97 Fun Facts About Traffic

The world's first traffic signal, a gas-lit semaphore of 1868, stood outside which London landmark?

The Houses of Parliament: railway man John Peake Knight adapted a train signal so that MPs and other pedestrians could cross the road, and a police constable worked its arms and lamp by hand.

What fate befell the world's first gas-lit traffic signal only weeks after it was switched on in 1868?

It exploded: a gas leak blew the signal up on 2 January 1869, injuring the police constable who was working it, and the experiment was taken down.

In which city did the American Traffic Signal Company install an electric traffic light at Euclid Avenue in August 1914?

Cleveland: the signal at Euclid Avenue and East 105th Street sounded a buzzer before each change, and police and fire stations could take control of it to clear a path in an emergency.

Which inventor patented a manually operated three-way traffic signal with moving arms in 1923?

Garrett Morgan, already known for his smoke hood, designed the signal after seeing a horse-drawn carriage and a car collide at an intersection.

Which country decreed in 1973 that the 'go' light should be the bluest possible shade of green?

Japan: the Japanese word for the go light, ao, traditionally covered both blue and green, so a 1973 order specified the bluest permissible shade of green to match the name.

In which US city did the first stop sign go up?

Detroit: in the 1920s highway officials ranked sign shapes by danger and gave stops the octagon, so that drivers could tell what a sign meant even when they couldn't read it.

Until a 1954 rule change made them red, US stop signs had spent thirty years as which colour?

Yellow: red signs of the 1920s were too hard to see at night, so the 1924 standard put stop signs on yellow, and red took over only when fade-resistant reflective finishes arrived.

Traffic pioneer William Phelps Eno untangled which crash-prone Manhattan junction in 1905 by making it one-way?

Columbus Circle: carriages and cars had gone round it both ways, crashing almost daily, until Eno sent them one way; the author of New York's first traffic code never learned to drive.

The United Kingdom adopted which roundabout rule nationwide in 1966?

Entering traffic gives way to circulating traffic: the rule is what separates a modern roundabout from its forerunners, which jammed at busy times and needed police to keep them moving.

The Magic Roundabout of 1972, five mini-roundabouts ringing a central island, is in which English town?

Swindon: drivers go round the central island anticlockwise, against the normal British flow, and the junction took its name from a children's television show.

Which Midwestern suburb bills itself as America's roundabout capital, with more than 150 built since the late 1990s?

Carmel has spent decades replacing its traffic signals with roundabouts, one junction after another, and now has more of them than any other city in the United States.

Britain's Locomotives Act of 1865 made someone walk ahead of each road locomotive carrying what?

A red flag: the 'Red Flag Act' also held road locomotives to 4 mph at most, and though the flag was dropped in 1878, someone still had to walk in front until 1896.

Jacob German, arrested in Manhattan in May 1899 for doing 12 mph on Lexington Avenue, worked as what?

Cabbie: German drove one of the Electric Vehicle Company's battery-powered taxis, so the car in what is usually called America's first speeding arrest was electric.

The Emancipation Run of November 1896, celebrating a new 14 mph speed limit, took pioneer motorists from London to which seaside town?

Brighton: the drive celebrated the Act that lifted the limit from walking pace, and it lives on as the London to Brighton Veteran Car Run, a yearly outing for the very oldest cars.

Which country moved all its road traffic from the left side to the right at 5 a.m. on 3 September 1967?

Sweden: Dagen H went ahead even though 83% of voters had rejected the change in a 1955 referendum; lawmakers overruled them because every neighbouring country already drove on the right.

Which island nation followed Dagen H by switching to driving on the right in May 1968?

Iceland changed over on 26 May 1968, a day it called H-dagurinn; it had kept left even under Danish rule, and wartime British occupation had delayed an earlier plan to switch.

Which Pacific nation switched from right-hand to left-hand traffic in 2009?

Samoa: on 7 September 2009 it became the first country since the 1970s to change sides, moving to the left so that islanders could import cheaper used cars from Australia and New Zealand.

Which country opened what is often called the world's first motorway in 1924?

Italy: Piero Puricelli's Autostrada dei Laghi linked Milan with Varese as a toll road for motor vehicles only, though this first motorway had just one lane in each direction.

Which US president, who had crossed the country in a slow 1919 army truck convoy, signed the act creating the Interstate system?

