Researchers found that overall perception-reaction times in such situations for drivers 20 to 40 years old were 3.6 seconds compared with 4.5 seconds for 65 to 69 year olds and 5.5 seconds for drivers 70 and over. Only 18 percent thought their reaction times had slowed over the last ten years. FHWA is giving special attention to problems older drivers encounter on freeways when they must make such high-speed decisions as merging and changing lanes. These complex driving tasks require an ability to attend to visual input from more than one direction and make accurate, quick decisions. Intersections present another instance where driving requires quick and accurate decision making and complex maneuvering in response to numerous stimuli.
Statistics show that seniors are over-represented in intersection accidents.
Interviews with older drivers revealed problems with skewed intersections, particularly where intersection angles of more or less than 90 degrees created a design that required tight left turns. To find ways to decrease accident rates at intersections for older drivers, FHWA is conducting field studies with offset left-turn lanes and increased curb radii. The research had revealed that spatial skills deteriorate as drivers age. FHWA will continue to work toward finding the best applications of IVHS and ATIS for an aging driving population. Future Efforts FHWA is working on a highway design handbook summarizing research findings on older drivers, and they will continue to make older driver concerns a high priority in their research and design efforts.