An Investigation of Streaking on Highway Traffic Signs

Report No: 73-R48

Published in 1974

About the report:

During a night inspection, dark streaks were observed on the faces of many reflectorized highway signs. Although the streaks were not visible during daylight, they substantially reduced the reflectivity of the signs at night. This study was initiated to determine the source of the streaks and to define remedial measures. An investigation revealed the streaks were caused by a residue of titanium dioxide from the paint on the wooden posts supporting the signs. As the paint deteriorated, the residue was transported down the sign faces by rain, and, subsequently, the titanium dioxide was deposited. The study concluded that clear coating would remove the streaks on existing signs, and it was recommended that in the future signs be installed with spacers, similar to nylon washers, between the sign panels and the painted posts.

Disclaimer Statement:The contents of this report reflect the views of the author(s), who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Virginia Department of Transportation, the Commonwealth Transportation Board, or the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. Any inclusion of manufacturer names, trade names, or trademarks is for identification purposes only and is not to be considered an endorsement.


Other Authors

R. N. Robertson

Last updated: February 7, 2024

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