California Partners for Advanced Transportation Technology

Advanced Traveler Information Systems (ATIS) are being developed to provide travelers with real-time information about traffic conditions. To evaluate the benefits of ATIS products and services, questions concerning potential market, usage, and travel response must be addressed. This paper focuses on en-route travel response to ATIS. The main objective is to explore how travelers deal with unexpected congestion and how they might respond to qualitative, quantitative, prescriptive and predictive information. Data on travelers’ route switching decisions are obtained through a survey of California Bay Area automobile commuters. The effects of various factors, such as sources of congestion information (radio traffic reports versus observation), trip characteristics, and route attributes on traveler response to unexpected congestion, are investigated. Future response to ATIS technologies is explored using stated preferences, i.e., hypothetical ATIS scenarios.

A combined reported and stated preference model of traveler response is developed. The results show that expected delay on usual route, travel time on alternate routes, perceived congestion level on alternate routes, and information sources are important determinants of travel decision changes in response to unexpected delays. The modeling methodology identifies the effect of experience and behavioral inertia on choices, and captures inherent biases in the stated preference responses. Overall, travelers are more likely to respond to specific quantitative delay information.