-district rules as much as engineering. When something is broken, BOS:311 is the front door, and every report becomes a public ticket. In winter, posted snow emergency arteries and the space saver custom decide where you can park.

Who owns what on a Boston street?

What you see: A streetlight, a red fire alarm box, manhole covers stamped with different names, a signal pole, a bike-share dock and parking signs, all within a few steps of each other.

Boston splits the street among city departments, state agencies and private utilities, and the split is not always obvious even to the agencies. When CBS Boston asked who owned cracked streetlights leaning over Gallivan Boulevard in Dorchester, the answer turned out to be Eversource, on a road MassDOT took over from DCR in 2009 - and MassDOT itself first told reporters the road belonged to DCR.³⁰¹

Public way versus private way matters more than most residents realize. On a public way the city handles maintenance, cleaning, plowing and city-owned streetlights. On a private way the abutters are responsible, and utilities must get a city permit before working on public ways; for private ways the city only asks them to notify residents 7 to 10 days ahead.²⁷⁸

PWD's lighting plant alone is large: 19 fixture types, about 18 million feet of cable, 1,600 control boxes and 32,000 manhole pull boxes.³⁰² The city counts about 71,000 streetlights in all, a figure that includes its gas lamps and the red fire-alarm lights.³⁰²

The water side is the Boston Water and Sewer Commission's. Its crews inspect manholes and clean catch basins, and the city's open-data hydrant layer is maintained by the commission.³⁰⁷⁵⁹ Traffic signals are installed by the Boston Transportation Department (BTD).³⁰⁸ BTD also has its own Sign Shop. Its 2016 sign guide refers sign makers to the shop and notes that the shop does not manufacture or replace signs hung on traffic signal mast arms; contractors supply those when signals are installed or upgraded.²²⁹

Boston's underground electrical system dates to the late 1880s,³⁰³ which is part of why its covers look so varied. For how power and gas reach the street, see the sister guide's power section.

What is the red box on a pole with a white handle?

What you see: A red cast-iron box on a red pedestal or a utility pole, often under a red lamp, with a white pull handle.

This is a street box on the Boston Fire Department's fire alarm telegraph, switched on April 28, 1852, more than 20 years before Bell's telephone patent.⁶⁹ Boston has about 1,250 street boxes plus about 1,200 master boxes tied to schools, hospitals, libraries and other public buildings.⁶⁹ Each box carries a number that identifies its location, and that number is what dispatchers see.⁶⁹ The boxes kept working during the June 2024 statewide 911 outage.⁶⁹

They work. Pull one only for a real fire or emergency. The full story - the history, the 1983 plan to remove them that never happened, and which other cities still use boxes - is in the fire hardware section.

Why are Boston's gas lamps lit during the day?

What you see: Black colonial-style lanterns on posts with a soft, flickering glow, day and night, mostly on Beacon Hill and also in parts of Back Bay, Bay Village and Charlestown.

These are real gas lamps burning natural gas. Boston has about 2,800 of them, and the Beacon Hill Civic Association area holds "just under half."³⁰⁹ They burn around the clock, which is why you see them glowing at noon.

They are expensive and contested. In 2020 reporting, the lamps cost at least $200,000 a year to maintain and at least $1 million a year in gas, and the city set aside $400,000 for a design-build study with a pilot planned on Temple Street.³⁰⁴ In 2022, Chief of Streets Jascha Franklin-Hodge said, "Our plan is to replace all of the gas lights in Boston with LEDs," citing fuel costs of nearly $1 million a year and emissions comparable to more than 1,000 cars. The first LED replica went up on Shawmut Street in Bay Village.³⁰⁹ Supporters of the gas lamps argue on historic-character grounds; the city argues on cost and emissions.

On Beacon Hill, street lights are among the few pieces of "street furniture" the Architectural Commission allows, and they "shall be subject to Commission review and shall be in keeping with the architectural and historic character of the District."³¹⁰ The guidelines do not mention gas specifically.

How many lamps are in each neighborhood is surprisingly hard to pin down: an October 2025 BOS:311 request asking how many gas lamps are in the Back Bay and Beacon Hill area was still open as of October 2026.³¹¹

Why are some Boston sidewalks brick and others concrete?

What you see: Red brick sidewalks, some heaved by tree roots, in Beacon Hill, the South End, Back Bay and the North End. Elsewhere, plain concrete. Some walks have a concrete strip down the middle with brick along the curb.

