Abstract
To enhance the efficiency of Advanced Traveler Information System, the relation between information and driver's behavior must be clarified. The aim of this study is to analyze driver's en-route path switch under the operation of travel time information system by laboratory experiment. The findings are as follows: 1) The operation of information system may cause drastic change in driver's route choice mechanism, becoming less dependent on travel result between origin and crossroads at which he/she reviews his/her choice. 2) It is likely that driver's route choice mechanism is influenced by information accuracy. If highly accurate information is provided continuously, route choice may become strongly dependent on information.
