National Older Driver Research and Training Center

Examining issues surrounding older driver assessment, remediation, rehabilitation, and the use of alternatives to the car.

Publications - ICADI


The Impact Of Roadway Intersection Designs On The Driving Performance In An On-the-road Test Of Young And Senior Adults

Presenters: Classen, Sherrilene; Shechtman, Orit; Garvan, Cynthia; Stephens, Burton; Davis, Ethan


The Federal Highway Administration (FHWA) proposed guidelines for highway design to increase the safe driving ability of older drivers, but little empirical evidence exists to support these guidelines. Using kinematics measures from an instrumented vehicle and on-road evaluations, this study investigated the effects of improved versus unimproved intersections to determine if negotiation of these intersections is safer for both older (65-85) and younger (25-45) drivers in North Florida. Preliminary results indicated significant differences in driving performance between the improved and unimproved road conditions. Kinematics measures showed that four maneuvers had significantly greater maximum yaw, lateral acceleration and combined acceleration for the unimproved conditions, and significantly greater speed for the improved conditions. Increased side forces indicated poorer lateral stability and increased speed indicated greater confidence during the turn. Behavioral measures showed that drivers had significantly fewer errors for two of the improved left-turn maneuvers, and fewer total errors overall with older drivers having a higher mean number of errors. These findings suggested that the FHWA guidelines for safe road conditions result in safer driving by older and younger adults.