Driver behaviour at non-urban T-junctions
The accident situation in Great Britain is reviewed, and the process of gap acceptance is described. Studies of gap acceptance behaviour at intersections are discussed according to the factors which were investigated, and some of the literature on pedestrian gap acceptance is reviewed. The use of the traffic conflicts technique in this country is also outlined. Two different methods of collecting data at junctions are described and compared, and the advantages of a system which incorporates both video techniques and a microprocessor-based system developed at RHC are detailed. Empirical results on the relationships between gap acceptance parameters and various factors are presented: the effects of major road speeds and flow, manoeuvre time of turning vehicles, class of vehicle in each traffic stream, gender of driver and presence of passengers are investigated. Two models of gap acceptance by queues of vehicles are then discussed. Preliminary results from a large scale study to test the validity of a conflict simulation model developed at RHC are reported, which indicate that the model may be used to compare accident risk in different situations. Some examples of the ways in which safety at junctions varies with particular parameters are given, using results from the model. Details of the computer programs used to analyse gap acceptance data from T-junctions are appended.