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. Federal law requires compliance by all traffic control signs and surface markings on roads "open to public travel", including state, local, and privately owned roads (but not parking lots or gated communities).Frequently Asked Questions - General Questions on the MUTCD 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 and Markings. 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 FHWA on additions, revisions, and changes to the MUTCD. The current release of the MUTCD is the 11th edition released in December 2023.
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, and 4 years before World War II started in 1939. 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
Early 20th century
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 with travelers' direction and safety. Conflicts between these clubs frequently led to multiple sets of signs—sometimes as many as eleven—being erected on the same highway.
Government involvement did not occur until the late 1910s and early 1920s, when groups from Indiana, Minnesota, and Wisconsin began surveying roads to develop signage standards. They reported their findings to the Mississippi Valley Association of Highway Departments, which adopted their suggestions for the shapes of road signs in 1922. These suggestions included using a circle for railroad crossings, an octagon to signify a stop, a diamond for ordinary conditions of danger, a square for intermittent danger conditions, and a rectangle for regulatory or directional information.
In January 1925, Thomas Harris MacDonald, chief of the federal Bureau of Public Roads, published an article in which he argued that developing highway transportation in the United States to the "highest degree" would require five major innovations. Among them were "uniform markings and signs" and a "uniform color code". MacDonald argued that "drastic enforcement of uniform rules" as to "all those matters of law, regulation and safety devices which involve the human attributes in the operation of the vehicle" would improve safety on American highways, because in emergency situations, a driver and his vehicle must react as one on the basis of "reflex" and there is no time to think.
In January 1927, the American Association of State Highway Officials (AASHO) published the Manual and Specifications for the Manufacture, Display, and Erection of U.S. Standard Road Markers and Signs to set standards for traffic control devices used on rural roads. Despite the title, this manual did not have any guidance on pavement markings; at the time, the meaning of the now-obsolete phrase "road marker" overlapped with what modern speakers would call a "sign". In 1930, the National Conference on Street and Highway Safety (NCSHS) published the Manual on Street Traffic Signs, Signals, and Markings, which set similar standards for urban settings, but also added specific guidance on traffic signals, pavement markings, and safety zones. Although the two manuals were quite similar, in 1931 both organizations formed a Joint Committee to develop a uniform standard for both urban streets and rural roads; this standard was the MUTCD.
The original edition of the Manual on Uniform Traffic Control Devices for Streets and Highways was published in 1935 as a mimeographed document. In 1937, the manual was republished as a typeset document.
In 1942, the Joint Committee was expanded to include the Institute of Transportation Engineers (ITE), then known as the Institute of Traffic Engineers. During World War II, the second edition of the MUTCD was released as a War Emergency Edition. This included information on traffic control under blackout conditions and how to conserve materials needed for the war effort.
In 1948, three years after World War II ended, the third edition of the MUTCD was released. This edition had a different format and structure than the previous editions. Several road signs first assumed their current appearance in this edition. The most controversial issue during the early years of the MUTCD had been the color of center lines on roads. The 1948 MUTCD settled on white, but recommended yellow for double center lines on multi-lane highways and for center lines in no-passing zones.
Mid-20th century
In 1949, the United Nations Conference on Road and Motor Transport launched a research project to develop a worldwide uniform signage scheme. In 1951, the UN conducted experiments in the US to compare the effectiveness of national traffic sign standards from around the world. Signs from six countries were placed along the road for test subjects to gauge their legibility at a distance. The test strips were located along Ohio State Route 104 near Columbus, U.S. Route 250 and Virginia State Route 53 near Charlottesville, Minnesota State Highway 101 near Minneapolis, and other roads in New York. France, Chile, Turkey, India, and Southern Rhodesia reciprocated by installing MUTCD signs on their roads. In the US, the experiments attracted unexpected controversy and curious onlookers who posed a hazard. By September 1951, the experts working on the project were in favor of the American proposals for stop signs (at the time, black "STOP" text on a yellow octagon), "cross road", "left or right curve", and "intersection", but were still struggling to reach consensus on symbols for "narrow road", "bumpy or uneven surface", and "steep hill".
