AASHTO - American Association of State Highway and Transportation Officials
Scope
Purpose of Traffic Control Devicessupport:The purpose of traffic control devices@ as well as the principles for their use@ is to promote highway safety and efficiency by providing for the orderly movement of all road users on streets and highways throughout the Nation.Traffic control devices notify road users of regulations and provide warning and guidance needed fer the safe@ uniform@ and efficient operation of all elements of the traffic stream.Standard:Traffic control devices or their supports shall not bear any advertising message or any other message that is not related to traffic control.support:Tourist-oriented directional signs and Specific Service signs are not considered advertising; rather. they are classified as motorist service signs.