Surveying commuters to obtain functional requirements for the design of a graphic-based traffic information system

The results of three studies, each designed to obtain functional requirements for the design of a graphics-based traveler information system, are reported. In the first study, the results of a survey are reviewed in which four commuter groups are identified with regard to the impact of traffic information on mode choice, departure time, and alternate route decisions. In the second study,the usability of five prototype traffic information screens are reported. In the last study, the results of a phone interview designed to provide an in-depth understanding of commuter traffic information needs is discussed.