ESTIMATING THE CRITICAL ASSESSMENT GAP FROM TRAFFIC MOVEMENTS

At unsignalised intersections, when making opposed turns at signalised intersections, when overtaking on two lane rural roads, drivers are assumed to be waiting for an acceptable gap before moving. This minimum acceptable gap for a particular driver is termed his critical gap. A driver population is usually represented by the mean critical gap which is termed the critical acceptance gap and is then used in the appropriate formula to estimate capacity and delay. This report is to document the techniques to be used to estimate the parameters for drivers' critical gaps using the maximum likelihood technique. (A)