Safety Effectiveness of Advance Street Name Signs

Low-cost safety strategies that states may implement as part of their Strategic Highway Safety Plans need to be evaluated. FHWA organized a Pooled Fund Study of 26 states to evaluate several low-cost safety strategies, including the installation of advance street name signs at signalized intersections. This study investigates whether advance street name signs reduce crashes related to way-finding (i.e., rear-end and sideswipe crashes) at signalized intersections. Geometric, traffic, and crash data were obtained for signalized intersections at 82 sites in Arizona, 65 sites in Massachusetts, and 46 sites in Wisconsin. To account for potential selection bias and regression to the mean, an empirical Bayes before–after analysis was used. The analysis found no significant effect of advance street name signs on total crashes. However, the analysis indicated a significant reduction in sideswipe crashes, including a 27% reduction in Massachusetts and a 10% reduction for the three states combined. A disaggregate analysis was also conducted to identify differential effects. On the basis of conservative cost estimates, a reduction of just 0.01 crash per intersection year would achieve a 2:1 benefit–cost ratio. Given the low cost of this strategy and the potential to enhance way-finding, the use of advance street name signs is justified, particularly at three-legged intersections and locations with relatively large average annual daily traffic or a large expected number of crashes.