Road Weather Management Program
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Best Practices for Road Weather Management Version 2.0

Title:

Reductions in Traffic Sign Retroreflectivity Caused by Frost and Dew

Abstract:

A study of in-service traffic signs was undertaken to quantify the average effects of frost and dew on their retroreflective capabilities. The results were then compared to proposed minimum retroreflectivity standards recently developed by FHWA-sponsored research for inclusion in the Manual on Uniform Traffic Control Devices. Although the effects of frost and dew were found to be variable, average reductions in retroreflectivity levels of 79 and 60 percent were found, respectively. The findings are significant enough that they should be considered in the development of the final version of the FHWA national standards. Furthermore, those jurisdictions subject to frequent cycles of frost/dew should review usage guidelines governing the grade of sign materials used allowing for expected loss of retroreflectivity.

Source(s):

82nd Transportation Research Board (TRB) Annual Meeting, University of New Brunswick (Canada). For an electronic copy of this resource, please direct your request to WeatherFeedback@dot.gov.

Date: 2003

Author:

Hildebrand

Keywords:


Ice/Frost
Dew

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