Brick is mostly a historic-district surface. Under PWD's sidewalk standards (Nov 2013, revised Jan 2014), all new sidewalks must be concrete. In historic districts, existing brick is rebuilt with wire-cut brick "on a bed of asphalt or concrete," and small patches of about 2 ft x 2 ft (60 cm) may use matching brick.²⁶⁰

That concrete strip has a reason. In historic districts, sidewalks wider than 5 ft (1.5 m) keep a concrete path of travel, which may have a brick strip along the curb, and "In no case shall the concrete portion (path of travel) of the sidewalk be less than 4 feet" (1.2 m).²⁶⁰ The smoother surface is for wheelchairs, strollers and anyone who trips easily.

Curb ramps must be concrete: "brick or other specialty paver ramps will not be allowed." The bumpy tactile warning strip at the bottom is normally pale yellow, but brick red where the sidewalk is brick in a historic district.²⁶⁰

The fight is old. The Beacon Hill Civic Association formed in 1922 to oppose paving over brick sidewalks, and in 2010 the city adopted a "no net new brick" policy and banned the molded "City Hall pavers."²⁸² Preservationists value the brick as part of the district's character; accessibility advocates have long objected to its uneven surface. The sidewalks section tells the story of the Beacon Hill curb ramp fight.

What are the long gray stones along the curb?

What you see: Pale gray stone curbstones with squared tops along most older Boston streets, sometimes chipped or patched with an inset piece.

These are granite curbs. On Beacon Hill, even curb repairs go before the Architectural Commission. In July 2025 it approved an application for 78 Beacon Street on condition that granite repairs at the front stoop and garden curb use dutchman techniques - inset patches of matching stone - with samples approved by staff.³¹² An inset rectangle of slightly different stone in an old curb is often exactly that kind of repair.

Granite is the default, not an option. As of 2026, Public Works' right-of-way specifications cover granite curb 6 in (15 cm) wide in 24 in (61 cm) and 12 in (30 cm) depths, straight and curved, conforming to MassDOT's granite curbing specification, with a typical 6 in reveal along the roadway that may vary from 4 to 6 in with Public Works approval.³¹³ The standard details also include resetting existing granite curb, so old stones are often reused rather than replaced.²⁸⁷

What is the black and white T sign?

What you see: A white circle with a black ring around a bold black "T," on a pole or over a station entrance, sometimes with a red, orange, blue, green or silver band.

This is the MBTA's logo, "a black circle enclosing a truncated and capitalized Helvetica 'T'." It was already in the MBTA's first annual report in 1965 and was codified in the 1966 Manual of Guidelines and Standards.³¹⁴ The designers, Cambridge Seven Associates, studied European single-letter transit marks and found no US system using a "T."³¹⁵

The line colors were assigned August 26, 1965. Buses are yellow on maps, and Commuter Rail purple came in 1974.³¹⁶ Cambridge Seven chose the colors "for aesthetic reasons," and yellow was dropped for orange because white lettering did not show up on it. The popular stories tying red to Harvard crimson, blue to the harbor and green to the Emerald Necklace are, per GBH, "not entirely true."³¹⁷

What are the rows of blue bikes on the curb?

What you see: A line of blue bicycles locked into docks along a curb or sidewalk, with a kiosk at one end.

This is a Bluebikes station, metro Boston's public bike share. It launched in summer 2011 as Hubway with 60 stations and 600 bikes.³¹⁸ Boston, Brookline, Cambridge, Everett and Somerville manage it jointly, Lyft operates it, and Blue Cross Blue Shield of MA is the title sponsor.³¹⁸³⁰⁶

Counts depend on the date of the source. A February 2025 city presentation listed 530+ stations and 4,700 bikes systemwide, including 290 stations and 3,000 bikes in Boston (about 750 of them e-bikes), 4.7 million systemwide trips in 2024 (2.6 million in Boston) and a plan for 100 new Boston stations by summer 2025.³⁰⁶ As of October 2026, the city's Bluebikes page gives nearly 600 stations and 5,600 bikes across 13 municipalities, with Boston owning more than 345 stations and about 3,200 bikes.³¹⁸

Because the stations are municipally owned, a dock in the parking lane is city property on city curb, not a private business that set up shop. Where docks should go is a regular subject of neighborhood debate; the city's expansion meetings are where that happens.

What is the red line on the sidewalk?

What you see: A red line, painted in some places and set in red brick in others, running along sidewalks and across crosswalks downtown and in Charlestown.

