Driver Use of En Route Real-Time Travel Time Information

Communications and display technologies now permit the provision of key travel information to drivers in real time, using changeable message signs. The purpose of this project was to conduct human factors research to establish a basis for more effective provision of real-time travel time information. Such real-time travel time systems will only work well if they are designed with consideration of driver information needs and an understanding of the perceptual and cognitive aspects of motorist use of the signs. The project addressed these issues through various analytical and empirical activities. These included: (1) review of literature on travel time information and driver behavior; (2) identification of current practices and their rationale; (3) focus groups with drivers who commute along corridors with real-time travel time displays, in three cities with different signing practices and traffic system characteristics (Atlanta, Milwaukee, Seattle); (4) trip logs kept by commuters in the same three cities, documenting the driver’s experience with travel time displays and with influences on route choice, confidence in decisions, and other driver perceptions and beliefs; and (5) a laboratory study of the comprehension and interpretation of travel time displays. Recommendations for the design and use of en route real-time travel time displays were derived from the research findings.