Pavement Overlay Effectiveness and Optimal Timing Determination Using Receiver Operating Characteristic Curve and Data Envelopment Analysis Methods.

This study uses the Receiver's Operating Characteristic (ROC) curve and Data Envelopment Analysis (DEA) methods to analyze the factors that affect the performance of asphalt concrete overlays on flexible pavements. The ROC curve method is used to compare the relative importance of the parameters and to determine the appropriate overlay timing. Pavement performances after overlays are categorized as either effective or ineffective, in order to satisfy the binary outcome required by the ROC method. The DEA method is used to help distinguish the effective overlays from the ineffective ones based on the pavement conditions within the first six years after overlay. The results show that timing of overlay and snowfall amount are important to overlay effectiveness for both high traffic and low traffic volume pavement, while overlay thickness is important only for high traffic volume pavements. The optimal condition threshold to perform overlay is slightly higher on low traffic volume pavements than on high traffic volume pavements. Thin (2 inches or less) overlays are not effective on high traffic volume pavements.