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, 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 Congress repealed the NMSL in 1995, fully returning speed limit-setting authority to the individual states.but many jurisdictions discovered it to be a major source of revenue.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
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) to conserve gasoline and rubber for the American war effort. 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.
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 (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. 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).
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."
The Emergency Highway Energy Conservation Act 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.was a bill in the U.S. Congress that included the National Maximum Speed Limit. 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
The legislation required55 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.
A survey by the Associated Press found that, as of Wednesday, January 2, 1974:
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).
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.
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, mph (90 km/h) speed limit: Alaska, New Hampshire and Wyoming.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. 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
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. mph (90 km/h) speed limit in these areas.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: "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
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 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) while the full repeal in 1995 led to a further 15% increase in fatalities. 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.
In 1998, the Transportation Research Board footnoted an estimate that the 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.’s vehicle-miles-traveled in 1973, but such free-flowing roads typically provide more fuel-efficient travel than conventional roads.
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, by the 1980s traffic surveys showed the NMSL was widely violated:
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. A total of 40 states raised their speed limits to 65 mph on rural Interstate highway and non-Interstate rural roads built to Interstate standards by 1988, joined by Massachusetts (Turnpike only) in 1992, and by Maryland, New York and Pennsylvania in the summer of 1995.
The higher speed limit on most rural Interstates and similar non-Interstate roads was vehemently opposed by highway safety advocates, including the National Safety Council, Public Citizen, Mothers Against Drunk Driving, American Trucking Associations, and the Insurance Institute for Highway Safety, all ardent, long-time supporters of 55 mph (90 km/h). On the other hand, the new 65 mph speed limit for rural Interstates was welcomed by the California Highway Patrol, National Motorists Association (nee Citizens' Coalition for Rational Traffic Laws), a motorists' advocacy group, American Motorcyclist Association, Owner-Operator Independent Drivers Association (OOIDA), the automotive enthusiast magazines Motor Trend, Road & Track, Car and Driver, and the late automotive journalist Brock Yates (1934-2016)--perhaps the most outspoken published opponent of the 55 mph National Maximum Speed Limit.
Under the Intermodal Surface Transportation Efficiency Act of 1991, mph speed limit was made permanent for rural non-Interstate highways built to Interstate standards. It also declared a moratorium on Federal sanctions against states in noncompliance with the 55 mph (90 km/h) national speed limit for fiscal years 1990 and 1991, and directed the U.S. Department of Transportation to promulgate new compliance standards for the 65 mph rural freeways, as well as for all 55 mph (90 km/h) highways. As required by ISTEA, they were published in the Code of Federal Regulations 23 CFR Part 1260, but no further action was taken by USDOT against the states for speed limit noncompliance for the last few years the NMSL was still in effect until it was repealed in 1995.passed by Congress and signed by President George HW Bush on December 18, 1991, the 65
A few roads that were not Interstate Highways but had been built to Interstate standards were redesignated as Interstate Highways to qualify for the increased speed limit:
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 (89 km/h) in 1974 immediately reverted to 70 mph (110 km/h), causing some legal confusion before the new signs were posted. Montana reverted to non-numerical speed limits on most rural highways, but its legislature adopted 75 mph (121 km/h) as a limit in 1999; as a result, according to Insurance Institute for Highway Safety researcher Anne McCartt, "What's impressive is the huge drop in the percent of vehicles going very fast.... The proportion of vehicles exceeding 75 mph, the limit set [by Montana] in 1999, tumbled 45 percent. The proportion surpassing 80 mph plummeted 85 percent. Large trucks slowed, too." (She did not mention that the IIHS survey of traffic speeds on Interstate highways in 2006 she referred to, found Montana, as compared with New Mexico and Nevada, had the highest compliance with the 75 mph speed limit on rural interstates: 76 percent.) 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 (100 km/h).
Despite the repeal of federal speed limit controls, the 2011 maximum speed limits were on average lower than those of 1974:
Although traffic deaths and death rates have generally declined in the United States since 1989,highway safety advocates have long continued to assert that increases in state speed limits after the repeal of the National Maximum Speed Law have had a detrimental effect on highway safety, and they have conducted many studies including statistical analyses that claim to support this argument. For example, the Insurance Institute for Highway Safety declared that "each 5 mph increase in the maximum speed limit resulted in a 4 percent increase in fatalities. The increase on Interstates and freeways... was 8 percent. Comparing the annual number of fatalities in the 41 states [studied] with the number that would have been expected if each state's maximum speed limit had remained unchanged since 1993, [we] arrived at the estimate of 33,000 additional fatalities over the 20-year period [from 1993 to 2013]."
