Meet the intelligent traffic signals

Ben Webster

THOUSANDS of deaths and injuries could be prevented each year by a new type of traffic light that detects when a vehicle is about to ignore a red signal and delays showing green to drivers on opposing roads.

The new technology will also reduce delays by calculating how much traffic is building up on each road and automatically adjusting the timings of the green phases accordingly.

Research commissioned by the Department for Transport has found that “co-operative lights”, which can respond to road conditions and driver behaviour, would reduce costs to the economy from crashes by £125 million a year.

Last year there were 3,980 injuries at traffic lights caused by drivers disobeying red signals. These included 25 deaths and 339 serious injuries.

The report by the Transport Research Laboratory concludes that the overall benefits of the technology could exceed £500 million when the savings on journey times are included.

It gives warning, however, that there would have to be strict controls to prevent drivers abusing the system. Cameras would have to be installed alongside the new lights to catch motorists who knew that other vehicles would have to wait if they jumped a red signal.

The report also proposes using the technology to shorten the time lapse between lights turning red in one direction and turning green in another. The lights would detect when all vehicles were braking sufficiently to stop in time and instantly would give a green light to opposing traffic.

Drivers could also be given advance notice of the number of seconds before the lights were going to change to red. Similarly, motorists waiting at red signals would know when they were going to turn green, allowing them to put vehicles in gear and prepare to start promptly.

The report says that even greater safety benefits would be possible by making the lights interact with the vehicle, automatically applying the brakes if the driver was in danger of overrunning a red signal. The department is already conducting trials in Leeds of a car that brakes automatically when the driver exceeds the speed limit.

The European Commission is developing proposals for a compulsory onboard unit to be fitted to all new cars. The report says that the unit would be capable of communicating with traffic lights as well as allowing vehicle speeds to be controlled remotely.

It acknowledges that many drivers would resist fiercely any proposal to override their control of vehicles and proposes that, as a first stage, drivers could be prevented from moving off at lights until they have turned green. The full system could be introduced later when there was broad public support.

The Parliamentary Advisory Council for Transport Safety said that the technology could result in safer and more predictable journeys. Rob Gifford, its director, said: “The system can tell drivers that if they stick to a certain speed below the limit, they will find a succession of lights changing in their favour.”

The number of sets of traffic lights in London has increased by a fifth, or almost 1,000, since Ken Livingstone, the Mayor of London, came to power in 2000. Responding to a question from the London Assembly Conservatives, Mr Livingstone said that the number of lights had increased by 982 to 5,827. He claims that many of the new lights are essential to allow pedestrians to cross in safety.