Link between Pavement Marking Retroreflectivity and Night Crashes on Michigan Two-Lane Highways

Abstract

The retroreflectivity of longitudinal pavement markings is expected to improve safety on rural highways. However, the few available research reports focused on the relationship between retroreflectivity and safety have found mixed results. New insights into such a relationship by using generalized linear mixed-effects models are provided. With this tool, the research team developed and analyzed a database of rural two-lane roads in Michigan, including night crashes, roadway characteristics, and retroreflectivity of pavement markings. The analysis used crash data from 2003 through 2008 for select types of nighttime crashes. The analysis found a statistical association between pavement marking retroreflectivity and nighttime safety. A significant statistical interaction between white edgeline and yellow centerline retroreflectivity indicated that these variables performed interdependently. In general, sites with higher retroreflectivity were found to be associated with fewer crashes than sites with lower retroreflectivity for both types of markings. This research also found that sites with low centerline retroreflectivity (compared with edgeline retroreflectivity of the same road) were associated with more crashes.