The majority of safety camera vans are using laser-based systems to measure a vehicle's speed. These will normally have some sort of video equipment attached to record the evidence.

How do they work?
Mobile laser systems are often found in vans, which can target vehicles from short or long range. The laser is aimed at the number plate and the returned signal bounces back to the gun to determine the speed. Evidence of which number plate was targeted is recorded on the video, or may be noted by the operator.

Accuracy
Laser is a very accurate system, with a speed acquisition time as little as 0.3 seconds. T his is the reason laser guns are being used rather than the old-fashioned radar guns, which found it hard to determine which car was the target. There are various types of laser equipment in use, but all currently use the same 904nM light beam.

How do they help road safety?
Mobile camera sites can be set up as and when required, so they have the flexibility to be used in many locations on the same day. They are a deterrent to speeders, although the van should be parked in a safe position so as not to cause any obstruction to other road users.

They ( Susan Beck, National Spokesperson Safety Camera Partnerships ) Say:
A study into the effectiveness of safety cameras was carried out by University College London in February 2003. This report was subsequently published by the DfT and it proved a 35% reduction in the number of people killed and seriously injured on the roads at camera locations and a 56% reduction in the number of pedestrian casualties at the same sites. There was a 10% reduction in average speeds in the areas monitored and there was over 80% support from the public for the use of safety cameras at locations historically blighted by speed related crashes.”

We Say:
There are an increasing number of safety camera vans on Britain's roads. Because of the speed and accuracy of laser, getting advance warnings will depend on each particular situation.