American Association of State Highway and Transportation Officials. The Highway Safety Design and Operations Guide. Washington, DC. 1997.
American Association of State Highway and Transportation Officials. Roadside Design Guide, 4th Edition. Washington, DC. 2011.
Transportation Research Board, National Academy of Sciences. National Cooperative Research Program (NCHRP) Report 350, Recommended Procedures for the Safety Performance Evaluation of Highway Features. 1993.
US Department of Transportation, Federal Highway Administration. Manual on Uniform Traffic Control Devices. Washington, DC. 2009 Edition including Revision 1 and Revision 2, dated May 2012.