Dwight D. Eisenhower signed it in 1956: the 1919 convoy had needed 62 days to cross the country, and Germany's autobahns later showed him what fast roads could do for defence.

Route 66 began in Chicago and, after a 1930s extension, ended in which California city?

Santa Monica: the highway first stopped in downtown Los Angeles before being pushed on towards the ocean; bypassed by the Interstates, it was removed from the US highway system in 1985.

Britain's first motorway, the Preston By-pass, opened in December 1958 and shut within weeks after what damaged its surface?

Frost: water in the road froze and thawed, breaking up the surface, so the motorway that Harold Macmillan had opened on 5 December was closed again for repairs in January 1959.

The world's first parking meter, championed by lawyer and publisher Carl Magee, went into service in July 1935 in which city?

Oklahoma City: downtown workers were taking every kerb space all day, so the meters charged a nickel an hour to keep the spaces turning over for shoppers.

The 100 km traffic jam of August 2010, lasting more than a week, clogged a coal-truck route into which Chinese city?

Beijing: coal lorries from Inner Mongolia had worn the road out, and the repair works meant to fix that damage cut its capacity and set off the jam.

'Carmageddon' was the nickname for a July 2011 weekend closure of which Los Angeles freeway?

I-405: the 15-17 July 2011 closure through the Sepulveda Pass let crews demolish part of the Mulholland Drive bridge; traffic was lighter than feared and cyclists beat a JetBlue flight across town.

The word 'gridlock' spread from a New York City traffic engineer's memo during which 1980 event?

A transit strike: during New York's April 1980 transit strike, engineer Sam Schwartz's memo titled 'Gridlock Prevention Plan' was picked up by newspapers and the word spread nationwide.

Yorkshireman Percy Shaw made his name by patenting which night-driving aid in 1934?

Cat's eye road studs: each reflector sits in a rubber dome that a passing tyre presses down, wiping the glass clean, and the wartime blackout proved their worth on unlit roads.

The world's first zebra crossing was installed in 1951 in which English town?

Slough: the first zebra crossing opened on Slough High Street on 31 October 1951; the name is credited to James Callaghan, then a junior transport minister, who said the stripes looked like a zebra.

Belisha beacons are named after Leslie Hore-Belisha, who held which post in 1934?

Minister of Transport: with more than 7,000 people a year dying on Britain's roads, Hore-Belisha also brought in the driving test and a 30 mph limit in built-up areas.

Introduced in the UK in 1969, the pelican crossing takes its name from a compression of which phrase?

Pedestrian light controlled: officials shortened it to 'pelicon', then changed the last syllable to match the bird; it replaced the panda crossing, an experiment that had failed.

In the American slang that produced 'jaywalker', what kind of person was a 'jay'?

A country bumpkin: a 'jay' was a gullible rustic lost in city traffic, and in the 1920s the motor industry spread 'jaywalker' to shift the blame for road deaths onto pedestrians.

Which Australian state led the country in 1970 by making it compulsory to wear a seat belt?

Victoria: New South Wales copied its law the following year, and the rest of the country soon fell into line.

Nils Bohlin's modern three-point seat belt was introduced in 1959 by which carmaker?

Volvo: Bohlin had designed ejector seats for Saab's aircraft before joining Volvo in 1958, and Volvo then let every other carmaker use his belt design for free.

Charles Scanlon patented the traffic cone in 1943 to replace the wooden tripods he used in what job?

Street painter: Scanlon, of the Los Angeles street painting department, found the wooden barriers round fresh paint broke too easily, so he made a rubber cone that sprang back upright when a car clipped it.

The first edition of Britain's Highway Code, published on 14 April 1931, cost how much?

One penny: the 1931 booklet carried adverts, told drivers of horse-drawn vehicles to signal a turn by rotating the whip above their heads, and showed no road signs until its second edition.

The Pan-American Highway is broken by the Darién Gap, between Panama and which country?

Colombia: a road was planned with American money in the 1970s but halted over fears that it would destroy rainforest and let foot-and-mouth disease spread north.

The Yungas 'Death Road', called the world's most dangerous in 1995, is in which country?

Bolivia: the North Yungas Road from La Paz to Coroico earned the 1995 label, and unlike the rest of Bolivia drivers keep left there so they can see how close their wheels are to the edge.

Which city's 1975 Area Licensing Scheme was the world's first urban congestion pricing?

Singapore: drivers bought a paper licence to enter the centre, and officers at the entry points checked each passing windscreen by eye until electronic gantries took over in 1998.

