GIVING THE OLDER DRIVER ENOUGH PERCEPTION-REACTION TIME

Many types of behavior slow with age, and older drivers require more time to process information and make decisions. How greater response time requirements relate to the design of the highway environment and to features of new in-vehicle technologies is discussed. The design requirements for many different aspects of roadway geometrics and traffic control devices are based on design driver perception-reaction times. However, without knowing how much slower older drivers are than the design driver, it is difficult to determine whether they are adequately protected by current design practice and, if not, what the desired change in design should be. Attempts to address this have been hampered by the lack of directly relevant data, the situation-specific nature of certain findings, and the older driver's ability to compensate for declines in basic skills. Also discussed are the promise and problems of new in-vehicle technologies for providing the older driver with adequate time to act. These intelligent vehicle highway systems (IVHS) may speed navigational decision making and recognition of hazards and maneuver requirements. However, the possibility for interfering with quick responding also arises, and IVHS systems might disadvantage the older driver in other ways.