Automatic number plate recognition surveys capture information regarding vehicle licence plates for various purposes. A large amount of data is collected by cameras placed at specific locations. These capture high-quality images and sophisticated computer software algorithms produce information that can be used for various traffic surveys including journey time surveys, origin and destination surveys and parking surveys. Using ANPR technology reduces the need for on-site and video enumerators. ANPR can also be used for car park management, security applications and controlling access to different sites. It is also used to implement congestion charging schemes in some major cities.
The quality of the data produced is dependent on several factors. If the cameras are installed permanently, or for long-term surveys, they are often installed more effectively. These are less subject to variations in weather and lighting conditions, and vehicular occlusion (blocking) than cameras which are installed for short-term surveys.
The number of correct plate detections usually ranges from 90% to 99.9%.