USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Methods for Maintaining Traffic Sign Retroreflectivity


            
            In This Section
        Other Safety Areas
                Road Diets
                Lighting and Visibility
                                Overview
                Sign Retroreflectivity
                Pavement Markings
                Roadway Lighting
                Focused Approach to Safety
                Motorcyclist Safety
                Older Road Users
                                Overview
                Crash Facts
                Engineering and Training
                Federal and State Programs
                Community Resources
                Articles
                Work Zone Safety
                Transportation Safety Planning (TSP)
                
                REFERENCES
“FHWA Fiscal Year 2003 Performance Plan.” This document can be viewed at the Internet Web site: https://www.fhwa.dot.gov/reports/2003plan/.
	“Traffic Safety Facts 2005: A Compilation of Motor Vehicle Crash Data from the Fatality Analysis Reporting System and the General Estimates System.” Publication NO. DOT HS 809484 December 2006. This document can be viewed at the Internet Web site: http://wwwnrd.nhtsa.dot.gov/pdf/nrd-30/NCSA/TSFAnn/TSF2005.pdf
	Federal Highway Administration and The Bureau of Transportation Statistics, 2001 National Household Travel Survey, (23.3% of vehicle miles traveled occur between 7:00 pm and 6:00 am). This document can be viewed at the Internet Web site: http://nhts.ornl.gov.
	Staplin, L., Lococo, K., and Byington, S., *Older Driver Highway Design Handbook*. FHWARD-97-135, FHWA, Washington, D.C., 1998
	*Manual on Uniform Traffic Control Devices.* U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2003.
	Carlson, P.J. and H.G. Hawkins, Jr. *Updated Minimum Retroreflectivity Levels for Traffic Signs.* FHWA-RD-03-81. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2004.
	Carlson, P.J., G.H. Hawkins, Jr., G.F. Schertz, D.J. Mace, and K.S. Opiela. “Developing Updated Minimum In-Service Retroreflectivity Levels for Traffic Signs.” In *Transportation Research Record 1824,* TRB, National Research Council, Washington, D.C., 2003, pp. 133–143.
	Carlson, P.J. and H.G. Hawkins, Jr. *Minimum Retroreflectivity Values for Overhead Guide Signs and Street Name Signs.*FHWA-RD-03-82. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2003.
	American Society for Testing and Materials. *Standard Specification for Retroreflective Sheeting for Traffic Control.*ASTM D4956-04, West Conshohocken, PA, 2004.
	McGee, H.W. and S. Taori. *Impacts on State and Local Agencies for Maintaining Traffic Signs within Minimum Retroreflectivity Guidelines.* FHWA-RD-97-053, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1998.
	*Traffic Control Device Handbook.* Institute of Transportation Engineers, Washington, D.C., 1999.
	Hawkins, H.G., P.J. Carlson, G.F. Schertz, and K.S. Opiela. *Workshops on Nighttime Visibility of Traffic Signs: Summary of Workshop Findings.* FHWA-SA-03-002, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2003.
	Hildebrand, E. “Reduction in Traffic Sign Retroreflectivity Caused by Dew and Frost.” Proceedings from TRB’s 82nd Annual Meeting, Washington, DC, January 2003.
	Lagergren, E.A.*Traffic Sign Retroreflectivity Measurements Using Human Observers.*Report No. WA-RD-140.1, Washington State Transportation Center, Seattle, WA, 1987.
	Hawkins, H.G. and P.J. Carlson.“Results of Visual Evaluations of Sign Retroreflectivity Compared with Minimum Retroreflectivity Recommendations.” In *Transportation Research Record 1754,*TRB, National Research Council, Washington, DC, 2001, pp. 11–20.
	*How to Check Traffic Signs for Correct Reflectivity.* 3M Company, St. Paul, MN, 1957.
	McGee, H.W. and D.L. Mace. *Retroreflectivity of Roadway Signs for Adequate Visibility: A Guide.* FHWA-DF-88-001, FHWA, Washington, D.C., 1987.
	Bischoff, A. and D. Bullock. *Sign Retroreflectivity Study.* FHWA-IN-JTRP-2002-22, FHWA, Washington, D.C., 2003.
