Author Description

Raised pavement markers (RPM) are used in highway centerlines and edge lines as a traffic safety measure to provide more positive guidance for motorists in inclement weather and low light conditions. They are applied by highway agencies as delineation treatments to improve driver preview distances. The Indiana Department of Transportation has installed RPMs on selected roadway sections primarily as position guidance devices in order to better guide drivers in night conditions. In Indiana, RPMs are installed on all interstate highways and multilane divided highways. However, RPMs are used on only a few of the Indiana's two-lane highways. It was found that two-lane rural roads in Indiana experience relatively large number of fatal crashes. Thus, INDOT engineers would like to know if the safety on rural roads can be improved by placing RPMs on more two-lane highways. They would like to find out how effective the installed RPMs are in improving the safety of the motoring public. If the RPMs are effective, what criteria should be applied to identify the roadway sections and curves for RPM installations to improve safety? To address these questions and concerns, this synthesis study was conducted to search answers from the published literature and to identify and summarize the effectiveness of RPMs and the criteria for RPM placement. The objectives of this study were (1) to locate and assemble documented information on RPM applications; (2) to learn what practice has been used in other states for RPM applications; (3) to organize, evaluate, and document the useful information that is acquired; and (4) to provide recommendations on RPM applications based on the evaluated information. Currently, there is not a uniform guideline among state highway agencies for RPM placements on different types of highways. Some states install RPMs non-selectively on all state-maintained highways. Other states select roadways for RPM installations solely on the basis of traffic volumes or on