REFLECTIVITY OF PAVEMENT MARKINGS: ANALYSIS OF RETROREFLECTIVITY DEGRADATION CURVES

The intent of this project was to develop retroreflectivity degradation curves for roadway pavement markings. To accomplish this objective, this study utilized a vehicle-mounted Laserlux retroreflectometer to take measurements on approximately 80 test sections throughout Washington state. The resulting retroreflectivity values from roadways with similar average annual daily traffic (AADT) and environments displayed a significant amount of variability. Best-fit trendlines were extrapolated to determine when each category of paint would fall below a selected minimum threshold of 100 mcd/m 2 /lux and require repainting. Unfortunately, given the variability of the data observed to date, it may not be possible, even with the collection of more data, to create striping performance predictions that have a high level of statistical confidence. The data do not suggest conclusively that the existing WSDOT striping schedule should change. According to that schedule, long line painted markings should be painted at least once a year, and heavy wear, long line pavement markings should be painted at least twice a year. None None DISCLAIMER The contents of this report reflect the views of the authors, who are responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Washington State Department of Transportation. This report does not constitute a standard, specification, or regulation. 8 Yellow waterborne paint in Western Washington with low AADT (<7,500) 20 9 White waterborne paint in Western Washington with low AADT (<7,500). The intent of this project was to develop retroreflectivity degradation curves for roadway pavement markings. These degradation curves would be used to forecast the performance of pavement markings and to help determine a cost-effective schedule for reapplying them. To accomplish these objectives, this study utilized a vehicle-mounted Laserlux® retroreflectometer to take measurements on approximately 80 test sections throughout Washington state. The project included test sections of waterborne and solvent-based paint, as well as a limited number of durable material sections. The degradation curves focus on the waterborne and solvent-based paint. Data collection for the project took On the basis of the literature review of previous retroreflectivity studies, a minimum acceptable retroreflectivity threshold of 100 mcd/m²/lux was selected. Best-fit trendlines were extrapolated to determine when each category of paint would fall below the minimum threshold and require repainting. The resulting retroreflectivity values from roadways with similar average annual daily traffic (AADT) and environments displayed a significant amount of …