The manual strictly divides its provisions into four categories to help engineers determine what is flexible and what is mandatory:
A recommended but not strictly mandatory practice. These statements use the word "should" . Federal Manual On Traffic Control Devices
Informational statements that provide background, data, or context without containing any mandates, recommendations, or permissions. 📖 Major Categories of Traffic Control Devices The manual strictly divides its provisions into four
Reduces the frequency and severity of crashes by providing clear, predictable guidance. or context without containing any mandates