Fatal crash risk for older drivers at intersections.

Risk of fatal crash involvement was calculated for older drivers relative to drivers aged 40-49 in the United States during the years 1994-1995. The results indicated that drivers ages 65-69 were 2.26 times more at risk for multiple-vehicle involvements at intersections compared with 1.29 times more at risk in all other situations. The comparable figures for drivers aged 85 and older were 10.62 for multiple-vehicle involvements at intersections compared with 3.74 for all other situations. The relative crash risk was particularly high for older drivers at uncontrolled and stop sign-controlled locations; when traveling straight or when just starting to enter the intersection; and when the specific behavioral error in the crash was failure to yield. Countermeasures will likely involve reducing or simplifying the need to detect and evaluate moving traffic coming from the left and right when at intersections. This can be accomplished by traffic signals with protected left turns, four-way stop signs, and one-way streets. Whereas such devices involve significant cost in terms of dollars and travel delay, their cost-effectiveness may have to be revisited as the United States population continues to age.