This is the guide line for the Freedom Trail, a 2.5-mile (4 km) walking route linking 16 historic sites from Boston Common to Charlestown.³¹⁹ The idea came from Bill Schofield's March 8, 1951 column in the Herald-Traveler.³¹⁹ Mayor John B. Hynes dedicated the trail on June 11, 1951, with painted signs at 30 street corners and "no red line on the ground." The red line arrived in 1958, and the trail was extended into Charlestown in 1972.³²⁰ "It was Berenson's idea... to add the distinctive painted red line in 1958," according to the Freedom Trail Foundation's history of Dick Berenson.³²¹

Today much of the line is red brick.³¹⁹ It is a wayfinding line, not a utility locate mark.

Where the line runs over brick sidewalk, it is set in red brick; on concrete and crosswalks it was paint, which the city had to redo every year. In 2014 Public Works spent $50,000 replacing nearly 2,000 ft (610 m) of painted line with heat-applied thermoplastic strips, 10 in (25 cm) wide and patterned to look like brick, expected to last about eight years.³²²³²³

How do I report a broken streetlight or pothole in Boston?

What you see: A dark streetlight, a pothole, a knocked-down sign - and the "BOS:311" app or 311.boston.gov.

BOS:311 is Boston's non-emergency service request system. For a streetlight, use the 311 form "Report a lighting issue," or contact PWD directly at 617-635-5810 or publicworks@boston.gov.³⁰² Each report becomes a public web page showing its category, the department it went to (for example, Public Works, Street Lights) and its status.³¹¹

It gets used. Boston logged 287,148 requests in 2024 as of December 10, about 835 a day. Parking was the top category with 60,423, followed by street cleaning with 21,873.³²⁴

The most useful thing to include in a report is a precise location: an address, a nearby fire alarm box number, or a number from the pole itself. Anything involving fire, smoke, a gas smell or downed wires is a 911 call, not a 311 one. For how 311 systems route work, see the sister guide's 311 section.

What does "snow emergency artery" mean?

What you see: A parking sign on a main road referring to snow emergencies and towing.

When the city declares a snow emergency, parking is banned on posted snow emergency arteries, and cars left there are ticketed and towed so plows can keep main roads open. The city lists restricted streets in 20 neighborhoods plus 11 state roads. Discounted garages open from 2 hours before to 2 hours after the emergency, most at $10-15 per 24 hours. The city's own advice: "Always check the signs posted on the street."³²⁵ The Boston Transportation Department's sign guide (revised April 2016) shows the snow emergency sign reading "TOW ZONE DURING SNOW EMERGENCY" and lists it with the street cleaning signs, all 18 x 18 in (46 x 46 cm).²²⁹

What is the blue-and-white "Evacuation Route" sign?

What you see: A white square sign with a blue circle reading "EVACUATION ROUTE," sometimes with an arrow.

This is the federal EM-1 sign.³²⁶ In 2006, NPR reported that "New signs posted on every major thoroughfare in downtown Boston point to evacuation routes."³²⁷ Massachusetts also maps hurricane evacuation zones; Boston and Cambridge use a third zone, C, beyond the statewide A and B.³²⁸ The sign family and tsunami versions are covered in the work zones section.

Why is there a lawn chair in that parking space?

What you see: A lawn chair, traffic cone or trash barrel standing in a shoveled-out parking space after a snowstorm.

That is a space saver. As reported by CBS Boston in 2023, the city allows them only after a snow emergency is declared; they "can remain on the street for 48 hours after the snow emergency ends," after which Public Works may remove them, and they are banned in the South End.³²⁹ Some residents defend them as fair reward for shoveling; others see them as claiming public curb. Rules change, so check boston.gov before relying on any of this.

In Boston: a quick checklist

• Red box, white handle, red lamp overhead: Fire Department street box. Working equipment.
• Flickering lantern lit at noon: gas lamp, run by PWD.
• Brick sidewalk with a concrete middle strip: historic-district rebuild that keeps a 4 ft accessible path.
• Inset patch in a granite curb: likely a dutchman repair.
• Red line underfoot downtown: the Freedom Trail, not a utility mark.
• Something broken: BOS:311. Something burning: 911 or the fire box.

