What is the minimum size and colors allowed for Street Name Signs?
With the adoption of the 2009 National MUTCD, the lettering sizes and allowable colors for street name and some guide signs have changed.
The lettering needs to be a mix of upper and lower-case letters. The first letter of each name or abbreviation shall be upper-case and the rest of the lettering in the name or abbreviation shall be lower-case. The lettering height should be at least six inches (6”). For local roads with speed limits of 30 mph or less, the lettering height may be reduced to four (4”) inches. Street name signs have a white legend on a green background. The only other acceptable color combinations are a white legend on a blue or brown background or a black legend on a white background.
The Standard Highway Signs and Markings (SHS) Book, produced by the FHWA, shows the general layout of various signs and is available on the FHWA’s MUTCD webpage. It shows a 12 inch height for 6 inch letters and an 8 inch height for 4 inch letters. This sizing is confirmed by both FHWA and NYSDOT. For signs with six inch (6”) letters, the sign blank needs to be 12 inches high. For signs with four inch (4”) letters, the sign needs to be eight inches (8”) high.
While it is more legible if the supplementary lettering indicating the type of street (such as Street or Road) or direction (such as East) is the same size as the main legend, these may be reduced to 3 inches in height. Please note that the abbreviation (and smaller lettering) should only be used as a directional indicator. The full name with full height lettering should be used if this is the commonly used name.