Bright yellow speed cameras that can be seen easily by drivers are being introduced by police in an attempt to get motorists to slow down rather than collect fines from speeders.

The cameras are being adopted by 15 police forces after complaints from motorists that many were hidden behind trees or difficult to see because they were black.

John Spellar, the Transport Minister, said: "Our whole objective is to reduce the accident rate. One of the ways to do that is to reduce speeds on dangerous stretches of road. The object is to get people to slow down – not to catch them."

New guidelines state that no cameras should be obscured by bridges, signs or trees, and warning signs must be placed within 1km of cameras, which must be visible from 60 metres in 40mph zones and 100 metres where higher speed limits apply.

Fines from the new equipment will be invested in more cameras in areas where there are high risks of accidents.

Most police forces are expected to adopt them next year.