How do speed camera vans work?

In the United Kingdom, so-called speed camera vans feature four cameras mounted on the front, back and sides which can capture a speeding motorist at a distance of a half a mile. The front camera captures the license plate as the vehicle drives away while the side cameras capture vehicles passing by and a police officer uses a laser gun to determine the speed.

Older speed capture vans featured only a single camera and often did not capture the license plate of the car in question. The four-camera version can capture a vehicle that approaches from either direction, taking pictures from the front, sides and back as it passes by.