Retroreflectivity Requirements For Traffic Signs
For traffic signs to be effective, whether day or night, their visibility must be maintained. Because of this all cities, municipalities and local agencies are required to establish and implement a sign assessment method, with the goal to maintain minimum levels of sign retroreflectivity for all of their road signs.
Breaking News: Federal Government eliminates the 2012 retroreflectivity requirements for all cities!
What exactly does that mean? The most important effect of the new regulations is that cities will be able to replace traffic signs when they are worn out rather than replacing them by a specific deadline. This will save cities a considerable amount of money. When a traffic sign is replaced or a new sign is installed, the city will need to ensure that it meets minimum retroreflective levels.
What do these changes in regulations mean to you?
Cities will still be required to adopt an assessment or management method to maintain signs above minimum retroreflective levels. However, the compliance date has been extended to a date two years after the effective date of the final rule.
Accordingly, cities do not need to have an assessment or management method in play by Jan 22, 2012, rather, cities have at least another two years to develop a policy. Most importantly, the FHWA has eliminated the Jan. 22, 2015, and Jan. 22, 2018 compliance dates for replacement of signs that fail to meet minimum retroreflectivity standards.
First let’s talk about what exactly Retroreflectivity means…
Retroreflectivity is a term used to describe how light is reflected off of a surface and return to its original source (“retro”-reflector). Traffic sign sheeting materials now use technology with small glass beads or prismatic reflectors that allow light from vehicle headlights to be reflected back to the vehicle and the driver’s eyes, thus making the sign appear more bright and visible to the driver. For retroreflectivity to work properly, there needs to be a light source (vehicle headlights), a target (traffic sign), and a receptor (driver’s eyes).
Retroreflective Sheeting Materials
Sheeting types that can be used according to the new requirements are as follows:
- All prismatic sheeting materials may be used for all signs.
- High Intensity Beaded (Type III) and Super Engineer Grade (Type II) may be used for all signs except for the white legend on overhead guide signs.
- Engineer Grade (Type I) may be used for all signs except for:
- the white legend on guide signs,
- the white legend on street name signs, and
- all yellow and orange warning signs.
Even though a particular type of sheeting might initially meet the minimum retroreflectivity levels when new, it might quickly degrade to below the minimum retroreflectivity levels. The use of higher performance sheeting, even though it has a higher initial cost, might provide a better life-cycle cost for the agency.
The FHWA has developed a sheeting ID guide and has posted it at: http://safety.fhwa.dot.gov/roadway_dept/night_visib/
It’s All About Safety
Providing retroreflective delineation and signing is important as a means of reducing the higher nighttime crash rates. Signs that have sufficient retroreflectivity during nighttime conditions are especially beneficial to older road users. Safe and efficient highways are a benefit to the motoring public and to the health and viability of a community.
It is vitally important that traffic sign visibility be maintained
The Manual on Uniform Traffic Control Devices (MUTCD) published by the U.S. Department of Transportation – Federal Highway Administration, sets forth basic principles of traffic signs: namely to promote safety and efficiency on our public roads. Traffic signs notify motorists of regulations, provide warning to potential hazards on or near the roadway, and provide needed guidance to destinations.
Public agencies who have installed traffic signs also have the responsibility to maintain them through the life of the sign. Public agencies should devote resources to retain the visibility and legibility of traffic signs, as well as ensuring that signs remain properly mounted and in good working condition.
The MUTCD 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.
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.