Elsewhere in the world

The Boston pattern travels. Most big cities split the street among a public works department, a transportation agency, utilities and a transit operator, and the exact lines differ from place to place, so a manhole cover's stamped name is usually a better guide to its owner than its location. Docked bike share on the Bluebikes model exists in many cities, under local names and sponsors. The fire alarm telegraph is rarer: New York still had about 15,000 boxes as of April 2026, while Washington, Atlanta, Baltimore, Dallas, Los Angeles, Philadelphia, Pittsburgh and St. Louis have stopped using theirs.⁶⁹ The US Evacuation Route sign is a federal design, so the same blue circle appears on coastal roads well beyond Massachusetts.³²⁶

Gas street lighting survives elsewhere too, and the same argument plays out. In London, Westminster City Council had about 300 gas lamps among 14,000 streetlights in 2022. After heritage groups objected to converting them all, the council agreed in November 2022 to keep 174 (138 of them listed) and convert 94 unlisted lamps to LEDs designed to imitate the gas glow, citing maintenance costs and its 2030 zero-carbon target.³³⁰

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17Cones, cabinets, stencils and temporary signs

The short version: Orange means a temporary work zone, and the cones, drums and barricades in it are built to national sizes and stripe patterns so drivers read them the same way everywhere in the US. Cardboard No Parking signs and street sweeping signs are the curb's temporary and recurring rules, and in Boston both end in tickets and tows. Green and gray boxes on the sidewalk are usually electric, telecom or traffic equipment, and you can often tell which by size, vents and stickers - but treat every one as live. Numbers on poles and boxes are asset IDs, bronze disks are survey marks, and blue-and-white signs with a circle or a wave mark evacuation routes.

What do orange cones, drums and barricades mean?

What you see: Orange cones, orange-and-white striped barrels, striped barricades on legs and boards closing a lane.

These are channelizing devices, temporary traffic control regulated in the US by Part 6 of the federal Manual on Uniform Traffic Control Devices (MUTCD). The specifications below come from Seattle DOT's Traffic Control Manual, a plain-language digest of the MUTCD that does not name its edition; the 11th edition (2023) was not checked for this guide.³³¹

Barricade stripes alternate orange and white and slope down at 45 degrees toward the side traffic should pass.³³¹ That makes the stripes a set of arrows: follow the direction the stripes slope downward, and you are going the way the crew intended.

A cone on a sidewalk around an open cover or a fresh patch belongs to whoever is working there. Moving devices around a work zone changes what drivers and pedestrians see, so leave them where they are, even after the crew has gone for the day.

What is the flashing arrow sign on a trailer?

What you see: A trailer- or truck-mounted panel of lights flashing an arrow or a moving chevron, parked ahead of a closed lane.

That is an arrow board. Under the Seattle manual, arrow boards are required where speeds are 40 mph (64 km/h) or more, and they supplement signs and channelizing devices rather than replacing them.³³¹ An arrow pointing right is telling you to merge right.

What do the STOP and SLOW paddles mean?

What you see: A worker in a high-visibility vest holding a sign on a pole that reads STOP on one side and SLOW on the other.

That worker is a flagger. The STOP face is red with white letters and the SLOW face is orange with black letters, and the paddle is at least 18 in (46 cm) wide. Flaggers wear ANSI/ISEA 107 Class 2 high-visibility garments by day and Class 3 at night.³³¹ SLOW means proceed with caution through the zone, not stop.

Why are work zone signs orange?

What you see: Diamond-shaped orange signs with black lettering: ROAD WORK AHEAD, LANE CLOSED, FLAGGER AHEAD.

In the US, orange is the work zone color. These signs belong to the same MUTCD Part 6 family as the devices above, and their job is to warn drivers well before the cones begin.

The rule is written into the manual. The 2009 MUTCD, Section 6F.16, says: "TTC warning signs shall be diamond-shaped with a black legend and border on an orange background," with the W10-1 railroad crossing advance warning sign as the exception, which stays black on yellow.³³² The 11th edition, issued in 2023, carries the same sentence in Section 6H.01.³³³

Who put up the cardboard "No Parking" sign?

What you see: Cardboard or paper signs fixed to poles reading "No Parking" with dates and times, for a move, a film shoot or construction.

