One year performance of longitudinal waterborne paint pavement markings used on primary and secondary roads of South Carolina

Pavement markings are made retroreflective so that roads are more visible. But retroreflectivity degrades over time due to a number of factors. Although the Federal Highway Administration has yet to finalize minimum standards for retroreflectivity, the degradation of pavement marking retroreflectivity can be detrimental to safety. The primary objective of this thesis was to use statistics to develop and validate regression models to predict the degradation of water borne pavement marking retroreflectivity. This will provide the South Carolina Department of Transportation (SCDOT) a systematic means to determine when markings should be replaced.;To achieve this objective an LTL-X handheld retroreflectometer was used to take retroreflectivity readings at 60 test sections spread throughout South Carolina. Data collection started in May 2008 and ended by July 2009. Four rounds of data were collected during the one year duration. Site collected data was entered into Excel and analysis done using the Statistical Analysis Software.;The data collected from sites were categorized based on pavement marking color (White or Yellow) and pavement marking type (Edgelines, Centerlines and Skiplines). A total of eight models were developed to evaluate the degradation in marking retroreflectivity. These models were validated using the field collected data to know the accuracy of the models.;Regression models were also developed to study the effect of directionality of paint laying for yellow centerlines on retroreflectivity values. The study found that directionality does affect retroreflectivity.;The validated models will help SCDOT in predicting the lifecycle of water borne pavement marking paints which can help them plan their replacement schedules well in advance leading to cost saving and ensuring quality.