The national 55 mph speed limit was in effect from January 2, 1974 through November 28, 1995. President Richard Nixon signed it into law during the 1973 oil crisis, and President Bill Clinton signed the repeal nearly 22 years later, handing speed-setting authority back to the states.
Why It Started in 1974
On October 19, 1973, the Organization of Arab Petroleum Exporting Countries imposed an oil embargo on the United States in retaliation for American support of Israel during the Yom Kippur War. Prices nearly quadrupled, climbing from about $2.90 per barrel to $11.65 by January 1974, and gasoline shortages sent drivers into long lines at filling stations across the country.1Federal Reserve History. Oil Shock of 1973-74 Highway driving was an obvious place to look for immediate fuel savings.
Nixon signed the Emergency Highway Energy Conservation Act on January 2, 1974. The law encouraged states to cap speeds at 55 mph and made continued receipt of federal highway trust funds contingent on doing so.2The American Presidency Project. Statement on Signing the Emergency Highway Energy Conservation Act In practice, no highway project could be approved in any state whose speed limit exceeded 55.3Federal Highway Administration. January 2 – FHWA By Day – Highway History Before the law, limits varied widely, with some states allowing 80 mph. That variety vanished almost overnight as states complied rather than lose federal money.
Congress relied on the Spending Clause to condition highway funding, and courts later held it could have imposed the limit directly under the Commerce Clause. When Nevada challenged the law as unconstitutionally coercive, the Ninth Circuit upheld it, reasoning that if Congress could mandate speed limits outright, it could achieve the same result through conditional funding.
What the Limit Actually Did
The most striking effect had little to do with oil. Traffic fatalities dropped from 54,052 in 1973 to 45,196 in 1974, a decline of about 16.4%.4Department of Transportation. Motor Vehicle Traffic Fatalities and Fatality Rates, 1899-2023 Nearly 9,000 lives were saved in a single year. Fewer miles driven during the fuel shortage accounted for some of the drop, but the fatality rate per mile also fell sharply, so lower speeds clearly contributed.
Fuel savings were another story. Nixon’s signing statement projected nearly 200,000 barrels of fuel saved per day.2The American Presidency Project. Statement on Signing the Emergency Highway Energy Conservation Act The Department of Transportation’s own research later found the limit cut gasoline consumption by roughly 1%, and some studies put it at half that. Once the crisis eased, the conservation rationale looked thin, and supporters shifted to safety as the main defense of the law.
Widespread Noncompliance
Drivers ignored 55 almost from the start, and compliance eroded further over time. A Government Accountability Office report described the situation as “a game and a battle of wits between the police and the public,” with motorists using Citizens Band radios to warn each other about speed traps and radar detectors to evade enforcement.5GAO (Government Accountability Office). Speed Limit 55: Is It Achievable? At least one state was barred by its own laws from using radar for speed enforcement at all.
Federal monitoring told the same story in numbers. Average speeds and 85th-percentile speeds had dipped after the law took effect, then began climbing again by 1977.6Bureau of Transportation Statistics. The Effectiveness of the 55 MPH National Maximum Speed Limit Western states with long, straight, lightly traveled highways were especially resistant, since 55 felt absurd on roads engineered for much higher speeds.
The 1987 Compromise on Rural Interstates
By the mid-1980s, political pressure to relax the limit had built up. On April 2, 1987, Congress overrode President Reagan’s veto of the Surface Transportation and Uniform Relocation Assistance Act by a single vote in the Senate, 67-33.7Federal Highway Administration. President Ronald Reagan and the Surface Transportation and Uniform Relocation Assistance Act of 1987 The act let states raise limits to 65 mph on rural interstates built to Interstate standards outside urbanized areas.
Thirty-eight states adopted the higher limit on some or all of their eligible rural interstates.8Bureau of Transportation Statistics. The Effects of the 65 mph Speed Limit During 1987: A Report to Congress Urban interstates and non-Interstate roads stayed capped at 55. The partial fix satisfied some critics and frustrated others who felt the federal government still had no business setting speed policy.
The 1995 Repeal
The national limit ended on November 28, 1995, when President Clinton signed the National Highway System Designation Act.9The American Presidency Project. Statement on Signing the National Highway System Designation Act of 1995 Section 205(d) repealed the National Maximum Speed Limit compliance program entirely, letting each state set whatever speed limits it wanted, or none at all.10Federal Highway Administration. NHS Designation Act of 1995 Federal highway funding no longer turned on speed limits.
The rollout was quick. The amendments applied to each state on the 10th day after enactment, with a narrow exception for states whose legislatures were not in session, which could delay until 60 days after the legislature next convened.11U.S. Government Publishing Office. National Highway System Designation Act of 1995 Public Law 104-59 Congress also directed the Secretary of Transportation to study the costs and benefits of the repeal, including crash-related deaths and injuries in states that raised their limits, with a report due by September 30, 1997.
What Replaced the National Limit
States moved fast. Most raised maximums on rural interstates to 70 or 75 mph within a few years. Research published in the late 1990s found fatalities on interstates rose by about 15% in the 24 states that increased their limits, with fatality rates roughly 17% higher after the changes. Deaths on non-interstate roads, where limits generally stayed the same, were essentially unchanged.12PubMed. Changes in Motor Vehicle Occupant Fatalities After Repeal
Speed limits vary widely today. A toll section of State Highway 130 in Texas holds the national high at 85 mph. Idaho, Montana, Nevada, South Dakota, Utah, and Wyoming post 80 mph on certain rural highways, and most states allow at least 70 mph on their fastest roads. A few states set no statewide maximum for certain road types, leaving the decision to engineering studies and local authorities.
The Department of Transportation still weighs in on speed policy through its National Roadway Safety Strategy, which lists “Safer Speeds” as one of five core objectives.13US Department of Transportation. National Roadway Safety Strategy Those are recommendations, though, not mandates. Since 1995, how fast you can drive has been a question for your state, not Washington.