Speed camera flash light. This GATSO speed camera has been triggered by a speeding vehicle and is taking a picture (as shown by the flash) of the vehicle's numberplate. The camera measures a vehicle's speed using either radio waves or piezoelectric strips embedded in the road. The photograph also records the time, date, location and speed of the vehicle. The film is recovered and processed at regular intervals, and notices and fines are issued to drivers. Photographed in London, UK.