• Image 05
  • Image 04
  • Image 01
  • Image 02
  • Image 03



Traffic signs, while often considered peripheral design elements, play a critical role in communicating a variety of information to users of the transportation system.  Signs are used to guide, warn, regulate, and convey information to vehicular and pedestrian traffic along the roadway.

The Manual on Uniform Traffic Control Device (MUTCD) provides guidance on the design and placement of signs, including the size of the sign and text, placement along the roadway, and standard information to be conveyed.  Most states, including Missouri, use the MUTCD as the primary guide for developing roadway signage.  Some states, such as Illinois, provide supplemental guidance that builds upon the information in the MUTCD.  Engineers and contractors also use standard drawings, similar to those provided by the Missouri DOT, to ensure that signs are designed and constructed appropriately.

In the various place types discussed in this guide, traffic signs are often one of many traffic control devices that users must process while navigating streets.  Therefore, it is important to design and position signs in a manner which ensures that users have enough information to safely and efficiently navigate the arterial street network without becoming distracted or overwhelmed.

Decorative street sign
Credit: CH2M HILL

The MUTCD specifications help ensure a minimum level of nationwide traffic sign uniformity.  Uniformity is a critical component of effective traffic sign communication, as users are better able to recognize and respond to familiar signs.  Although some jurisdictions may wish to modify the standard sign types to be more attractive, the majority of traffic signs are required to conform to the MUTCD specifications.  One exception is street name signs, which can be customized and used to help create a theme or identity for a place.  Many agencies are developing artistic street signs, such as the Washington Avenue sign in downtown St. Louis shown at right, to add character to the streetscape.

The ITE Traffic Handbook indicates that traffic control devices, including traffic signs, should:

  • Meet a need
  • Command attention
  • Convey a clear and simple meaning
  • Command respect of the road users
  • Give adequate time for proper response/reaction