Part 5 of the MUTCD

Part 5 of the MUTCD establishes standards, guidelines, and supplementary information defining the use of special traffic control for low-volume roads in the United States.

For the purposes of the MUTCD, "low-volume road" is defined as a roadway lying outside of built-up areas of cities, towns, and communities with a annual average daily traffic (AADT) volume of less than 400 vehicles per day.