Braking Behavior at Rural Expressway Intersections for Younger, Middle-Aged, and Older Drivers

High speed expressway intersections can be problematic for drivers of all ages. The purpose of this study is to evaluate driver performance at a high crash rate rural expressway intersection for three age groups: older (65 to 80), younger (18 to 25), and middle-aged drivers (35 to 55). This study reports preliminary findings associated with 30 drivers (ten drivers in each age group) who participated in an instrumented vehicle study. Of particular interest was to understand how braking behavior may differ on the approach to an expressway intersection prior to executing one of three different maneuvers (e.g., going across the intersection, left turn, and right turn). The specific performance measures include mean deceleration, initial brake point, brake pedal differential time (difference in initial to maximum brake pedal depression), and whether or not the driver came to a complete stop. Overall, individual differences based on age were observed. Both younger and older drivers showed more dramatic changes in the braking profile when compared to middle-aged drivers. Middle-aged drivers had the highest number of complete stops prior to entering an intersection and less dramatic or longer brake pedal differential times when compared to the other two age groups. Younger drivers were the least likely to come to a complete stop. This can be a potential safety concern given the lack of time allocated to make appropriate decisions. Future analyses will compare these findings to a low crash rate intersection as well as investigate how physiological measures such as heart rate variability may differ for these same age groups.