The chart pictured below represents the minimum requirements for retro reflective sheeting and tape for signs and applications that are under the jurisdiction of the Federal Highway Administration (FHWA) and the Manual of Uniform Traffic Control Devices (MUTCD). These changes were implemented in 2009. Although the MUTCD guide was most recently updated in 2022, for sign reflectivity levels, there have been no changes. Note that the levels below represent minimum standards set at the federal level. States will most likely have higher standards. The deadlines for compliance have all passed. The summary after the chart below will explain what the chart means for different types of signs.
- Assess the signs on their roads and develop a replacement plan within four years of the final ruling. (January 22, 2012)
- Replace non-compliant warning and regulatory signs within seven years of the final ruling. (January 22, 2015)
- Replace guidance and street name signs within ten years of the final ruling. (January 22, 2018)
On the left hand side of the chart above you find the color combinations used for the different types of signs. (sign color) Running left to right along the top of the chart you find the type of reflective sheetings available for signs. To the right running up and down are the overhead and ground mounted categories. In the center of the chart, you see the minimum reflectivity levels that must be maintained for each type of sheeting used. When you see an asterisk, that means that the color next to it cannot be used for that particular type of sign. When the chart says black, it means a non reflective black.
Explanation of W* ; G > 7 from chart above –
- W means white.
- * means type 1 sheeting cannot be used for this type of sign.
- G > 7 means that for green, type 1 can be used, but must exceed 7 candelas.
Explanation of W > 250 ; G > 25 from chart above –
- W > 250 means white prismatic sheeting type 3-10 can be used but must exceed 250 candelas.
- * means for white type 1, 2, or 3 sheeting cannot be used for this type of sign.
- G > 25 means that green can be used in all types, but must exceed 7 candelas.
As an example, if you want to sheet and letter an overhead sign on an interstate, your color choices are a green background with white letters. For the white, you cannot use type 1, type 2, or type 3 glass bead sheeting. For the green you can use any of those, but candelas (brightness) must be above the number listed to the right of the G. Notice that for a post mounted sign, the requirements are type 2 or above.
The minimum contrast ratio is also important. This simply means that the candelas or reflectivity of one color must exceed the other by a certain factor. For example, the white stop on a stop sign must be 3 times brighter than the red on the sign. If you use the same type of material for both color this contrast is usually achieved automatically. However, if you used a prismatic red background which reflects at 105 candelas, and an engineer grade white that reflects at 75 candelas, then you would not hit the 3 to 1 ratio.
The part of the MUTCD that covers is below –
mutcd-signs-updated 
Steven Cole (Economics, MBA – University of West Florida , Business & Innovation – Stanford University) 25 years of experience in the reflective safety business. Specializing in vehicle accident and rear end collision reduction through increased visibility.