Pricing and logit-based mode choice models of a transit and highway system with elastic demand

The objective of this paper is to enhance the insights into transport pricing mechanism and the corresponding mode choice behavior in a simple bi-modal transportation system with elastic demand. This system comprises a mass transit parallel to a bottleneck-constrained highway between a residential area and a workplace. We derive and compare three pricing schemes: the arbitrarily fixed pricing, the first-best pricing for a social optimum of the system, and the second-best pricing in the case of incapability of road toll. It is shown that the first-best pricing requires to implement a road toll and a transit fare simultaneously, and the optimal transit fare for the second-best solution should be set to be a weighted sum of the marginal external costs between auto and transit commuters. A numerical example is presented to illustrate how the pricing policies affect the demand implementation, the mode choice behavior and the efficiency of the whole transportation system.