§ Mr. ChopeTo ask the Secretary of State for the Home Department what action he is taking to ensure that speed cameras do not take pictures of a vehicle's reflection rather than the vehicle itself to calculate speed; and how many drivers he estimates have been wrongly penalised by reason of such errors. [149006]
§ Caroline FlintThe rigorous type approval process operated by the Home Office Police Scientific Development Branch (PSDB) is designed to ensure that speed camera evidence can be fully relied on
As a further precaution, however, all automatic static camera devices provide for a secondary check. This enables the officer viewing an apparent offence to make a judgment as to the vehicle's speed independent of the speed measured by the device. To enable this check, the device takes two photographs 0.5 seconds apart. The secondary check is performed by measuring the distance travelled along white lines painted on the road between the taking of the two photographs and calculating the vehicle's speed from these.
While it is technically possible for a camera to record a vehicle's reflection, rather than the vehicle itself, this is extremely rare in practice. Where it does occur, the difference revealed by proper application of the secondary check will make it obvious that there has been an error.