Abstract
IMPACTS works on the principle of assessing how visible road space is being utilised at a particular moment in time and offers an alternative to loop detectors. Using a video surveillance camera road space is divided into cells and assessed as having either no traffic, moving traffic or stationary traffic. Details are given of the areas covered and the information generated. The use of the system to identify incidents is outlined. The system architecture is considered and the use of IMPACTS in a local autonomous monitoring system discussed. The advantages of the system are described and examples of field trials in London and Glasgow briefly outlined.