The National Maximum Speed Limit (NMSL) was a provision of the federal government of the United States 1974 Emergency Highway Energy Conservation Act that effectively prohibited speed limits higher than 55 miles per hour (89 km/h). It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis and remained the law until 1995.

While federal officials hoped gasoline consumption would fall by 2.2%, the actual savings were estimated at between 0.5% and 1%.

The law was widely disregarded by motorists nationwide, and some states opposed the law, but many jurisdictions discovered it to be a major source of revenue. Actions ranged from proposing deals for an exemption to de-emphasizing speed limit enforcement. The NMSL was modified in 1987 and 1988 to allow up to 65 mph (105 km/h) limits on certain limited-access rural roads. Congress repealed the NMSL in 1995, fully returning speed limit-setting authority to the individual states.

The law's safety benefit is disputed as research found conflicting results.

The power to set speed limits historically belonged to the states. Prior to the NMSL, the sole exception to this occurred during World War II, when the U.S. Office of Defense Transportation established a national maximum "Victory Speed Limit" of 35 miles per hour (56 km/h), in addition to gasoline and tire rationing, to help conserve fuel and rubber for the American war effort. Although it was widely disregarded by many motorists, the Victory Speed Limit lasted from May 1942 to August 14, 1945, when the war ended. Immediately before the NMSL became effective, speed limits were as high as 75 mph (121 km/h). (Kansas had lowered its turnpike speed limit from 80 mph (130 km/h) before 1974.) Montana and Nevada generally posted no speed limits on highways, limiting drivers to only whatever was safe for conditions.

Richard Milhous Nixon (January 9, 1913 – April 22, 1994) was the 37th president of the United States, serving from 1969 to 1974. He was a member of the Republican Party who previously served as a representative and senator from California and was the 36th vice president from 1953 to 1961. His five years in the White House saw the end of U.S. involvement in the Vietnam War, détente with the Soviet Union and China, the first manned Moon landings, and the establishment of the Environmental Protection Agency. Nixon's second term ended early, when he became the only president to resign from office, following the Watergate scandal.

Nixon was born into a poor family of Quakers in a small town in Southern California. He graduated from Duke Law School in 1937, practiced law in California, then moved with his wife Pat to Washington in 1942 to work for the federal government. After active duty in the Naval Reserve during World War II, he was elected to the House of Representatives in 1946. His work on the Alger Hiss Case established his reputation as a leading anti-Communist, which elevated him to national prominence, and in 1950, he was elected to the Senate. Nixon was the running mate of Dwight D. Eisenhower, the Republican Party's presidential nominee in the 1952 election, and served for eight years as the vice president. He ran for president in 1960, narrowly lost to John F. Kennedy, then failed again in a 1962 race for governor of California. In 1968, he made another run for the presidency and was elected, defeating Hubert Humphrey and George Wallace in a close contest.

Nixon formally ended American involvement in Vietnam combat in 1973, and with it, the military draft, that same year. His visit to China in 1972 eventually led to diplomatic relations between the two nations, and he also then concluded the Anti-Ballistic Missile Treaty with the Soviet Union. In step with his conservative beliefs, his administration incrementally transferred power from the federal government to the states. Nixon's domestic policy saw him impose wage and price controls for 90 days, enforce desegregation of Southern schools, establish the Environmental Protection Agency, and begin the War on Cancer. Additionally, his administration pushed for the Controlled Substances Act and began the War on Drugs. He also presided over the Apollo 11 Moon landing, which signaled the end of the Space Race. He was re-elected with a historic electoral landslide in 1972 when he defeated George McGovern.

In his second term, Nixon ordered an airlift to resupply Israeli losses in the Yom Kippur War, a war which led to the oil crisis at home. By late 1973, the Nixon administration's involvement in the Watergate eroded his support in Congress and the country. On August 9, 1974, facing almost certain impeachment and removal from office, Nixon resigned the presidency. Afterwards, he was issued a pardon by his successor, Gerald Ford. In his almost 20 years of retirement, Nixon wrote his memoirs and nine other books and undertook many foreign trips, rehabilitating his image into that of an elder statesman and leading expert on foreign affairs. He suffered a debilitating stroke on April 18, 1994, and died four days later at age 81. Surveys of historians and political scientists have ranked Nixon as a below-average president. Evaluations of him have proven complex, as the successes of his presidency have been contrasted with the circumstances of his departure from office.