The Impact of Advanced Traveler Information Services on Travel Time and Schedule Delay Costs

Abstract

This study develops an analytical dynamic mixed-equilibrium model to describe the transportation system performance with Route Planning and Guidance (RPG) services. The model considers travelers' departure time and route choices, and their propensity to subscribe to the service at different charge levels. We investigate the effect of the service charge on three parties: (i) equipped drivers; (ii) society in general; and (iii) the transportation management agency. The results show that the objectives of these parties are not always accommodative and may conflict with each other. Specifically, a numerical example illustrates that, under certain conditions, the society overall benefits from the service because all travelers are better off in terms of total generalized travel cost (i.e., travel time cost plus schedule delay cost). The surprising result, however, is that the network may become more severely congested. This seemingly paradoxical phenomenon is due to the much lower schedule delay cost incurred by travelers with RPG services, which more than compensates for the higher travel time associated with a more congested network. These results indicate the importance of considering RPG services from a more comprehensive perspective. In particular, it is important to include schedule delay cost as part of the benefit assessment of RPG services, in addition to the common measure of travel time cost.

Keywords:

• Dynamic Mixed-Equilibrium Traffic Assignment
• Route Planning and Guidance (RPG) Services

ACKNOWLEDGMENTS

This research is sponsored by the Competitive Earmarked Research Grant HKUST6283/04E from the Hong Kong Research Grant Council. We are grateful to the two anonymous referees for constructive comments.

Notes

^a It may be more intuitive to formulae this mixed-equilibrium problem as a nonlinear complementarity problem, rather than directly as a VIP. Such an approach can be found in Lo and Szeto (2002a).