Switzerland Radar Control, 1959 (b/w photo)

A traffic policeman tests a new radar, taken on 22 May 1959 in Zurich. On June 1, 1959, the Federal Council's decision on the maximum speed for motor vehicles came into force, imposing on the cantons of the obligation to carry out speed controls. The police command in Zurich had purchased the traffic radar of Telefunken for this purpose. With this measuring device, a radar beam was bundled over the road. When a vehicle passed the beam bundle, some of the beams were reflected to the device. There was a frequency difference between the wave emitted by the transmitter and the wave reflected by the vehicle, which depends on the speed of the vehicle. A police officer at the measuring station transmitted the measured value and the number of the vehicle by radio to the control station, which stopped faulty drivers.