In 1953, after cooperating with the UN conference's initial experiments, the United States declined to sign or ratify the UN's then-proposed protocol for a worldwide system of uniform road signs. There were two major reasons behind this decision. First, most U.S. roads and streets were (and still are) under state jurisdiction. Second, the United States was developing modern controlled-access highways at the time (culminating in the creation of the Interstate Highway System in 1956), and the novel problems presented by such new high-speed highways required rapid innovations in road signing and marking "that would definitely be impaired by adherence to any international code". Despite the Americans' withdrawal from the research project, the experiments eventually resulted in the Vienna Convention on Road Signs and Signals of 1968.
The 1954 revision of the 1948 MUTCD changed the standard color of stop signs from yellow to red.
In 1960, the National Joint Committee on Uniform Traffic Control Devices was again reorganized to include representatives of the National Association of Counties and the National League of Cities, then known as the American Municipal Association. In 1961, the MUTCD was again revised to make yellow center lines mandatory for the two exceptions where they had previously been recommended. The 1961 edition was the first edition to provide for uniform signs and barricades to direct traffic around road construction and maintenance operations.
During the 1960s, United States Senator Abraham Ribicoff emerged as a prominent national advocate for highway safety, having previously championed the issue as governor of Connecticut. In an essay published in the July 1965 edition of The Atlantic Monthly, he argued that a lack of uniform standards between states contributed to highway deaths. For example, two of the worst deviations from the majority rule that no passing should be marked with a solid center line were Pennsylvania, which marked no-passing zones only with signs and not center lines, and Georgia, which marked them only with a yellow line on the shoulder.
In 1966, Congress passed the Highway Safety Act, , , which is now codified at et seq. It required all states to create a highway safety program by December 31, 1968, and to adhere to uniform standards promulgated by the U.S. Department of Transportation (USDOT) as a condition of receiving federal highway-aid funds. The penalty for non-compliance was a 10% reduction in funding. In turn, taking advantage of broad rulemaking powers granted in , the Department simply adopted the entire MUTCD by reference at . ((a)(1), also enacted in 1966, authorizes federal agencies to incorporate by reference technical standards published elsewhere, which means the agency may merely cite the standard and need not republish its entire text as part of the appropriate regulation.) Thus, what was formerly a quasi-official project became an official one. States are allowed to supplement the MUTCD but must remain in "substantial conformance" with the national MUTCD and adopt changes within two years after they are adopted by FHWA.
The 1971 edition of the MUTCD included several significant standards. The MUTCD imposed a consistent color code for road surface markings by requiring all center lines dividing opposing traffic on two-way roads to be always painted in yellow (instead of white, which was to always demarcate lanes moving in the same direction), and also required that all highway guide signs (not just those on interstate highways) contain white text on a green background. Orange was introduced as the standard color for traffic control in work zones.
Another major change in the 1971 MUTCD, inspired by the Vienna Convention, was a preference to adopt symbols on signs in lieu of words "as rapidly as public acceptance and other considerations permit." During what was then expected to be a transition period, the MUTCD allowed state highway departments to use optional explanatory word plaques with symbol signs and to continue using the previous standard word message signs in certain cases. Robert Conner, the chief of the traffic control systems division of the Federal Highway Administration during the 1970s, believed that symbol signs were "usually more effective than words in situations where reaction time and comprehension are important." Conner was active in the Joint Committee and also represented the United States at international meetings on road traffic safety. However, several American traffic safety experts were concerned that American drivers would not understand the Vienna Convention's symbols, which is why the MUTCD allowed for explanatory word plaques. Most of the repainting to the 1971 standard was done between 1971 and 1974, with a deadline of 1978 for the changeover of both the markings and signage.