	Rasdorf, W.J., J.E. Hummer, E.A. Harris, V.P. Immaneni, and C. Yeom. *Designing an Efficient Nighttime Inspection Procedure to Ensure Motorist Safety.* FHWA/NC/2006-08, North Carolina State University, Raleigh, NC, 2006.
	Black, K.L., H.W. McGee, S.F. Hussain, and J.J. Rennilson. *Service Life of Retroreflective Signs.* Report No. FHWA-RD-90-101, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1991.
	Hawkins, H.G., P. J. Carlson, J.B. McCaleb, and C.R. McIlroy.*Impact of Minimum Retroreflectivity Values On Sign Replacement Practices.*FHWA/TX-97/1275-1F, College Station, TX, 1996.
	W.D. Ketola. “Durability Testing for Retroreflective Sheetings.” In *Transportation Research Record 1230,* TRB, Washington, D.C., 1989.
	Black, K.L., S.F. Hussain, and J.F. Paniati. “Deterioration of Retroreflection Traffic Signs.” *ITE Journal,* July 1992.
	D.A. Andersen. *Sign Retroreflectivity Study.*North Dakota State University, North Dakota DOT, 1993.
	W.D. Ketola. “Laboratory-Accelerated Versus Outdoor Weathering for Retroreflective Sheeting Specifications.” In *Transportation Research Record 1657,*TRB, Washington, D.C., 1999.
	Montebello, D. and J. Schroeder. *Cost Effectiveness of Traffic Sign Materials.*MN/RC-200012, Minnesota DOT, St. Paul, MN, 2000.
	Kirk, A.R., E.A. Hunt, E.W. Brooks. *Factors Affecting Sign Retroreflectivity.*SR514, Oregon DOT, Salem, OR, 2001.
	Nuber, L. and D. Bullock. *Comparison of Observed Sign Retroreflectivity Values with Proposed FHWA Minimums.* TRB Annual Meeting, Washington, D.C., 2002.
	Awadallah, F.*Durability of Retroreflective Signs.* Doctoral Dissertation–University of Maryland–Department of Civil Engineering, College Park, MD. 1987.
	Kirk, A. R., E.A. Hunt, and E.W. Brooks. *Factors Affecting Sign Retroreflectivity.*Final report submitted to OR Department of Transportation, Salem, OR. 2001.
	Wolshon, B., R. Degeyter, and J. Swargam. *Analysis and Predictive Modeling of Road Sign Retroreflectivity Performance.*16th Biennial Symposium on Visibility and Simulation, Iowa City, IA. 2002.
	*Advance Notice of Proposed Amendments to the MUTCD: Minimum In-Service Retroreflective Performance of Traffic Control Devices.*Federal Register, Volume 50, Number 81, pp. 16,515–16,517, April 26, 1985.
	United States Department of Transportation and Related Agencies Appropriations Act of 1992, Public Law 102–388, 106 Statute 1520, Section 406.
	Mace, D.J., K. Perchonok, L.E. Pollack. *Traffic Signs in Complex Visual Environments.*FHWA-RD-82-102, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1982.
	Mace, D.J., R.B. King, and G.W. Dauber. *Sign Luminance Requirements for Various Background Complexities.*FHWA-RD-85-056, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1985.
	Mace, D.J., R.S. Hostetter, L.E. Pollack, and W.D. Zweig. *Minimal Luminance Requirements for Official Highway Signs.* FHWA-RD-86-151, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1986.
	McGee, H.W. and D.J. Mace. *Retroreflectivity of Roadway Signs for Adequate Visibility: A Guide.* FHWA-DF-88-001, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1988.
	Mace, D.J., P.M. Garvey, and R.F. Heckard. *Relative Visibility of Increased Legend Size vs. Brighter Materials for Traffic Signs.*FHWA-RD-94-035, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1994.
	Paniati, J.F. and D.J. Mace.*Minimum Retroreflectivity Requirements for Traffic Signs.*FHWA-RD-93-077, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., October 1993.
	Paniati, J.F. and D.J. Mace. Minimum *Retroreflectivity Requirements for Traffic Signs, Summary Report.*FHWA-RD-93-152, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., October 1993.
