The estimation of arrival headways is fundamental to the modelling of gap acceptance processes for estimating capacities of sign-controlled traffic streams, roundabout entry streams and filter turns at signalised intersections. It is also essential in modelling both vehicle-actuated signal timings and queuing at all types of intersections for performance prediction. This paper considers a class of arrival headway distributions known as negative exponential, shifted negative exponential and bunched exponential. A description of the bunched exponential arrival headway distribution is presented, and the results of its calibration using real-life data for single-lane traffic streams and simulation data for multi-lane streams are given. Examples of gap-acceptance capacities and delays predicted by different exponential headway distributions are also presented.
AKÇELIK, R. and CHUNG, E. (1994). Calibration of the Bunched Exponential Distribution of Arrival Headways. Road and Transport Research 3 (1), pp 42-59.