IDRIS-an algorithm for our time?

Loop detection has been in use for many years and a number of algorithms have evolved around this technology. IDRIS (incident detection for road informatics and safety) builds on this work and applies loop detection technology in a new and unique way. IDRIS is a combination of algorithms based at out-stations and an in-station which monitors traffic conditions accurately at all flow rates, from zero vehicles per hour to saturation anywhere in the system. When an incident occurs, IDRIS raises the appropriate alarm, and as part of a comprehensive system can command cameras and set variable message signs. This paper puts IDRIS in context and presents the technology and infrastructure problems which have been overcome to produce a production system, as borne out by results obtained from an operational IDRIS system in North Wales