Design considerations for bus priority

Abstract

Paper presented at the 33rd Annual Southern African Transport Conference 7-10 July 2014 "Leading Transport into the Future", CSIR International Convention Centre, Pretoria, South Africa.

Providing priority to buses at traffic signals is widely used in Cities all over the world, but not in South Africa. The Department of Transport is rolling out Bus Rapid Transit (BRT) in all the major cities in South Africa, and providing priority to buses at signalized intersections, should form part of the overall design. A need exist to develop local experience and methodologies for the design of bus priority systems. The paper explains basic concepts such as passive and active bus priority as well as the technology required to implement active bus priority. Illustrations are provided of the basic active priority, namely extension of a stage, advancing a stage and skipping a stage. The potential benefit of bus priority, using these 3 methods are shown for 80 second cycle lengths and 120 second cycle lengths and the negative impacts, such as long cross road delay, is highlighted. The challenges of providing bus priority on routes where the block lengths are short and traffic signals are spaced less than 200 m to 300 m apart, are also highlighted. A logic for making the decisions related to bus priority is provided that aim to provide planners with a structured way to design bus priority, and also to act as a way of communication between bus schedulers, providers of controllers and other systems and traffic engineers.