Traffic Light things!

[Dexton]

What are those camera looking things ontop of some traffic lights? Some people say they are used by the emergency services to change the lights when they approach. But some of them seem to be pointing down at the pavements. So what are they called and how do they work, please.

[sddsddean]

They are microwave detectors used to detect the approach of traffic and pedestrians waiting to cross, so that the computer in the control box can set the relevant light to green at times of low traffic flow, rather than having to go through the whole cycle. They also detect high traffic rates, so that the computer can extend the green phase to try and avoid too long a queue at the lights.

[emma_26]

thank god thats what they are cos i ran a red light at a crossing the other week and worried id get a fine through the post!

[emma_26]

oh and no nobody was crosing at the time lol

[Jay70]

They could be cameras - we have them here in Slough to detect red light jumpers.

[ugly_bob]

red light cameras don't have to be yellow - only speed cameras.
Cameras for lights/bus lanes/parking offences are usually housed in small grey boxes

[emma_26]

so i might be in trouble then? great!

[peanut]

Did you at least smile on your way by ?

[ugly_bob]

emma - you'll probably be OK. Most of them are just sensors like sddsddean says. The cameras tend to be mounted on separate poles, rather than directly on top of the lights.