Issues in Performance Assessment of Sign-Controlled Intersections

Abstract

The capacity, performance and level of service assessment of intersections controlled by stop and give-way signs has special importance in the context of traffic impact assessment where the choice of sign-controlled intersections rather than roundabouts or signalized intersections can be controversial due to significant cost differences. Such controversy can often be traced back to choices of input parameters by traffic analysts to represent driver gap acceptance behaviour at sign-controlled intersections. This paper reviews guidelines available for the choice of driver behaviour parameters affecting capacity of sign-controlled intersections towards clearer guidance for practitioners in relation to this difficult and important task in sign-controlled intersection analysis. A number of related issues are discussed including the relationship between driver gap acceptance parameters and the intersection geometry, implications of analytical capacity models used in Australia and overseas, and the level of service and performance measures used for sign-controlled intersection assessment. An example is given for comparing the effect of differences in gap-acceptance parameters given in Austroads Road Design and Traffic Management Guides and the US Highway Capacity Manual on analysis results.