Sources of Official Information

The official manual for signing in the United States is the Manual on Uniform Traffic Control Devices (MUTCD) published by the Government Printing Offices and approved as an American National Standard by the American National Standards Institute.

The MUTCD is a national standard, intended to ensure that signing is consistent throughout the US. Each state has adopted either the Federal MUTCD or a state Traffic Manual that governs traffic control devices for that particular state.

Functions of Traffic Signs

Traffic signs are devices placed along, beside, or above a highway, roadway, pathway, or other route to inform, guide, warn, and regulate the flow of traffic, including motor vehicles, bicycles, pedestrians, equestrians, and other travelers. Signs should only be placed when warranted by facts and engineering studies.

Sign Colors and Their Meanings

  • Red - Exclusively for stop signs, yield signs, multi-way supplemental plates, do not enter, and wrong way signs; for legend or symbols on certain regulatory signs, and as part of Interstate and certain State route markers
  • Black - Used as message on white, yellow, and orange signs
  • White - Used as a background for route markers, guide signs, and regulatory signs (except stop signs); and for the legend on brown, green, blue, black, and red signs
  • Orange - Used as background color for construction and maintenance signs
  • Yellow - Used as background color for warning signs and school signs
  • Brown and Green - Used for information guide signs
  • Blue - Used for information signs related to motorist services such as police services rest areas, and evacuation route markers

Sign Classifications

  • Regulatory signs give notice of traffic laws or regulations
  • Warning signs call attention to conditions on, or adjacent to, a highway or street that are potentially hazardous to traffic operations
  • Guide signs show route designations, destinations, directions, distances, service, points of interest, and other geographical, recreational, or cultural information