Retroreflective Raised Pavement Markers: A Two-Year Field Evaluation in Texas (1946-3F)

This report documents the results of field testing seventeen types of retroreflective raised pavement markers (RRPMs) installed in August 1992 at four interstate locations around San Antonio, Texas. Reflectivity measurements were taken periodically at each site using a portable retroreflectometer. These data were supplemented with laboratory reflectivity measurements from RRPMs taken from each site and sent to the TxDOT Material and Testing Laboratory in Austin, Texas.|Study results indicate that most of the RRPMs experienced significant losses in reflectivity over short periods of time. Under the range of traffic conditions examined, many RRPMs dropped below approximate minimum reflectivity thresholds after less than six months in the field. Certain RRPM designs did perform considerably better than others. In general, RRPM reflectivity was related to the cumulative vehicular exposure since installation. Using approximate RRPM purchase and installation cost data from TxDOT, it appears that the more durable (and expensive) RRPMs can be justified from a cost-effectiveness perspective once AADT levels on the roadway reach 10,000 vehicles per lane per day.