Intelligent vehicle highway systems are currently being developed world-wide. One of the systems that are closest to market introduction is Intelligent Cruise Control. There are several implementations under practical testing, each with a different approach. The common basis, though, is a normal cruise control enhanced by a distance keeping function. This paper presents the evaluation of Intelligent Cruise Control within Prometheus regarding capacity effects. The system evolved from an advisory version to an active one with some braking capability; the primary definitions for safety distance, however, were kept. A microscopic traffic flow simulator was extended to deal with such equipped vehicles. Simulation then provided results about capacity and safety. They indicate that a reduction of capacity cannot be found; safety, however, is increased by a significant reduction of small headways. This leads to the conclusion that, in contrast to earlier studies, such systems can improve safety without sacrificing capacity. (A)
Abstract