The Federal Highway Administration (FHWA) publishes the Manual on Uniform Traffic Control Devices (MUTCD) establishing national standards for all traffic signs. All agencies that maintain public roadways use the MUTCD to ensure signs and markings are uniform in their design and placement.
Until recently, the MUTCD did not address when a traffic sign should be replaced based on how well it reflects light, also known as its retroreflectivity. Traffic signs use small glass beads or prismatic reflectors to reflect a sign’s information back to the driver’s eyes. Read More.