speed traps

[v banks]

how do speed trap cameras work?

[andy hughes]

The speed trap camera works on a simple principle. A sensor beam directed at the traffic is pre-set to recognise a speed limit. If a vehicle breaks the beam travelling above the limit, the camera takes two photographs, one half-a-second after the other. When developed, the operator can check the wheel spacing on the white lines in the road, and from the number of lines passed in the half-second, they can calculate the spped the vehicle was travelling. That's why speed cameras are accompanied by broken horizontal lines in the road, and why some people appear to have black marks over their rear number plates. It may disguise your number in a trap, but you break the law by obscuring any part of your number plate, and can be fined for that offence. Some police forces allow cameras to flash, without film in the camera - no-one knows which are filming, and which not, but it works as a deterrent against speeding, which is the idea in the first place.

[pleaser]

Basically it is a camera that takes picture(s) of your car along two set points on a given road. For example across 100 metre points, say this took 6 seconds to cover this distance(keep it simple) it then multiply's 100mtres by 10 to equal 1km, muliply's time by 10 also, which equals 60 sec's or 1 min to cover 1km which then gives a speed of 60 kilometres per hour if 1 km is covered in one minute, Hand

[foxinsocks]

The camera makes several hundred calculations as your vehicle enters the (typically) 20 metre catchment zone. It then compares the first 120 calculations with the second 120 and then if the difference fits the pre-set parameters, SNAP! Although, it is worth noting, that all operational speed cameras flash if you are going two fast. One flash means that there is no film in the camera, two flashes means expect a nice letter.