Braess's paradox, that adding a road can slow traffic, is named after Dietrich Braess, a German what?

Mathematician: Dietrich Braess of Ruhr University Bochum described the paradox in 1968, and Seoul later saw it run in reverse, when traffic sped up after an elevated expressway was torn down.

Which company bought the Israeli-founded navigation app Waze for a reported $1.3 billion in June 2013?

Google said that Waze's developers would stay in Israel and go on working as a separate team, while their live traffic reports would be used to improve Google Maps.

A grooved stretch of Route 66 in Tijeras, New Mexico plays which song when driven over at exactly 45 mph?

America the Beautiful: the rumble strips laid on Route 66 east of Albuquerque in 2014 hum the tune at 45 mph; Lancaster, California has a similar road that plays part of the William Tell Overture.

The United States imposed a national 55 mph speed limit, not fully repealed until 1995, in response to what?

The 1973 oil crisis: Nixon signed the limit in January 1974 to save fuel, and because speed limits belonged to the states, Washington enforced it by threatening to withhold their highway money.

Which city's stretch of Highway 401 ranked as North America's busiest highway in 2019?

Toronto: the stretch, carrying over 400,000 vehicles a day by 2019, opened in the 1950s as the Toronto Bypass, laid out north of the built-up area so that through traffic could avoid the city.

The Katy Freeway, at 26 lanes believed to be the widest in the world since a 2008 expansion, serves which city?

Houston: Interstate 10's Katy Freeway west of downtown Houston reached 26 lanes after its 2008 widening, a count that includes frontage roads and managed toll lanes as well as the main carriageways.

On Germany's autobahns, the 130 km/h Richtgeschwindigkeit is what kind of speed?

A recommended maximum: going faster is legal where no limit is posted, but a driver above 130 km/h can be held partly liable for a crash even if someone else caused it.

Which term describes new traffic filling a widened road, an effect likened to curing obesity by loosening your belt?

Induced demand: studies of American cities found that driving rises in step with road space, so a network with 10% more lane-miles soon carries about 10% more traffic.

Policeman Lester Wire's 1912 electric traffic light, a wooden box in Salt Lake City, showed which colours?

Red and green: Wire is said to have dipped ordinary bulbs in paint, locals laughed at a box that looked like a birdhouse, and he never patented it; an amber lamp only arrived with a 1920 design.

In Quebec's horizontal traffic lights, what shape is the amber aspect?

A diamond marks amber, with a square for red and a circle for green, so that drivers who cannot tell the colours apart can still read the signal by its shape.

On the most common type of three-lamp traffic light, where is the red lamp placed?

At the top is the standard spot for red, with amber in the middle and green below; a signal mounted sideways keeps the same running order along a row.

In which Southern Hemisphere country do drivers call traffic lights 'robots', a word popularised by a 1920s play?

South Africa kept the name long after Britain dropped it: 'robot' was once British English for the new automatic signals too.

Which Netflix series begins its deadly contest with a giant doll overseeing Red Light, Green Light?

Squid Game named its first episode after the playground game, which was picked because it could knock out a huge number of contestants in one go.

The first traffic signal, with its red and green lamps, copied the signalling of which older transport network?

Railways supplied both the idea and the builders: the 1868 design came from an engineer who made train signals, with moving arms by day and coloured gas lamps by night.

The sensor loops buried in the road at many traffic lights detect a waiting vehicle by sensing what?

Its metal body disturbs the loop's magnetic field, which is why a signal can fail to notice a bicycle or a small motorbike: weight plays no part.

Which energy-saving lamps in modern traffic lights run so cool that snow can settle on them and hide the signal?

LEDs use a fraction of the power of the old incandescent bulbs, which wasted enough heat to melt snow off their own lenses.

Thimphu, where police with dance-like gestures stand in for traffic lights, is the capital of which country?

Bhutan's capital once put up a set of traffic lights but soon took them down again, and went back to officers directing the cars by hand.

Keeping the lamps of a traffic light in a fixed order mainly helps drivers with which condition?

Colour blindness can make red, amber and green hard to tell apart, so affected drivers memorise where each lamp sits rather than what it shows.

Augsburg and Cologne set traffic lights into the pavement to catch the eye of pedestrians staring at what?

Smartphones keep so many walkers looking down that one Zagreb junction also aims its red light at the ground, where the glare shows up on their screens.

