Pavement Marking Material Evaluation Study in Michigan

A project to evaluate various pavement-marking materials used for longitudinal delineation was conducted from March 1994 to July 1997 at 50 sites in five areas of Michigan. Pavement-marking materials used were water-borne paints, polyester, thermoplastics, and tapes. A total of 290 marking lines, including 140 with right and left edge lines, 45 with centerlines (two-way roadway), and 99 with lane lines, were used in the test. All lines were 4 in (10 cm) wide. The materials did not have a wide variation in retroreflectivity levels, with all materials showing high retroreflectivity values in the summer and lower values in the winter. Durability of test materials did not vary much, as each material maintained an average of more than 80% over the test period. Overall, the test-material degradation in retroreflectivity was 0.14% per day. The degradation rate was much greater in northern Michigan, where the snowfall was greater and more frequent. Traffic conditions did not correlate with the rate of change in retroreflectivity, and nighttime accident rates were not affected by the retroreflectivity levels in the ranges tested. It is concluded that water-borne paints are most cost-effective, because they retain good retroreflectivity (217.4 mcd/sq m/lx) levels, have reasonable durability (80%), have a long average time to failure (445 days), and are less costly than other materials with similar properties.