Driver Performance at Two-Way Stop-Controlled Intersections on Divided Highways

The goal of this study is to examine differences in driving performance at rural expressway intersections with respect to age (younger, middle-aged, and older) and intersection (high- and low-crash area). Such intersections occur where a median-divided highway meets a two-lane, stop-controlled minor road. One intersection was identified as a high-crash area with horizontal curves; the other one was a low-crash area with no curves. All participants were asked to perform three driving maneuvers (i.e., going straight across, making a left and a right turn) from the two-lane minor roads. Age and intersection differences immediately before entering and within these intersections were examined. Sixty drivers participated in the study and were divided evenly between the younger (18 to 25), middle-aged (35 to 55), and older (65 to 80) groups. Data for each participant were collected from an on-road study in an instrumented vehicle. Results showed that both older and younger drivers were likely to run stop signs and less likely to yield at medians when compared with middle-aged drivers. The effect of age difference on driving performance before intersection entry was consistent with previous studies. Middle-aged drivers approached the high-crash intersection with significantly less brake pedal differential time and were less likely to run stop signs compared with actions by drivers in other age groups. Higher traffic volume and more complicated road geometry at the high-crash intersection may be factors contributing to the differences observed.