Project Title: Accommodating Nighttime Driver Needs with Improved Photometric Modeling

Sponsor: Excellence Center

Principle Investigator: Paul Carlson

Research Staff:

TTI Project Number: 220330

Start Date: 9/1/01

End Date: 8/31/02

Abstract: A congressional mandate has been set for FHWA to establish minimum retroreflectivity values for traffic signs. However, the relationship between vehicle headlamps, sign sheeting, and sign brightness is not completely understood. Photometric modeling techniques are available to estimate the nighttime performance of traffic signs but these models do no account for factors such as the combination of diffuse and specular pavement glare. These factors have neither been well documented or tested. Research is needed to identify such factors that impact the results of the theoretical photometric modeling efforts. This research will develop a more robust photometric model that is expected to form the ground work for more extensive research related to nighttime visibility of traffic signs and pavement markings.