Requirement #2 - Command Attention
A traffic control device must command the attention of the motorist to be effective. Physical factors that help signs command attention are size, shape, location, and visibility. The Standard Highway Signs manual provides design guidelines to ensure that fabricated signs are uniformly standardized and therefore are recognizable to motorists.
The Federal Highway Administration has established standards, in both the MUTCD and the Standard Highway Signs (SHS) manual, for the design and application of all traffic signs. The SHS manual is intended for use by all traffic authorities involved with the fabrication, installation, and maintenance of traffic signs and is available for downloading from the MUTCD website. The manual provides detailed drawings of the actual sign panels to promote uniformity in design throughout the United States, whereas the MUTCD states the required overall sign size based on roadway classification.