Effective September 1, 1979, in a FMVSS 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 (140 km/h). Some manufacturers circumvented the rule by including extra lines beyond 85 to show higher speeds. However, on March 25, 1982, NHTSA revoked that Standard (FMVSS 127) entirely, 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."
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 refers to the NMSL, and in jest, to the Sammy Hagar single. Films such as Smokey and the Bandit and The Cannonball Run were popular and humorous jabs at the NMSL.
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.". 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."
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, is a network of controlled-access highways that forms part of the National Highway System in the United States. Construction of the system was authorized by the Federal Aid Highway Act of 1956. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.
The Federal-Aid Highway Act of 1973 is legislation enacted by the United States Congress and signed into law on August 13, 1973, which provided funding for existing interstate and new urban and rural primary and secondary roads in the United States. It also funded a highway safety improvement program, and permitted states for the first time in U.S. history to use Highway Trust Fund money for mass transit. The law also established the first national speed limit.
Road speed limits are used in most countries to set the legal maximum, middle or minimum speed at which road vehicles may travel on a given stretch of road. Speed limits are generally indicated on a traffic sign reflecting the maximum, middle or minimum permitted expressed as kilometres per hour (km/h) and/or miles per hour (mph). Speed limits are commonly set by the legislative bodies of national or provincial governments and enforced by national or regional police and judicial authorities. Speed limits may also be variable, or in some places nonexistent, such as on most of the Autobahn in Germany.
The Kansas Turnpike is a 236-mile-long (380 km), freeway-standard toll road that lies entirely within the U.S. state of Kansas. It runs in a general southwest–northeast direction from the Oklahoma border to Kansas City. It passes through several major Kansas cities, including Wichita, Topeka, and Lawrence. The turnpike is owned and maintained by the Kansas Turnpike Authority (KTA), which is headquartered in Wichita.
The Autobahn is the federal controlled-access highway system in Germany. The official German term is Bundesautobahn, which translates as "federal motorway". The literal meaning of the word Bundesautobahn is "Federal Auto(mobile) Track".
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms include throughway and parkway. Some of these may be limited-access highways, although this term can also refer to a class of highway with somewhat less isolation from other traffic.
Speed limits in the United States are set by each state or territory. States have also allowed counties and municipalities to enact typically lower limits. Highway speed limits can range from an urban low of 25 mph (40 km/h) to a rural high of 85 mph (137 km/h). Speed limits are typically posted in increments of five miles per hour (8 km/h). Some states have lower limits for trucks and at night, and occasionally there are minimum speed limits.
Interstate 95 (I-95) in the US state of Maine is a 303-mile-long (488 km) highway running from the New Hampshire state line in Kittery, to the Canadian border in Houlton. It is the only two-digit Interstate Highway in Maine. In 2004, the highway's route between Portland and Gardiner was changed so that it encompasses the entire Maine Turnpike, a toll road running from Kittery to Augusta.
For driving in the United States, each state and territory has its own traffic code or rules of the road, although most of the rules of the road are similar for the purpose of uniformity, given that all states grant reciprocal driving privileges to each other's licensed drivers. There is also a "Uniform Vehicle Code" which was proposed by a private, non-profit group, based upon input by its members. The UVC was not adopted in its entirety by any state. As with uniform acts in general, some states adopted selected sections as written or with modifications, while others created their own sui generis statutes touching upon the same subject matter. As required by the federal Highway Safety Act of 1966, all states and territories have adopted substantially similar standards for the vast majority of signs, signals, and road surface markings, based upon the Manual on Uniform Traffic Control Devices from the U.S. Department of Transportation. Many of the standard rules of the road involve consistent interpretation of the standard signs, signals, and markings such as what to do when approaching a stop sign, or the driving requirements imposed by a double yellow line on the street or highway. Many agencies of the federal government have also adopted their own traffic codes for enforcement on the grounds of their respective facilities.
Transportation safety in the United States encompasses safety of transportation in the United States, including automobile crashes, airplane crashes, rail crashes, and other mass transit incidents, although the most fatalities are generated by road incidents.
