Exploring Multiplier Effects Generated by Bus Lane Combinations

Numerous studies have explored design and evaluation of bus lane priority by using empirical, analytical, and simulation approaches. However, none attempted to understand how different bus lane combinations, such as continuous and discontinuous bus lane sections, and a different number of bus lane sections, affect bus performance and general traffic. This paper investigates operational effects of bus lane combinations to establish whether multiple bus lane sections create a multiplier effect in which a series of continuous bus lane sections creates more benefits than several single-lane sections. If a multiplier effect exists, it suggests scale economies in wider implementation of bus priority on a networkwide scale. Overall, results confirm that there is a multiplier effect; thus bus travel time benefits and general traffic travel time disbenefits are proportional to the number of links with a bus lane. The effect suggests a constant return to scale on continuous multiple sections. The results also suggest that converting a traffic lane to a bus lane when the upstream traffic volume exceeds the capacity of the remaining traffic lanes causes significant negative effects for buses and general traffic. In addition, negative general traffic effects of continuous bus lane combinations are lower than those for a similar number of discontinuous bus lanes. Bus delays at intersections approaching the bus lane tend to improve when upstream traffic volume does not exceed the capacity of remaining downstream traffic lanes. Policy implications and areas for future research are suggested.