LED Traffic Lights Get the 'Green Light'

Our antiquated traffic lights are soon to receive a green makeover in the form of LED lighting.

There are around 420,000 traffic and pedestrian light signals in the UK, most of which are still using 50-watt incandescent bulbs. The power needed for this many lights works out to 100 million kWh of electricity every year and accounts for 57,000 tonnes of carbon dioxide emissions. At 17-watts each, LEDs have the potential to cut energy consumption and pollution by up to 60 per cent.

But the benefits don't stop there. LEDs are also brighter, last longer and, unexpectedly, could help colour-blind motorists.

LED traffic signals use hundreds of tiny LEDs wired in series and parallel to create an array. The light produced by an array is brighter and clearer than an incandescent bulb. This makes them easier to see at night and in bad weather, allowing motorists to react quickly and improving road safety.

Replacing traffic signals is a long and costly process. Incandescent bulbs need changing every 12 - 18 months. LED lights last for about 5 years, resulting in less cost and frustration.

LEDs also eliminate the risk of 'blow-outs.' An incandescent bulb has a single point of failure, its filament. Once this burns out, the bulb needs replacing. LED arrays are made up of hundreds of individual LEDs. Even if several fail, the rest will continue to work.

Because they need very little power, LEDs could also make solar powered traffic lights feasible. Now that's really 'green.'

LEDs could also help colour-blind drivers. A Japanese scientist, professor Taro Ochiai, has developed traffic lights which look normal to regular motorists, but, thanks to a discrete configuration of LEDs, help motorists with colour-blindness to differentiate between 'stop' and 'go.'

Anyone still unconvinced may find the following case studies of interest:

Back in 2009, Transport for London (TfL) began work on replacing 3,500 traffic signals within the capital, with projected savings of A�200,000 a year. By replacing all of its traffic lights, London could eliminate 12,000 tonnes of CO2 emissions.

Brazil completed its own award-winning traffic light scheme in 2008. By using LEDs, the city of Guarulhos has cut its yearly energy bill by A�150,000 and saves enough electricity for 558 homes.

So, the next time you are waiting at an intersection, it may be LEDs providing the familiar red, amber and green glow.