In Boston, these are official City of Boston signs posted under a street occupancy permit. A 2014 city page for college students said moving permits require "cardboard City of Boston No Parking signs" at $4.00 each, that in residential areas they must go up at least 48 hours before the occupancy, and that the permit had to be obtained in person at City Hall at least 3 business days ahead.³³⁴

As of 2026 the process is largely online. For a moving truck, residents can buy a permit online at least 15 days ahead or in person at the Office of the Parking Clerk at City Hall at least three days ahead; a one-day permit for two non-metered spaces costs $69 including two signs, and signs must be up at least 48 hours before the 7 a.m. start.³³⁵ Construction and other street occupancy permits go through Public Works' online portal at least seven business days ahead, with a $50 base fee plus space charges, and signs cost $4 each.³³⁶

The 48-hour lead time gives drivers who parked before the signs went up a chance to see them and move. Boston also sends temporary no-parking alerts for events, moving and construction through notify.boston.gov/street-alerts.³⁰⁵

A homemade sign with no city marking is not the same thing. If you are unsure, the city sign will name the permit or the department.

How do I read a street sweeping sign?

What you see: A parking sign listing days, hours and months, such as "Street Cleaning, 1st & 3rd Tuesday, 8AM-12PM, April-Nov, Tow Zone."

It is a posted sweeping schedule. Cars left during the window are ticketed and towed so the sweeper can reach the curb. In Boston:³⁰⁵

• Daytime sweeping runs April 1 to November 30 in most neighborhoods.
• In the North End, South End and Beacon Hill it runs until December 31 and restarts March 1.
• Night sweeping runs year-round on main and arterial roads.
• If a sign shows no months, the rule applies year-round.
• In a month with a fifth week, weekly streets are swept and every-other-week streets are not enforced.

BTD issues the tickets and private companies it hires do the towing, at $132 plus $35 a day in storage plus a fuel surcharge. The city offers sweeping reminders at notify.boston.gov.³⁰⁵ Street cleaning was Boston's second-largest 311 category in 2024, with 21,873 requests.³²⁴

How do I tell utility cabinets apart?

What you see: Green, gray or beige metal boxes on sidewalks and lawns: short posts, waist-high boxes on concrete pads, tall gray cabinets at intersections.

These can be electric pad-mounted transformers and switchgear, telecom pedestals for phone, cable and fiber, or traffic signal and streetlight control cabinets. Color is a poor guide. Shape and hardware are better.

One explainer puts it plainly: "Size and shape are the most reliable indicators."³³⁷ Manitoba Hydro's advice is the part to remember: treat damaged equipment as live and keep at least 10 ft (3 m) away.³³⁸ Do not open, climb or sit on one, and do not dig near one without having the buried lines located first. In the US, that means contacting 811 before digging,¹ or Dig Safe in New England;¹² the paint section explains the marks locators leave.

In Boston, PWD alone runs about 1,600 streetlight control boxes,³⁰² so a modest gray cabinet near a row of lights may belong to the city, not a utility. For the electric system behind the green boxes, see the sister guide's power section.

A traffic signal cabinet houses the signal controller along with vehicle detection, power and communications equipment. US cabinets, covered further in the signal gear section, generally follow either the NEMA TS1/TS2 standards or the Caltrans-style 33X design built around a 19-inch equipment rack.³³⁹

What do the numbers stenciled on poles and boxes mean?

What you see: Stenciled or embossed numbers, small metal tags or stickers on light poles, utility poles, cabinets and boxes.

Most are asset IDs: the owner's way of naming one particular pole, box or cabinet out of thousands. Electric utility equipment typically carries a serial or equipment number alongside its red DANGER sticker.³³⁸ Boston's fire alarm boxes each carry "a designated number that identifies its location," and that number is what dispatchers see when the box is pulled.⁶⁹

Some codes record work rather than equipment. In New York, the blue "poker chip" disks and yellow "E" marks on streets are Con Edison paving markers showing the year of the work, so "E7" means 2007.³⁴⁰

The practical use is reporting. If a pole is leaning or a cabinet door is hanging open, quoting the number on it lets the owner find that exact item. Formats vary by owner and city, and there is no single national standard to decode them.

Newton, next to Boston, documents one local format. Its utility pole data, which came from the electric company, uses a pole ID that matches the number on the pole: a pole number followed by one or two post numbers separated by slashes, such as 123/5 or 112/4/5. Concrete poles on major streets were later given IDs made from a street abbreviation and the nearest address, such as WALN/1172 for a pole near 1172 Walnut Street.³⁴¹ Massachusetts towns often ask for that number when you report a streetlight out; Acushnet's form makes it mandatory.³⁴²

What is the round metal disk that says "do not disturb"?

What you see: A round bronze disk set in a sidewalk, curb, bridge or wall, stamped with an agency name and a warning not to disturb it. In the UK, an arrow with a horizontal bar cut into a wall.

