The Downs-Thomson Paradox under transit dispatching and pricing schemes

Abstract

It is observed theoretically and empirically that the Downs-Thomson Paradox may occur in the sense that capacity expansion produces counterproductive effect on the overall network performance. This happens where the highway is in parallel of a transit line on the same corridor, and the shifting of traffic volume from transit system could make the highway more congested while transit service level also decreases due to shrinking revenue. The purpose of this paper is to investigate the occurrence of the Downs-Thomson Paradox considering monopoly transit dispatching and pricing schemes. We analyse the relationship between volume change and transit polices when highway capacity is expanded. Furthermore, the impact of capacity change on transit policies is presented. The conditions for the occurrence of Downs-Thomson Paradox are the most important findings. The results obtained will be demonstrated with numerical examples.