Introduction to Sign Retroreflectivity
What are the New Requirements?
The MUTCD requires signs to be either illuminated or made with retroreflective sheeting materials. Most signs in the U.S. are made with retroreflective sheeting materials. These materials degrade over time and therefore have a limited life. Until now, there has been little information available to determine when signs need to be replaced based on retroreflectivity.
The 2003 MUTCD Edition, Revision 2, now identifies minimum retroreflectivity values that must be maintained. If a sign falls below this minimum value, it needs to be replaced. Different types and quality of sheeting materials are available, and the effective life of a sign (its retroreflectivity) will depend largely upon which material is chosen.
To meet the requirements, all agencies must implement a traffic sign maintenance program that is consistent with the predetermined methods outlined in the MUTCD, or hire a traffic engineer to develop a customized sign maintenance program that is based on an engineering study. Agencies will not necessarily need to measure retroreflectivity levels of all their signs, but do need to implement a program that regularly evaluates and assesses the nighttime performance of their signs.