The Manual on Uniform Traffic Control Devices for Streets and Highways (usually referred to as the Manual on Uniform Traffic Control Devices, abbreviated MUTCD) is a document issued by the Federal Highway Administration (FHWA) of the United States Department of Transportation (USDOT) to specify the standards by which traffic signs, road surface markings, and signals are designed, installed, and used. In the United States, all traffic control devices must legally conform to these standards. The manual is used by state and local agencies as well as private construction firms to ensure that the traffic control devices they use conform to the national standard. While some state agencies have developed their own sets of standards, including their own MUTCDs, these must substantially conform to the federal MUTCD. The MUTCD defines the content and placement of traffic signs, while design specifications are detailed in a companion volume, Standard Highway Signs. This manual defines the specific dimensions, colors, and fonts of each sign and road marking. The National Committee on Uniform Traffic Control Devices (NCUTCD) advises the FHWA on additions, revisions, and changes to the MUTCD. The United States is among the countries that have not ratified the Vienna Convention on Road Signs and Signals. The first edition of the MUTCD was published in 1935, 33 years before the Vienna Convention was signed in 1968. The MUTCD differs significantly from the European-influenced Vienna Convention, and an attempt to adopt several of the Vienna Convention's standards during the 1970s led to confusion among many US drivers. History At the start of the 20th century—the early days of the rural highway—each road was promoted and maintained by automobile clubs of private individuals, who generated revenue through club membership and increased business along cross-country routes. However, each highway had its own set of signage, usually designed to promote the highway rather than to assist in the direction and safety of travelers. In fact, conflicts between these automobile clubs frequently led to multiple sets of signs—sometimes as many as eleven—being erected on the same highway. Government action to begin resolving the wide variety of signage that had cropped up did not occur until the late 1910s and early 1920s when groups from Indiana, Minnesota, and Wisconsin began surveying existing road signs in order to develop road signage standards. They reported their findings to the Mississippi Valley Association of Highway Departments, which adopted their suggestions in 1922 for