In the US, what does a flashing amber traffic light tell an approaching driver to do?

Proceed with caution is the rule: nobody has to halt, but cross traffic facing a flashing red may pull out once it has paused.

Tipperary Hill, where Irish-American locals won an upside-down traffic light, is a district of which US city?

Syracuse gave in after youths kept smashing the original signal, and the inverted light still hangs on Tipperary Hill as the only one of its kind in the country.

Which American police officer created the first four-way, three-colour traffic light in 1920?

William Potts ran the signals for his city's police department, and his light's third, amber lamp gave drivers warning that a change was coming.

Charles Adler Jr.'s 1928 Baltimore traffic signal turned green when a waiting driver did what?

Sounded the horn is right: the signal listened for a honk and then changed, a system built for quiet side roads that met busy main ones.

What name do engineers give a run of coordinated traffic signals that drivers at a set speed pass without stopping?

Green wave timing works for bikes too: Copenhagen sets the signals on one main street so that cyclists holding 20 km/h sail through every junction.

Which Pennsylvania city gives its name to the custom of letting a left-turning driver go before oncoming traffic?

Pittsburgh's hilly terrain and many two-lane roads made the courtesy popular, though it has no basis in law and counts as a traffic violation.

Germany's first traffic light tower, its lamps worked by a lone policeman, rose in 1924 on which Berlin square?

Potsdamer Platz was then called the busiest traffic centre in Europe; the lone officer in the tower's cabin was replaced by automatic switching in 1926.

The column of amber and green lights that counts drag racers down to the start is nicknamed what?

Christmas tree lights also catch a jumped start: leave before the green and the count stops dead while a red lamp lights in the offender's lane.

Pedestrian crossing buttons that no longer change the traffic lights are nicknamed after which medical term?

Placebo buttons look functional but do nothing when pressed, and many once-working walk buttons in big cities have quietly joined their ranks.

From 2013, solar-powered humanoid robots standing 2.5 metres tall began directing traffic in which African capital?

Kinshasa's robots came from engineer Thérèse Kirongozi, who wanted something incorruptible on roads where drivers could bribe their way out of trouble.

Preemption systems, triggered by a coded strobe or infrared beam, turn traffic lights green for what?

Emergency vehicles carry an emitter that pulses at a set frequency; the signal reads it and halts conflicting traffic, cutting response times.

In the US, a faulty traffic signal flashing red in every direction legally operates as which kind of junction?

An all-way stop is what the junction becomes: every driver must halt and then take turns, exactly as if a sign stood at each corner.

A US driver holding the left arm out of the window, forearm bent straight up, is signalling what?

A right turn has two accepted signals in the US: the bent left arm that drivers use, or the other arm held straight out, as many cyclists prefer.

The 1968 United Nations convention that standardised road signs and traffic signals is named after which European city?

Vienna hosted the month-long conference in 1968, and its treaty revised and greatly extended an earlier protocol agreed in Geneva in 1949.

Which US state names the rule, first passed there in 1982, letting cyclists treat a stop sign as a yield sign?

Idaho stood alone for 35 years: no other state copied the law until Delaware passed a limited version in 2017.

In northern European cities, patterns of white lights replace red, amber and green on the signals for which vehicles?

Trams read shapes instead of colours: an S for halt, a horizontal bar as a warning and an arrow for go, quite unlike the lamps shown to cars.

What name is given to the traffic lights that feed vehicles onto a busy freeway a few at a time?

Ramp meters often show only red and green, with no amber at all, and ration cars onto the freeway to break up the bunches that cause congestion.

Nobel physicist Arthur Compton designed which traffic-calming device in 1953 to slow cars near his university?

Speed bumps began as what Compton called 'traffic control bumps', drawn up after he saw how fast motorists passed Brookings Hall in St. Louis.

Which silent film actress, often called cinema's first star, is credited with designing an early car turn signal?

Florence Lawrence devised an 'auto signaling arm' and a mechanical brake signal but patented neither, so she never earned a cent from them.

Which British comedy troupe recorded a song in praise of traffic lights for a 1980 Contractual Obligation Album?

Monty Python's song was written by Terry Jones and shares the record with other oddities such as 'Decomposing Composers'.

SCATS, an adaptive traffic signal system used from Dublin to Shanghai, takes its initial S from which city?

