Resources available for improving the maintenance of signs and sign supports for local roads and streets include:

1. Manual of Uniform Traffic Control Devices for Streets and Highways. Federal Highway Administration, 2009 Edition. Provides the standards and guidance for the size, shape, color, message, appropriate use and location for signs. The current manual is available on the Internet through the web site addressed: http://mutcd.fhwa.dot.gov.
2. Standard Highway Signs Handbook. Provides detailed drawings of signs provided in the MUTCD. Can be accessed at: http://mutcd.fhwa.dot.gov/ser-shs_millennium_eng.htm.
3. Ross, et al. "Recommended Procedures for the Safety Performance Evaluation of Highway Features," NCHRP Report 350, Transportation Research Board, 1993.
4. Carlson, Paul J. and Lupes, Matt S. Methods for Maintaining Traffic Sign Retroreflectivity, FHWA NO. FHWA-HRT-08-026, November 2007. http://www.fhwa.dot.gov/safety/other/visibility/methods-maintaining-traffic-sign-retroreflectivity
5. A Guide to Small Sign Support Hardware, AASHTO/AGC/ARTBA, 1988, which can be obtained at https://bookstore.transportation.org. (See also next reference.)
6. Manual for Assessing Hardware. American Association of State Highway and Transportation Officials, 2009. (Available for order at https://bookstore.transportation.org/Item_details.aspx?id=1539.)
7. Traffic Signing Handbook. Institute of Transportation Engineers, 1997.
8. Roadside Design Guide, 3rd Edition with updated Chapter 6. American Association of State Highway and Transportation Officials, January 1996.
9. FHWA web site for Retroreflectivity and Crashworthy Sign Supports: http://www.fhwa.dot.gov/safety.
10. Vegetation Control for Safety, A Guide for Local Highway and Street Maintenance Personnel. Available at https://www.fhwa.dot.gov/sites/fhwa.dot.gov/files/2022-06/vegetationfv1108.pdf.