Development and potential of system optimized route guidance strategies

The authors examine the traffic engineering potential and limitations of routeing strategies that are system optimized, as opposed to routeings that minimize the travel times of individual drivers. This examination is based on a simple two-route traffic network. The user- and system-optimum traffic assignments are illustrated for this network, and the sensitivity and magnitude of any differences between the two are examined. An incremental traffic assignment technique that can find system-optimized routes in a traffic engineering context is introduced. This can be utilized within existing traffic models or directly in a route guidance algorithm, where vehicles are assigned to the network as packets (increments) of size 1. It is concluded that there are potential savings in total network travel time if system- vs. user-optimized routeing strategies are considered.<>