Abstract
The design or redesign of urban intersections is a complex problem involving many variables. This paper, based on research work in Great Britain on the time settings of traffic signals, outlines a methodology which provides a quantitative basis for urban intersection design. Various factors, such as the traffic pattern, type of phase system, island and linemarking layout, presence of pedestrians and size of intersection, all affect the operational efficiency and safety of an intersection design. A Queuing Theory concept of practical capacity of an intersection is proposed.