Reflecting on Road Signs Road signs are an essential part of Oregon s transportation system, providing travelers with information to help ensure safe, orderly and predictable traffic movement. The investment in signs is substantial. To manage these assets, ODOT needs to be able to plan for sign replacement due to normal wear and physical damage or loss. Retroreflectivity Signs need to be visible and readable at night as well as during the day.
Signs use various types of retro-reflective sheeting.
The sheeting consists of tiny prisms or spheres in a weather-resistant, transparent plastic film. Depending on their color, signs exhibit different levels of retroreflectivity. Signs with a white or yellow background have the highest intensities, while green and red signs have lower intensities. The Federal Highway Administration and ODOT have set standards for minimum retroreflectivity. The standards vary depending on the color of the sheeting material.