||Visibility Needs of Motorists During Wet Night Conditions
Benjamin H. Cottrell, Jr.
||Pavement markings convey regulations and warnings and provide tracking information and guidance to drivers. In fact, pavement markings provide much of the visual information needed by drivers to navigate safely in a variety of conditions including daylight, darkness, and adverse weather. The retroreflectivity of the usual pavement markings is lower under wet night conditions, and this is of particular concern to VDOT's Traffic Engineering and Materials divisions. In 1997, VDOT conducted a customer service survey. More than 3,000 Virginians were asked to rate their satisfaction with seven aspects of Virginia's transportation system in a telephone survey conducted by Coopers and Lybrand. Nighttime visibility, especially in wet conditions, was identified as needing additional attention. The purpose of this project is to determine the visibility needs of drivers during wet night conditions. The research will seek to answer the following questions: 1. What level of retroreflectivity do drivers need under various rain conditions? 2. What levels of retroreflectivity are current pavement markings and markers capable of producing under various rain conditions? The findings will be used to develop performance measures for evaluating the wet night retroreflectivity of pavement delineation devices. These performance measures will lead to the primary purpose and concept of this research: the development of a performance-based specification for these devices that is based on the visibility needs of drivers during wet night conditions.|