Information on the new regulation can be found at the website link below:
The background from the site states;
The Manual on Uniform Traffic Control Devices, or MUTCD, establishes uniformity and standards for traffic signs on public roads. Recently adopted language in the MUTCD now requires all agencies to adopt a sign maintenance program, which in turn will help agencies meet new minimum retroreflectivity requirements for the traffic signs they have installed.
All agencies, large and small, that own and maintain traffic signs, are required to adhere to these new requirements for their traffic signs. Implementing these requirements may also involve beginning a new sign maintenance program.