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Posted by on Jul 13, 2016 in Tell Me Why |

When Were Traffic Signals Installed?

When Were Traffic Signals Installed?

The world’s first traffic signals or lights were installed near London’s House of Commons in 1868. Non-electric and gas-operated, police officers had to work the lights by hand in a bid to control vehicles crossing on nearby Bridge Street, Great George Street and Parliament Street.

The project was short-lived after an explosion in 1869 when a leak in gas lines passing under the device exploded, and seriously injured the police officer operating the lights.

More than thirty years later an American enjoyed greater success with some electronic lights that focused on a similar – and now internationally recognizable – system of red and green lights.

Lester Wire, a former detective in Salt Lake City, came up with the revolutionary idea in 1912, and traffic lights began springing up across the United States shortly after.

He was not the only American to come up with the idea. Garrett Morgan, an inventor from Ohio, vowed to improve traffic safety after witnessing a serious accident on the roads.

He applied for a patent for a man-powered traffic control device using a crank in 1922, but his invention is said to have never reached the prototype stage.

It has been speculated that local authorities were reluctant to invest in a man-powered set of traffic signals because it would require cities to hire someone to staff it all day – whereas the emergent electric lights seemed far cheaper in comparison.

In 1920 bells were added to traffic light systems to alert motorists when the lights were about to change – they were later replaced with the amber light now seen on all traffic light systems today.

It wasn’t until 1990 that countdown timers were introduced, allowing pedestrians to judge whether there is enough time for them to cross the road before the lights turn red.

Perhaps the most impressive traffic light specimen ever to be unleashed on the world’s streets was the Traffic Light Tree, created by French sculptor Pierre Vivant in 1998. The imposing eight-metre tall tree consists of 75 sets of lights and has become a favorite spot for tourists in London.

These days, traffic lights are highly sophisticated, incorporating special light symbols for bikes, trams and buses. Some also feature signals that are interruptible, giving priority to emergency vehicles via transmitters that send radio waves, infrared signals, or strobe light signals that are received by a sensor on or near the traffic lights.

While most countries have become dependent on traffic lights over the decades, some places are happy to do without them. In Ethiopia’s capital Addis Ababa, a huge intersection runs smoothly without a single traffic light.

Content for this question contributed by Ken Ryan, resident of Santa Cruz, Santa Cruz County, California, USA