curprev09:2509:25, 31 January 2022 Shantaram1talkcontribs m10,134 bytes0 In 1975, Congress passed the Metric Conversion Act, which declared metric as the preferred system of the United States, and the U.S. Metric Board was created to implement the conversion. America began testing road signs in kilometers under President Jimmy Carter, who supported efforts to go metric.undoTag: 2017 wikitext editor