Minimum Maintained Retroreflectivity Guideline Status

Because of reduced visibility at night, maintaining a safe and efficient transportation system becomes more challenging. Headlights and roadway lighting help to meet that challenge but are often not enough to fully meet the needs of drivers. This is where the technology of retroreflectivity helps. Retroreflectivity is the property of a material that returns light to the source. In the case of roadways at night, retroreflective materials may be traffic signs and pavement markings and the source is usually the headlights of a vehicle. Because a driver’s eyes are close to a vehicle’s headlights, some of the light returned from retroreflective materials reaches the driver’s eyes. The amount of light from an object reaching the driver’s eyes will have a great impact on how bright that object appears to the driver. This is important because traffic engineers use signs and markings to communicate important information to drivers. At night, if the signs and markings are not illuminated by other means, the retroreflective characteristics are important to increase the chance that a driver receives the information. Many things are being done to establish a standard of retroreflectivity.