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The National Maximum Speed Law (NMSL) in the United States was a provision of the Federal 1974 Emergency Highway Energy Conservation Act that prohibited speed limits higher than 55 miles per hour (90 km/h). It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis.
Contents
- History
- 197355mph National Speed Limit
- Enactment
- Safety impact
- Fuel savings
- Opposition and noncompliance
- 1987 and 198865mph limit
- Reclassified roads
- 1995Repeal of federal limits
- Speedometers
- In popular culture
- References
While Federal officials hoped gasoline consumption would fall by 2.2%, actual savings were estimated at between 0.5% and 1%.
The law was widely disregarded by motorists, 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 Congress repealed the NMSL in 1995, fully returning speed limit setting authority to the states.
The law's safety benefit is disputed as research found conflicting results.
History
Historically, the power to set speed limits belonged to the states. Immediately before the National Maximum Speed Law became effective, speed limits were as high as 75 mph (120 km/h). (Kansas had lowered its turnpike speed limit from 80 before 1974.) Montana and Nevada generally posted no speed limits on highways, limiting drivers to only whatever was safe for conditions.
1973—55 mph National Speed Limit
As of November 20, 1973, several states had modified speed limits:
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 speed limit for trucks and buses. That, combined with a ban on ornamental lighting, no gasoline sales on Sunday, and a 15% cut in gasoline production, were proposed to reduce total gas consumption by 200,000 barrels a day, representing a 2.2% drop from annualized 1973 gasoline consumption levels. Nixon partly based this on a belief that cars achieve maximum efficiency between 40 and 50 mph (65 and 80 km/h) and that trucks and buses were most efficient at 55 mph (90 km/h).
The California Trucking Association, the then-largest trucking association in the United States, opposed differential speed limits on grounds that they are "not wise from a safety standpoint."
Enactment
The Emergency Highway Energy Conservation Act was a bill in the U.S. Congress that enacted the National Maximum Speed Law. 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 President Nixon on January 2, 1974, and became effective 60 days later, by requiring the limit as a condition of each state receiving highway funds, a use of the Commerce Clause of the United States Constitution.
The legislation required 55 mph (90 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 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 (90 km/h) on all other roads.
A survey by the Associated Press found that, as of Wednesday, January 2, 1974:
This 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 Robert Dole to raise the speed limit to 60 mph (95 km/h).
Safety impact
The limit's effect on highway safety is unclear. During the time the law was enacted and after it was repealed automobile fatalities decreased, and this was widely attributed mainly to automobile safety improvements, owing to an increase in the safety of cars themselves. This decrease in fatalities from automobile accidents makes figuring out the actual impact of the law difficult.
According to the National Research Council, there was a decrease in fatalities of about 4000 lives in the first year after the law took effect. 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 noted that on rural interstates, the free-flowing traffic speed should be the major determinant of the speed limit, because "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 speed laws in these areas.
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. After the oil crisis abated, the NMSL was retained mainly due to the possible safety aspect.
Insurance Institute for Highway Safety workers wrote three papers that argue that increase from 55 to 65 mph (90 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) while the full repeal in 1995 led to a further 15% increase in fatalities. In contrasting work, 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.
Fuel savings
In 1998, the U.S. Transportation Research Board footnoted an estimate that the 1974 National Maximum Speed Limit (NMSL) reduced fuel consumption by 0.2 to 1.0 percent. Rural interstates, the roads most visibly affected by the NMSL, accounted for 9.5% of the U.S' vehicle-miles-traveled in 1973, but such free-flowing roads typically provide more fuel-efficient travel than conventional roads.
Conservative think tank The Heritage Foundation claims that the United States Department of Transportation's Office of Driver Research found total fuel savings to be 1% and that "independent studies" found a 0.5% savings.
Opposition and noncompliance
By the 1980s, traffic surveys showed the NMSL was widely violated::
1987 and 1988—65 mph limit
In the April 2, 1987, Surface Transportation and Uniform Relocation Assistance Act, Congress permitted states to raise speed limits to 65 mph (105 km/h) on rural Interstate highways. In a bill that passed in mid-December 1987, Congress allowed certain non-Interstate rural roads built to Interstate standards to have the higher speed limits. As of December 29, 1987, the states of California, Florida, Illinois, Iowa, Kansas, Kentucky, and Oklahoma had applied for and been accepted into this program. The program was originally slated to last four years.
Reclassified roads
A few roads that weren't Interstate Highways but were built to Interstate standards were redesignated as Interstate Highways to qualify for the increased speed limit:
1995—Repeal of federal limits
Congress lifted all federal speed limit controls in the National Highway System Designation Act of 1995, returning all speed limit determination authority to the states effective December 8, 1995. Several states immediately reverted to already existing laws. For example, most Texas rural limits that were above 55 mph (90 km/h) in 1974 immediately reverted to 70 mph (115 km/h), causing some legal confusion before the new signs were posted. Montana reverted to non-numerical speed limits on most rural highways, although its legislature adopted 75 mph (120 km/h) as a limit in 1999. Hawaii was the last state to raise its speed limit when, in response to public outcry after an experiment with traffic enforcement cameras in 2002, it raised the maximum speed limit on parts of Interstates H-1 and H-3 to 60 mph (95 km/h).
Despite the repeal of federal speed limit controls, 2011 maximum speed limits were, on average, lower than in 1974:
Speedometers
On October 1, 1980, in a regulation that also regulated speedometer and odometer accuracy, the National Highway Traffic Safety Administration (NHTSA) required speedometers to have special emphasis on the number 55 and a maximum speed of 85 mph (137 km/h). However, on October 19, 1980, NHTSA proposed eliminating speedometer and odometer rules because they were "unlikely to yield significant safety benefits" and "[a] highlighted '55' on a speedometer scale adds little to the information provided to the driver by a roadside speed limit sign."
In popular culture
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". 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 also refers to it.
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." Intelligentsia riffed that 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."