Link Travel Time Functions for Dynamic Network Models

Extensive resèarch has occurred in recent years on dynamic transportation network models, and especially on dynamic route choice models; these models have important applications in future ATIS and ATMS systems. However, most of the existing models lack a basis in traffic engineering. A significant problem for dynamic route choice is that the traditional BPR (Bureau of Public Roads, the predecessor of the Federal Highway Administration, U.S. DOT) volume-delay function is not applicable to a time-dependent traffic network. Meanwhile, since no proper dynamic link travel time functions exist, current dynamic route choice models assume various functional forms which are either too abstract or cannot provide realistic travel time estimates, even for a small network. Thus, it is becoming increasingly urgent to develop a set of timedependent link travel time functions for dynamic route choice problems.