Nighttime Visibility Of Raised Pavement Markers And Wet Pavement Markings Under Service Conditions

Snow plowable raised pavement markers (RPMs) have been used in Ohio for the last four decades to provide visual guidance to motorists under inclement weather conditions. In recent years, due to the extended pavement resurfacing cycle employed by the Ohio Department of Transportation (ODOT), rare incidents have occurred where the aged pavement surface failed to provide adequate support to the RPM castings. As a result, ODOT adopted a rigorous plan to identify and replace loose RPMs. In addition, ODOT initiated this study to evaluate the performance of other alternative materials and determine whether they can provide equivalent or better delineation than the existing system. These materials included 3M all weather paint (AWP) and 3M 380 wet retroreflective (WR) extended season (ES) durable tape, in addition to the standard extruded thermoplastic that is commonly being used by ODOT on new asphalt surfaces. All materials were installed on Interstate 70 following an asphalt resurfacing project. The 3M AWP was installed on rumble strips and on the surface, while the 3M 380WR ES durable tape and the extruded thermoplastic were installed in groove and on the surface. These materials were evaluated for dry and wet retroreflectivity, dry and wet night visibility, daytime color, and durability for a period of 1.5 years. As expected, the extruded thermoplastic had the lowest retroreflectivity values and night visibility distances under wet conditions. The 3M AWP and the 3M 380WR ES durable tape provided high initial dry and wet retroreflectivity and night visibility. However, their performance was significantly compromised during the first and second winter seasons due to traffic and snow plowing activities. Finally, the RPMs had consistently higher wet night visibility distances than all pavement markings. Therefore, it was concluded that given the harsh environmental conditions in Ohio, it will not be cost effective to use 3M AWP or 3M 380WR ES durable tape as a replacement for RPMs.