Sign Retroreflectivity

Research

• Minimum Retroreflectivity Levels for Blue and Brown Traffic Signs [HTML, PDF 1MB]
  This report provides research findings supporting recommendations for minimum maintained retroreflectivity (MR) levels for white-on-blue and white-on-brown signs. The report also includes findings of an investigation of MR levels needed for complex visual conditions, such as glare from oncoming headlamps and fixed roadway lighting. [Publication No. FHWA-HRT-08-029]

• Minimum Retroreflectivity Levels for Overhead Guide Signs and Street-Name Signs [HTML, PDF 837 KB ]
  This 2003 report prepared for the FHWA by Texas Transportation Institute presents the results of a study that investigated the nighttime visibility needs of drivers for viewing overhead guide sign and street name signs. [Publication No. FHWA-RD-03-082]

• Updated Minimum Retroreflectivity Levels for Traffic Signs [HTML, PDF 837 KB]
  This 2003 report prepared by Texas Transportation Institute for the FHWA updates the minimum levels of traffic sign retroreflectivity for certain types of traffic signs (regulatory, guide, and warning), which were originally generated in 1993. [Publication No. FHWA-RD-02-081]

• Maintaining Traffic Sign Retroreflectivity: Impacts on State and Local Agencies [HTML, PDF 417 KB]
  This 2007 report prepared by the FHWA’s Turner Fairbank Highway Research Center analyzes the administrative, fiscal, implementation, and tort liability concerns of State and local transportation agencies in relation to the adoption of minimum maintained retroreflectivity levels for traffic signs. The results are based on input received at four workshops held during the summer of 2002. [Publication No. FHWA-HRT-07-042]

• Workshops on Nighttime Visibility of Traffic Signs: Summary of Workshop Finding
  This report presents the results of four workshops sponsored by the FHWA in 2002 to obtain input from stakeholders regarding the issues and alternatives associated with minimum levels of in-service sign retroreflectivity. About 100 invited representatives attended the workshops, including city, county, and State transportation agencies, professional organizations, agency attorneys, and FHWA staff. [Publication No. FHWA-SA-03-002]

• Turner-Fairbank Photometric and Visibility Laboratory
  The FHWA Turner-Fairbank Highway Research Center’s Arens Photometric and Visibility Laboratory (PVL) enables researchers to evaluate the photometric and colorimetric properties of signing and marking materials, including fluorescent materials. Studies of human-centered systems related to visibility issues are also performed in this laboratory.

For hard copies of documents with publication numbers, please send a request to report.center@dot.gov and include the publication number and title, along with the number of copies and your mailing address and phone number. Requests will be filled based on availability.