Trip scheduling in urban transportation analysis

Evidence is presented for the importance of endogenous scheduling. The effects of ignoring it and the recent advances in modeling it are also described. These advances include analysis of the welfare benefits associated with policies that modify scheduling choices. There are many ways that models can be made more realistic. One way is to embed them in a network with endogenous route choice. Another is to incorporate more fully the heterogeneity that is found in the empirical studies of scheduling choice, both in parameters and in unobservable preferences for particular schedules. Yet another is to allow capacity to be random, depending, for example, on weather conditions or traffic accidents. Another desirable extension, awaiting better empirical measurements, is to incorporate the reliability of travel schedules. Despite these limitations, the analysis is sufficiently advanced, and it can be incorporated into practical traffic studies and into standard economic theories of traffic congestion. Doing so promises to bring new predictive accuracy and new insights into transportation analysis.