The eighth part deals with microscopic traffic flow models, i.e., the manoeuvre models for following, lane changing and passing, and the more complete simulation models of a traffic flow embodying various manoeuvre models. Of the many car following models, the most important ones are discussed, the evolution being followed from simple and very mechanistic models to those embodying the limitations of drivers and vehicles. Investigation of car following models is broken down into determining drivers' possibilities of perception, examination of following behaviour in the laboratory and ordinary traffic. Some applications of the following models are given with the indication, development and evaluation of aids to driving. Lane changing and passing are analysed in terms of the space needed and available for these manoeuvres. This part discusses what is known of drivers' possibilities of perception relevant to these manoeuvres and what space is needed by reference to vehicle characteristics. Research in actual traffic mostly consists in determining the gap acceptance function indicating the chance of a driver starting the manoeuvre dependent upon certain conditions. More complete descriptions of the traffic flow on a microscopic scale can be achieved only with the aid of simulation models. In these, vehicle movements are simulated with a digital computer on the basis of deterministic and chance related rules. Besides the general aspects of these advancing models, a number of recent examples are discussed. The main applications are in the area of traffic operation. In addition, the possible relationship with road safety research is discussed. For part I-VII see IRRD abstracts nos 240606-240609 and 261941-3.
Samenvatting