Working paper:

• Zhu, Shanjiang and David Levinson (2010), Do people use the shortest path? An empirical test of Wardrop’s first principle. Presented at 4th International Symposium on Transportation Network Reliability, July 2010, Minneapolis, MN.

Most recent route choice models, following either the random utility maximization or rule-based paradigm, require explicit enumeration of feasible routes. The quality of model estimation and prediction is sensitive to the appropriateness of the consideration set. However, few empirical studies of revealed route characteristics have been reported in the literature. This study evaluates widely applied shortest path assumption by evaluating morning commute routes followed by residents of the Minneapolis – St. Paul metropolitan area. Accurate GPS and GIS data were employed to reveal routes people used over an eight to thirteen week period. Most people do not choose the shortest path. Using three weeks of that data, we find that current route choice set generation algorithms do not reveal the majority of paths that individuals took. Findings from this study may provide guidance for future efforts in building better route choice models.

JEL-Code: R41, R48, D63

Keywords: Transportation planning, route choice, travel behavior, link performance