National Maximum Speed Law
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). The limit was increased to 65 miles per hour (105 km/h) in 1987. It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis. Even after fuel costs began to decrease over time the law would remain in place until 1995 as proponents claimed it reduced traffic fatalities.[1][2]
"Double nickel" redirects here. For the Interstate Highway in the central United States nicknamed "double nickel", see Interstate 55.
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,[3][4] 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 Congress repealed the NMSL in 1995, fully returning speed limit-setting authority to the individual states.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.[5][6] Immediately before the NMSL became effective, speed limits were as high as 75 mph (121 km/h).[7] (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.
As of November 20, 1973, several states had modified speed limits:[8]
As an emergency response to the 1973 oil crisis, on November 26, 1973, President Richard Nixon proposed a national 50 mph (80 km/h) speed limit for passenger vehicles and a 55 mph (90 km/h) speed limit for trucks and buses. Also proposed were a ban on ornamental lighting, no gasoline sales on Sunday, and a 15% cut in gasoline production to reduce total gas consumption by 200,000 barrels a day, representing a 2.2% drop from annualized 1973 gasoline consumption levels.[12][a] Nixon partly based that on a belief that cars achieve maximum efficiency between 40 and 50 mph (64 and 80 km/h) and that trucks and buses were most efficient at 55 mph (89 km/h).[14]
The California Trucking Association, the largest trucking association in the United States, opposed differential speed limits on grounds that they are "not wise from a safety standpoint."[15]
The Emergency Highway Energy Conservation Act[16] was a bill in the U.S. Congress that included the National Maximum Speed Limit.[17] States had to agree to the limit if they desired to receive federal funding for highway repair. The uniform speed limit was signed into law by Nixon on January 2, 1974, and became effective 60 days later,[18] by requiring the limit as a condition of each state receiving highway funds, a use of the Commerce Clause of the United States Constitution.[19]
The legislation required 55 mph (89 km/h) speed limits on all four-lane divided highways unless the road had a lower limit before November 1, 1973. In some cases, like the New York State Thruway, the 50 mph (80 km/h) speed limit had to be raised to comply with the law. The law capped speed limits at 55 mph (89 km/h) on all other roads.[18]
A survey by the Associated Press found that, as of Wednesday, January 2, 1974:[18]
That includes some states that voluntarily lowered their limits in advance of the federal requirement.
On May 12, 1974, the United States Senate defeated a proposal by Senator Bob Dole to raise the speed limit to 60 mph (97 km/h).[20]
The 55 mph (90 km/h) National Maximum Speed Limit was made permanent when Congress enacted and President Gerald Ford signed into law the Federal-Aid Highway Amendments of 1974 on January 4, 1975.[21]
Safety impact[edit]
The limit's effect on highway safety is unclear. Both during the time the law was enacted and after it was repealed, automobile fatalities decreased,[22] which was widely attributed mainly to automobile safety improvements, owing to an increase in the safety of cars themselves, and the passage of mandatory seat belt legislation by all states except New Hampshire from the mid-1980s to the early 1990s.[23][24] This decrease in fatalities from automobile accidents makes figuring out the actual impact of the law difficult. Although the vast majority of states reported fewer traffic deaths in 1974 compared with 1973, there were in fact three states where traffic deaths actually increased in 1974, 1975 and 1976, compared to 1973, notwithstanding the 55 mph (90 km/h) speed limit: Alaska, New Hampshire and Wyoming.
[25]
According to the National Research Council, there was a decrease in fatalities of about 3,000 to 5,000 lives in 1974, and about 2,000 to 4,000 lives saved annually thereafter through 1983 because of slower and more uniform traffic speeds since the law took effect.[26] Later, the National Academies wrote that there is "a strong link between vehicle speed and crash severity [which] supports the need for setting maximum limits on high-speed roads" but that "the available data do not provide an adequate basis for precisely quantifying the effects that changes in speed limits have on driving speeds, safety, and travel time on different kinds of roads." The Academies report also observed that on rural interstates, the free-flowing traffic speed should be the major determinant of the speed limit: "Drivers typically can anticipate appropriate driving speeds." This is due, in part, to the strong access control in these areas but also is an acknowledgement of the difficulty of enforcing the 55 mph (90 km/h) speed limit in these areas.[27]
A Cato Institute report showed that the safety record worsened in the first few months of the new speed limits, suggesting that the fatality drop found by the NRC was a statistical anomaly that regressed to the mean by 1978.[28] After the oil crisis abated, the NMSL was retained mainly due to the possible safety aspect.[29]
Insurance Institute for Highway Safety analysts wrote three papers that argue that increase from 55 to 65 mph (89 to 105 km/h) on rural roads led to a 25% to 30% increase in deaths (1/3 from increased travel, 2/3 from increased speed)[30] while the full repeal in 1995 led to a further 15% increase in fatalities.[30] In contrast, researchers at University of California Transportation Science Center argue that the interstates in question are only part of the equation, one also must account for traffic moving off the relatively more dangerous country roads and onto the relatively safer interstates. Accounting for this they find that raising rural speed limits to 65 mph (105 km/h) caused a 3.4% to 5.1% decrease in fatalities.[31]
Fuel savings[edit]
In 1998, the Transportation Research Board footnoted an estimate that the NMSL reduced fuel consumption by 0.2 to 1.0 percent.[32] Rural interstates, the roads most visibly affected by the NMSL, accounted for 10% of the U.S.'s vehicle-miles-traveled in 1973,[33] and although dropping speeds from 75 to 55 mph (120 to 90 km/h) reduces air resistance by over half, such free-flowing roads typically provide more fuel-efficient travel than conventional roads.[34][35][36]
Despite federal compliance standards mandated by Congress that no more than 50 percent of free-flowing traffic on 55 mph-posted highways exceed 55 mph from 1981 onwards, which required up to a 10 percent reduction in federal highway funding for states in noncompliance,[37] by the 1980s traffic surveys showed the NMSL was widely violated:
In popular culture[edit]
The number 55 became a popular shorthand for the 55 mph speed limit. For example, a hand with a pair of fives in Texas hold'em poker is referred to as a "speed limit".[70] Rock musician Sammy Hagar released "I Can't Drive 55", a hit single protesting the rule. The title of Minutemen's critically acclaimed double album Double Nickels on the Dime refers to the NMSL, and in jest, to the Sammy Hagar single. The bill limiting speed limits was used as a debate topic in Season 2 Episode 12 of The Simpsons.
One of a series of advertising campaigns for the 55 mph speed limit offered, "Speed limit 55. It's not just a good idea. It's the law.".[71][72][73] This was parodied with a more absolute statement based on the speed of light: "186,000 miles per second. It's not just a good idea, it's the law."[74]