Sydney is the S in the Sydney Coordinated Adaptive Traffic System, which runs about 11,000 junctions across Australia and is owned by New South Wales.

Which US state is known for the 'jughandle', a side loop that makes drivers exit right in order to turn left?

New Jersey already had 160 jughandles by 1960, enough for the move to be nicknamed the Jersey left, and in 2013 a bill to ban them reached the state senate.

Which US state names the junction design where drivers wanting to go left must first pass through and make a U-turn?

Michigan has built the layout along its divided highways since the late 1960s; traffic engineers know it by the plainer name median U-turn.

Ashville, whose museum shows a 1932 signal certified as the oldest working traffic light, is in which US state?

Ohio's little Ashville credits resident Teddy Boor with inventing the light, and Guinness World Records has backed its claim to be the oldest still functioning.

In which Canadian province does a flashing green traffic signal mean it changes only when a walker presses the button?

British Columbia stands apart: in Ontario and most other provinces a flashing green is an 'advanced green', a head start for turning drivers.

Which English town trialled Britain's first automatic traffic lights in 1927, at a junction on Princes Square?

Wolverhampton's experiment came 59 years after the very first gas-lit signal, which a constable had to work by turning a crank.

Hans Monderman pioneered which street design, which removes traffic signals and signs so that drivers seek eye contact?

Shared space works by making priority unclear: Monderman argued that uncertain drivers slow down, and he tried the idea first in the towns of Friesland.

What do Americans call a pedestrian scramble, the signal phase that halts every vehicle so walkers can cross diagonally?

Barnes Dance honours Henry Barnes, the traffic engineer who brought it to Denver in the 1940s after seeing how hard his daughter found the walk to school.

The HAWK beacon, a crossing signal that stays dark until a walker calls it, debuted in 2000 in which Arizona city?

Tucson's transportation chief built the prototype after admiring a British crossing on a trip to Bristol, and his wife suggested the bird-of-prey name.

The animated green man of pedestrian signals, who strides faster as time runs out, debuted in 1999 in which Asian city?

Taipei calls him Xiaolüren, the Little Green Man, and paired him with a countdown display; within a few years he had replaced static signals across Taiwan.

Which bird names the British signal crossing shared by pedestrians and cyclists, a pun on its two kinds of user?

Toucan plays on 'two can' cross together, and the newer ones light a green bicycle beside the green man when both groups may go.

Which Beatles album cover made a zebra crossing so famous that the crossing was given Grade II listed status in 2010?

Abbey Road shows the four walking over the stripes outside their studio, in a photograph taken on 8 August 1969 from an idea McCartney had sketched.

British school crossing patrols are nicknamed after which sweet?

Lollipop men and women take the name from their circular sign on a stick, and 'lollipopping' has even become a verb for the job.

Which Tokyo scramble crossing, often called the world's busiest, sees up to 3,000 people cross on a single green light?

Shibuya stays crowded round the clock, and one survey counted some 260,000 people crossing on a weekday, rising to 390,000 on days off.

East Berlin's Ampelmännchen, the little pedestrian signal man created in 1961, is known for wearing what?

A hat that risked being judged petit bourgeois survived the design review, to its creator's surprise.

Which car pioneer was issued an 1888 driving permit after neighbours complained about his noisy, smelly Motorwagen?

Carl Benz needed written permission from the Grand Ducal authorities to keep using public roads, a paper often counted as the first driving licence.

On US pedestrian signals, which symbol replaced the old lettered warning to tell walkers not to start crossing?

An upraised hand in Portland Orange took over from the words, partnered by a white walking person for the go signal.

Which mythical creature names the British signal crossing built for horse riders, with a push button two metres up?

Pegasus crossings let riders press the high button without dismounting, and the signals swap the usual green and red men for little horses.

Britain's Automobile Association was founded in 1905 chiefly to help motorists avoid what?

Speed traps were flagged by AA patrolmen until a court ruled that illegal; after that, a patrolman who failed to salute a member meant police ahead.

Maurice Gatsonides, who invented the Gatso speed camera to time his own cornering, made his name in which motorsport?

Rallying brought him victory in the 1953 Monte Carlo Rally in a Ford Zephyr; the camera he built to go faster now catches drivers who do.

Seiichi Miyake invented which street surface in 1965, now found at crossings and station platforms worldwide?

Tactile paving took its cue from braille: blocks of round studs warn of a hazard ahead, while long, slender ridges show the direction to walk.