Road speed limits in Ireland apply on all public roads in the state. These are signposted and legislated for in kilometres per hour. Speed limits are demarcated by regulatory road signs. These consist of white circular signs with a red outline. Speed limits are marked in black with "km/h" below the speed limit. Smaller "repeater" speed limit signs are used along stretches of road where there is no change in speed limit, in order to remind motorists currently on the road and to inform traffic merging from junctions that a certain speed limit applies.
Speed limits in Australia range from 5 kilometres per hour (3.1 mph) shared zones to 130 kilometres per hour (81 mph). In the Northern Territory four highways have 130 kilometres per hour (81 mph) zones. Speed limit signage is in km/h since metrication on 1 July 1974. All speed limits are multiples of 10 km/h – the last digit in all speed signs is zero. Speed limits are set by state and territory legislation albeit with co-ordination and discussion between governments.
Driving in the United States is a frequent occurrence, with the majority of Americans using private automobiles as their primary form of transportation to their workplace. Each state has the authority to set its own traffic laws and issue driving licenses, although these laws are largely the same and licenses from other states are respected throughout the country. Americans drive on the right side of the road. There are numerous regulations on driving behavior, including speed limits, passing regulations, and seat belt requirements. Driving while intoxicated with alcohol is illegal in all jurisdictions within the U.S.
A road speed limit is the limit of speed allowed by law for road vehicles, usually the maximum speed allowed. Occasionally, there is a minimum speed limit. Advisory speed limit also exist. Speed limits are commonly set by the legislative bodies of national or local governments.
Canadian speed limits are set by different levels of government, depending on the jurisdiction under which the road falls, resulting in differences from province to province. The limits have been posted in kilometres per hour (km/h) since September 1, 1977. Before then, when Canada used Imperial units, speed limits were in miles per hour (mph).
The Solomon curve is a graphical representation of the collision rate of automobiles as a function of their speed compared to the average vehicle speed on the same road. The curve was based on research conducted by David Solomon in the late 1950s and published in 1964. Subsequent research suggests significant biases in the Solomon study, which may cast doubt on its findings.
Speed limit enforcement is the effort made by appropriately empowered authorities to improve driver compliance with speed limits. Methods used include roadside speed traps set up and operated by the police and automated roadside 'speed camera' systems, which may incorporate the use of an automatic number plate recognition system. Traditionally, police officers used stopwatches to measure the time taken for a vehicle to cover a known distance. More recently, radar guns and automated in-vehicle systems have come into use.
Road speed limits in the United Kingdom are used to define the maximum legal speed for vehicles using public roads in the UK. Speed limits are one of the measures available to attempt to control traffic speeds, reduce negative environmental effects of traffic, increase fuel use efficiency and satisfy local community wishes. The speed limit in each location is indicated on a nearby traffic sign or by the presence of street lighting. Signs show speed limits in miles per hour (mph) or the national speed limit (NSL) sign may be used.
General speed limits in Germany are set by the federal government. All limits are multiples of 10 km/h. There are two default speed limits: 50 km/h (31 mph) inside built-up areas and 100 km/h (62 mph) outside built-up areas. While parts of the autobahns and many other freeway-style highways have posted limits up to 130 km/h (81 mph) based on accident experience, congestion and other factors, many rural sections have no general speed limit. The German Highway Code (Straßenverkehrsordnung) section on speed begins with the requirement which may be rendered in English:
Any person driving a vehicle may only drive so fast that the car is under control. Speeds must be adapted to the road, traffic, visibility and weather conditions as well as the personal skills and characteristics of the vehicle and load.
Speed limits in the United States vary depending on jurisdiction. Rural freeway speed limits of 70 to 80 mph are common in the Western United States, while such highways are typically posted at 65 or 70 mph in the Eastern United States. States may also set separate speed limits for trucks and night travel along with minimum speed limits. The highest speed limit in the country is 85 mph (137 km/h), which is posted on a single stretch of tollway in exurban areas outside Austin, Texas. The lowest maximum speed limit in the country is 30 miles per hour (48 km/h) in American Samoa.
Bloomquist (1984) estimated that the 1974 National Maximum Speed Limit (NMSL) reduced fuel consumption by 0.2 to 1.0 percent.Cite journal requires
|"Photograph of 55 mph speed limit replacing a 70 mph limit". February 12, 1974.|
|"Photograph of KSDOT workers changing a 75 mph sign to 55 mph". 1974. Archived from the original on December 23, 2016. Retrieved December 22, 2016.|