Adequately maintained retroreflective signs improve highway safety and prevent
roadway departure crashes by bouncing light from vehicle headlights back toward
the vehicle and the driver's eyes, making the signs appear brighter and easier to
see and read. Because the retroreflective properties of traffic control devices
deteriorate over time, highway agencies need to actively manage the maintenance
of signs in order to ensure that they are clearly visible at night.
Minimum Retroreflectivity Levels for Blue
and Brown Traffic Signs [HTML,
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
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
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
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Guidance memorandum on the Roadside Design Guide - 4th Edition NEW!
Memorandum - Roadside Safety Hardware-Federal-Aid Reimbursement Eligibility Process NEW!
2009 MUTCD Compliance Dates Revised NEW!
FHWA Technical Advisory T 5040.40: Center Line Rumble Strips NEW!
FHWA Memo: Technical Advisories for Rumble Strips NEW!
Roadway Departure Safety Implementation Plans
Roadway Departure Countermeasures
Roadside Design: Steel Strong Post W-beam. A guidance memo was issued on May 17, 2010 on the height of guardrail for new installations. Guidance regarding existing guardrail will be developed in the next several months, in consultation with AASHTO’s Technical Committee on Roadside Safety.
Pavement Marking Retroreflectivity Notice of Proposed Rulemaking [HTML, PDF]
MUTCD Text of the Proposed Pavement Marking Retroreflectivity Standard
Summary of the MUTCD Pavement Marking Retroreflectivity Standard
Revised Assessment of Economic Impacts of Pavement Marking Retroreflectivity
Low Cost Treatments for Horizontal Curve Safety
The Safety Edge