page_title: Metrication in the United States
section_title: 20th century
hierarchical_section_title: Metrication in the United States / History / 20th century
caption_attribution_description: English: A dual miles per hour and kilometers per hour sign, located along southbound Coral Ridge Drive and the Sawgrass Expressway in May 1992. This sign is no longer extant, as many of the kilometer signs were removed from use in the United States. This sign was likely erected in 1986, when the Sawgrass Expressway was opened to traffic. Photo taken with a Canon AE-1 camera, using a 55mm FD lens, and Kodak Tri-X film.
context_page_description: Metrication is the process of introducing the International System of Units, also known as SI units or the metric system, to replace a jurisdiction's traditional measuring units. Although U.S. customary units have been defined in terms of metric units since the 19th century, as of 2019 the United States is one of only three countries that have not officially adopted the metric system as the primary means of weights and measures.
  The United States has official legislation for metrication; however, conversion was not mandatory and many industries chose not to convert, and unlike other countries, there is no governmental or major social desire to implement further metrication.
  Although customary units are used more often than metric units in the U.S., the SI system is used extensively in some fields such as science, medicine, the military, automobile production and repair, and international affairs. Post-1994 federal law also mandates most packaged consumer goods be labeled in both customary and metric units.
context_section_description: The General Conference on Weights and Measures is the governing body for the modern metric system and comprises the signing nations of the Treaty of the Metre. The General Conference on Weights and Measures approved an updated version of the metric system in 1960 named Le Système international d'unités (International System of Units) and abbreviated SI.
  On February 10, 1964, the National Bureau of Standards (now known as the National Institute of Standards and Technology) issued a statement that it would use the metric system, except where this would have an obvious detrimental effect.
  In 1968 Congress authorized the U.S. Metric Study, a three-year study of systems of measurement in the United States, with emphasis on the feasibility of metrication. The United States Department of Commerce conducted the study. A 45-member advisory panel consulted and took testimony from hundreds of consumers, business organizations, labor groups, manufacturers, and state and local officials. The final report of the study concluded that the U.S. would eventually join the rest of the world in the use of the metric system of measurement. The study found that metric units were already implemented in many areas and that their use was increasing. The majority of study participants believed that conversion to the metric system was in the best interests of the United States, particularly in view of the importance of foreign trade and the increasing influence of technology in the United States.
  The U.S. Metric Study recommended that the United States implement a carefully planned transition to the principal use of the metric system over a decade. Congress passed the Metric Conversion Act of 1975 "to coordinate and plan the increasing use of the metric system in the United States". Voluntary conversion was initiated, and the United States Metric Board (USMB) was established for planning, coordination, and public education. The public education component led to public awareness of the metric system, but the public response included resistance, apathy, and sometimes ridicule. In 1981 the USMB reported to Congress that it lacked the clear Congressional mandate necessary to bring about national conversion. Because of this ineffectiveness and an effort of the Reagan administration—particularly from Lyn Nofziger's efforts as a White House advisor to the Reagan administration, to reduce federal spending—the USMB was disbanded in the autumn of 1982.
  The ending of the USMB increased doubts that metrication would really be implemented. Public and private sector metrication slowed even while competitiveness between nations and demands of global marketplaces increased.
  The American National Metric Council (ANMC) was established in 1973 by the American National Standards Institute (ANSI) as a non-profit, tax-exempt organization for planning and coordinating metric activity in all sectors of the U.S. economy. The ANMC became a separately incorporated organization in 1976. The ANMC was intended to facilitate U.S. metrication by maintaining a voluntary and orderly process that minimizes costs and maximizes benefits, and to provide information, forums, individual assistance, and other services for its subscribers. The ANMC attempted to coordinate the metric planning of many industrial sectors, unlike the USMB, which only attempted to implement the policy set forth in the Metric Conversion Act of 1975. After the formation of the USMB, committees of the ANMC submitted conversion plans for the chemical sector and for the instruments sector. These sector conversion plans were later approved by the USMB. From 1975 through 1987, the ANMC held a series of well-attended annual conferences. Subsequently, a series of National Metric Conferences, jointly sponsored by the ANMC, the U.S. Metric Association (USMA), the Department of Commerce, and the National Institute of Standards and Technology (NIST), were held from 1989 through 1993.
  Congress included new encouragement for U.S. industrial metrication in the Omnibus Foreign Trade and Competitiveness Act. This legislation ame
caption: A 1980s-vintage dual miles per hour and kilometers per hour sign, (formerly) located in Florida. (60 km/h ≈ 37.3 mph)
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