An automatic incident detection (aid) system, using computer based algorithms to identify the traffic disturbances following an incident, is under test on a site on the M1 motorway in Bedfordshire. It incorporates the TRRL algorithm hiocc. The hiocc algorithm looks for several consecutive seconds of high detector occupancy, such as would be caused by stationary or slow-moving vehicles, to detect incidents in high traffic flows. A time lapse television surveillance system has been used to check the causes of alarm messages and to determine whether any incidents have been missed. Eighteen months experience with hiocc has shown it to be an efficient incident detection algorithm on the M1 test site detecting hazards caused by slow-moving vehicles, roadworks and accidents, with very few false alarms. (Author/publisher)
Abstract