Evaluation of Retroreflectivity Measurement Techniques for Profiled and Rumble Stripe Pavement Markings

Abstract

The objectives of this research were to evaluate the influence of stepping distance on average, dry retroreflectivity measurements of profiled and rumble stripe pavement markings through the use of a portable (handheld) retroreflectometer and to compare these measurements with ones made with a mobile retroreflectometer. The retroreflectivity of flat, profiled, and rumble stripe thermoplastic pavement markings was evaluated by several means with the use of multiple handheld retroreflectometers and a mobile retroreflectometer. Stepping distance was found to have no practical influence on averaged retroreflectivity measurements of evaluated marking types when measured in accordance with ASTM E 1710-05. The addition of an extended base on the handheld retroreflectometer, the hand-leveling of the device, or both were suitable ways to maintain the retroreflectometer in the plane defined by the tops of the pavement marking profiles for proper measurement. The vertical structure of the profiled and rumble stripe pavement markings did not increase the dry retroreflectivity measurements of the markings. The flat segments between the depressions of the rumble stripe pavement marking were found to produce the highest retroreflectivity readings of any part of the rumble stripe. A properly calibrated, mobile retroreflectometer operated by an experienced user gave dry retroreflectivity measurements that were not practically different from those obtained with a handheld retroreflectometer in accordance with ASTM E 1710-05. These findings validated the capability of the handheld retroreflectometer to accurately measure profiled and rumble stripe pavement markings.