My entry for the City Daily Photo theme day of yellow is speed camera. The one pictured above is sited just before John Mason school, in Abingdon, where there are also speed bumps, on the Wooton Road.

When speed cameras were introduced in Abingdon back in 1992 they were grey. A change in the law in 2001 meant speed cameras were given a yellow vinyl sheet to ensure they can be seen.

There are four fixed speed cameras in Abingdon – all yellow:
Drayton Road – 30 MPH
A4183 – Oxford Road – 30 MPH
Wooton Road – 30 MPH
Audlett drive – 40 MPH

Speed cameras use radar technology to measure how fast a vehicle is travelling and to trigger the camera to take two photos in quick succession. A powerful flash will illuminate the registration plate. It is rear facing so as not to blind drivers. There are also white calibration lines (5mph apart) on the roads surface. So there are two forms of detection: radar, and calibration.