The positioning of the ANPR camera is of utmost importance in order that the system operates effectively. Poor positioning can result in less than 50% recognition, whereas optimum positioning can result in the majority of plates being recognised.

Where ANPR is set up using a single camera at a barrier entrance, the camera should be located in a bollard of around 1m in height to allow direct viewing of the oncoming vehicle. Similarly, if a single camera is responsible for the surveillance of one lane of traffic, the ANPR unit should be pole-mounted at a distance of between 18 and 30m from the oncoming vehicles. The use of multiple cameras to cover multiple lanes, for example on a motorway, is a more complex operation.

CCTV cameras have long been an integral part of our town centres, but these are now being installed with ANPR technology. As a result, the cameras need to be adapted and re-positioned to allow optimum use of the technology. The shutter speed on a standard CCTV camera is 1/50sec, but ANPR cameras should have a shutter speed setting of 1/1000sec, though a shutter speed of 1/500sec would be adequate for traffic travelling at up to 40mph. Once the cameras have been fitted with ANPR their position needs to be checked to ensure an adequate percentage of recognitions.

Police vehicles installed with ANPR cameras usually have them swivel mounted, which means that the cameras can capture images to the front and sides of the vehicle.