	McGee, H.W. and J.F. Paniati. *An Implementation Guide for Minimum Retroreflectivity Requirements for Traffic Signs.*FHWA-RD-97-052, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1998.
	McGee, H.W. and S. Taori. *Impacts on State and Local Agencies for Maintaining Traffic Signs within Minimum Retroreflectivity Guidelines.* FHWA-RD-97-053, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1998.
	Carlson, P.J. and H.G. Hawkins, Jr. “Minimum Retroreflectivity Values for Overhead and Street Name Signs.” In *Transportation Research Record 1794,*TRB, National Research Council, Washington, D.C., 2002, pp.38–48.
	Farber, E. and C. Matle. PCDETECT: A Revised Version of the DETECT Seeing Distance Model. *Transportation Research Record 1213.*Transportation Research Board, National Research Council, Washington, D.C., 1989.
	Blackwell, H.R. “Contrast Thresholds of the Human Eye.” *Journal of the Optical Society of America,*Volume 36, Number 11, November 1946.
	Mercier, C.R., C. Goodspeed, C.J. Simmons, and J.F. Paniati. “Evaluation of Proposed Minimum Retroreflectivity Requirements for Traffic Signs.” In*Transportation Research Record 1495,* TRB, National Research Council, Washington, D.C., 1995.
	Goodspeed, C.H. and C.R. Mercier. *Nighttime Sign Visibility Performance.*Unpublished Draft Final Report, Federal Highway Administration, Washington, D.C., November 1993.
	A.F. Bildstein, Jr. *The Effect of Environmental Illumination on Traffic Sign Conspicuity and Retroreflectivity.* Master of Science Thesis, College of Engineering and Mineral Resources, West Virginia University, Morgantown, WV, 2001.
	Black, K.L., H.W. McGee, S.F. Hussain, and J.J. Rennilson. *Service Life of Retroreflective Signs.* Report No. FHWA-RD-90-101, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 1991.
	Black, K.L., H.W. McGee, and S.F. Hussain. *Implementation Strategies for Sign Retroreflectivity Standards.* NCHRP Report 346, Transportation Research Board, Washington, D.C., 1992.
	Carlson, P.J. and H.G. Hawkins, Jr. *Minimum Retroreflectivity Values for Overhead Guide Signs and Street Name Signs.* FHWA-RD-03-82. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2003.
	Carlson, P.J. and H.G. Hawkins, Jr. *Updated Minimum Retroreflectivity Levels for Traffic Signs.* FHWA-RD-03-81. U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2004.
	Carlson, P.J., G.H. Hawkins, Jr., G.F. Schertz, D.J. Mace, and K.S. Opiela. “Developing Updated Minimum In-Service Retroreflectivity Levels for Traffic Signs.” In *Transportation Research Record 1824,* TRB, National Research Council, Washington, D.C., 2003, pp. 133– 143.
	Hawkins, H.G., P.J. Carlson, G.F. Schertz, and K.S. Opiela. *Workshops on Nighttime Visibility of Traffic Signs: Summary of Workshop Findings.* FHWA-SA-03-002, U.S. Department of Transportation, Federal Highway Administration, Washington, D.C., 2003.
	P.J. Carlson. *A Model for Estimating Traffic Sign Illuminance and Luminance as a Function of Pavement Reflectance.* Doctorate of Philosophy, Texas A&M University, College Station, Texas, 2002.
      
  Book traversal links for REFERENCES
      ‹ APPENDIX A. ESTABLISHMENT OF MINIMUM MAINTAINED TRAFFIC SIGN RETROREFLECTIVITY LEVELS
                    Up
                
                Book:Methods for Maintaining Traffic Sign Retroreflectivity
              CHAPTER 1. INTRODUCTION
                CHAPTER 2. RETROREFLECTIVITY MAINTENANCE METHODS
                CHAPTER 3. ASSESSMENT METHODS
                CHAPTER 4. MANAGEMENT METHODS
                APPENDIX A. ESTABLISHMENT OF MINIMUM MAINTAINED TRAFFIC SIGN RETROREFLECTIVITY LEVELS
                REFERENCES U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us