Motorists warned about motorway yellow average speed cameras

Motorists could expect fine if they miss yellow cameras (Image: National Highways)

Motorists have been warned to expect a fine and points on their licence if you fail to heed brightly coloured cameras put up around roadworks.

Average speed cameras are painted yellow and work by calculation the time  taken for a vehicle to travel over a certain distance. This is opposed to other types of speed cameras that calculate the speed of a vehicle as it passes a specific point.

Average speed cameras are equipped with infra-red illuminators, allowing them to work in all weather conditions, all day hours a day.

According to National Highways, when you see a fixed speed limit sign on the roads, together with an ‘average speed check’ sign this means that vehicles exceeding that speed limit are detected by average speed enforcement cameras.

If you don’t want to get caught our, ensure you are driving at or below the speed limit on the road.

Cameras will be set up in at least two locations. Each vehicle is detected by an 'entry camera' and an 'exit camera', which records their registration plate using Automatic Number Plate Recognition (ANPR) as it passes the entry and exit cameras, then matches the vehicle data recorded.

It calculates the average speed from the known distance between the entry and exit camera locations and the time taken for the vehicle to pass.If the average speed exceeds the legal speed limit, the system retrieves the ANPR data and recorded images of the passing vehicle together with date and time stamps from both cameras, creating an evidence record which is sent to the police.

According to National Highways, the data will be deleted for all vehicles passing the cameras which have not exceeded the average speed limit.

Each camera must go through a robust government testing and certification process to ensure that evidence from it can be admissible in UK courts.If there are electronic display signs for speed, opposed to the static ones, they are usually blank or turned off.

National Highways said “in exceptional cases” there may be an illuminated variable speed limit displaying overhead, or to the side of the road, while you're still within the average speed limit zone around roadworks. In this case, it’s recommended that motorists apply with the lower of the speed limits indicated.