This is a survey mark, a fixed point whose position or elevation has been measured precisely. Strictly, a benchmark is a mark of elevation. US disks are "bronze discs about 3.5 inches in diameter" (about 9 cm), and about 740,000 US benchmarks are in the National Geodetic Survey (NGS) database, each with a six-character permanent identifier, or PID.³² With the PID, anyone can look up the mark's datasheet.

UK benchmarks are usually carved into walls or set on metal plates, often on pubs and churches.³² Hunting them was a hobby hosted by Geocaching.com until 2023.³²

Surveyors still rely on these marks, so photograph them, look them up, and leave them alone. The survey marks section covers them in detail.

What do evacuation and tsunami signs look like?

What you see: A white square sign with a blue circle reading "EVACUATION ROUTE," sometimes with an arrow; on Pacific coasts, the same style with a breaking-wave symbol, or hexagonal signs announcing a tsunami hazard zone.

In the US, the EM-1 Evacuation Route sign is a blue circle on a white square with a white "EVACUATION ROUTE" legend and an optional white arrow, and it is retroreflective (MUTCD 2009, Section 2N.03).³²⁶ The tsunami version, EM-1a, keeps the white square and blue circle, adds a tsunami symbol, and requires a blue auxiliary arrow sign below it.³²⁶ Shelter signs in the EM-7 series (EMERGENCY, HURRICANE, FALLOUT, CHEMICAL) are black on white.³²⁶

Washington's methodology calls blue and white "generally accepted" for tsunami signs, and notes Oregon's "blue line project," which paints evacuation lines on roads.³⁴³ A blue line on a coastal Oregon road is therefore more likely an evacuation line than a water utility mark.

In Boston: NPR reported in 2006 that "New signs posted on every major thoroughfare in downtown Boston point to evacuation routes."³²⁷ The threat there is hurricane storm surge. Massachusetts maps hurricane evacuation zones A and B, which flood first; Boston and Cambridge also use a Zone C. Zones do not equal hurricane categories, and the state's advice is "Know Your Zone."³²⁸

Japan has its own system. In March 2016 it published JIS Z 9098, a set of evacuation guidance signs organized by disaster type that includes tsunami evacuation area and tsunami evacuation building signs, drawing on symbols from ISO 20712-1, the international water safety sign standard; Japan then proposed the system to the ISO committee for graphical symbols, ISO/TC 145/SC 2.³⁴⁴

Chile's national reference guide for municipal tsunami evacuation systems (Ministry of Housing and Urbanism with Onemi and other agencies, October 2017) calls for painting existing utility poles red with symbols showing the evacuation direction, painting meeting points and the first block of the safe zone green, and using photoluminescent signs that show the direction, the nearest meeting point and the distance in blocks to the safe zone.³⁴⁵

In Boston

• Cardboard City of Boston No Parking signs come with a street occupancy permit and, per the 2014 rules, must be posted 48 hours ahead in residential areas.³³⁴
• Sweeping season is April through November in most neighborhoods, longer in the North End, South End and Beacon Hill, and year-round at night on arterials.³⁰⁵
• Gray cabinets near streetlights may be among PWD's 1,600 control boxes.³⁰²
• Downtown thoroughfares carry EM-1 evacuation signs for storm surge.³²⁷

Elsewhere in the world

The device sizes and colors in this section are US rules. Other countries set their own temporary traffic control standards, and the details differ. Survey marks are a clear case of local style: bronze disks in the US, cut arrow marks and wall plates in the UK.³² Tsunami sign colors converge on blue and white across many jurisdictions,³⁴³ though Washington uses an orange hexagon for entering a hazard zone. For how roads are built and dug up in the first place, see the sister guide's roads section.

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18Test yourself

The short version: Fifteen questions drawn from this guide, from easy to surprising. Each answer explains itself and links to the section that covers it.

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19The glossary

The short version: Every term of art in this guide in plain words, searchable and sorted by where you would see it. If a word on a sign, a cover or a locate ticket stopped you, it should be here.

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20Where to go next

The short version: The best places to keep going, none of them ours: the standards and manuals these marks come from, the agencies that publish the rules, and the people who photograph and catalog this stuff for fun.

21Open questions and known gaps

The short version: What we looked for and could not pin down well enough to print. If you can source any of it, the corrections desk below wants to hear from you.

22Corrections and updates

The short version: This guide will have mistakes in it, and the people who know best are the ones who run these systems every day. If something here is wrong, out of date or missing credit, tell us and we will fix it and log the change below with the date.