Speed limits in the United States are set by each state or territory. Highway speed limits can range from an urban low of 35 mph (56 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. Most speed limits are set by state or local statute, although each state allows various subdivisions (counties and municipalities) to set a different, generally lower, limit.
The highest speed limits are generally 70 mph (113 km/h) on the West Coast and the inland eastern states, 75-80 mph (121-129 km/h) in inland western states, along with Louisiana, and 65-75 mph (105-121 km/h) on the Eastern Seaboard. Alaska, Puerto Rico, and Vermont (the only inland northeastern state), have a maximum limit of no higher than 65 mph (105 km/h), and Hawaii has a maximum limit of 60 mph (97 km/h). Washington, D.C. and the U.S. Virgin Islands have a maximum speed limit of 55 mph (89 km/h), and Guam and the Samoa have speed limits of 45 mph (72 km/h). Unusual for a state east of the Mississippi, much of I-95 in Maine north of Bangor allows up to 75 mph (121 km/h). Although Nevada law has allowed speed limits up to 80 mph (129 km/h) since October 2015, no 80 mph (129 km/h) limit had been posted in Nevada as of August 2016, and it stays pending. Portions of the Idaho, Montana, South Dakota, Texas, Utah, and Wyoming road networks have 80 mph (129 km/h) posted limits. The highest posted speed limit in the entire country can be found in one single stretch of rural freeway in Texas, and it is 85 mph (137 km/h).
For 13 years (January 1974-April 1987), federal law prohibited speed limits above 55 mph (89 km/h). From April 1987 through December 8, 1995, an amended federal law prohibited speed limits above 65 mph (105 km/h).
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Speed limits
This table contains the most usual posted daytime speed limits, in miles per hour, on typical roads in each category. The values shown are not necessarily the fastest or slowest. They usually indicate, but not always, statutory speed limits. Some states and territories have lower truck speed limits applicable to heavy trucks. If present, they are usually only on freeways or other high-speed roadways. Nevada and Washington allow for speeds up to 80 and 75 mph respectively, but the highest posted signs are 75 and 70 mph respectively. Oklahoma removed the maximum speed of 75 from its laws, though no road been posted higher than 75.
History
One of the first speed limits in what would become the United States (at the time, still a British colony) was set in Boston in 1701 by the board of selectmen (similar to a city council):
Ordered, That no person whatsoever Shall at any time hereafter ride or drive a gallop or other extream pace within any of the Streets, lanes, or alleys in this Town on penalty of forfeiting three Shillings for every such offence, and it may be lawfull for any of the Inhabitants of this Town to make Stop of such horse or Rider untill the name of the offender be known in order to prosecution
Federal speed controls
In response to the 1973 oil crisis, Congress enacted the National Maximum Speed Law that created the universal 55 miles per hour (89 km/h) speed limit. Whether this reduced gasoline consumption is debated and the impact on safety is unclear; studies and opinions of safety advocates are mixed.
The law was widely disregarded by motorists, even after the national maximum was increased to 65 miles per hour (105 km/h) on certain roads in 1987 and 1988. In 1995, the law was repealed, returning the choice of speed limit to each state.
Minimum speed limits
In addition to the legally defined maximum speed, minimum speed limits may be applicable. Occasionally, there are default minimum speed limits for certain types of roads, generally freeways.
Comparable to the common basic speed rule, most jurisdictions also have laws prohibiting speeds so low they are dangerous or impede the normal and reasonable flow of traffic.
Truck speed limits
Some jurisdictions set lower speed limits that are applicable only to large commercial vehicles like heavy trucks and buses. While they are called "truck speed limits", they generally do not apply to light trucks.
Theory
The research record is mixed. A 1987 study finds that crash involvement significantly increases when trucks drive much slower than passenger vehicles, suggesting that the difference in speed between passenger vehicles and slower trucks could cause crashes that otherwise may not happen. Furthermore, in a review of available research, the Transportation Research Board (part of the United States National Research Council) states "[no] conclusive evidence could be found to support or reject the use of differential speed limits for passenger cars and heavy trucks" (page 11) and "a strong case cannot be made on empirical grounds in support of or in opposition to differential speed limits" (page 109).
One study has claimed that two thirds (67%) of truck/passenger car crashes are the fault of the passenger vehicle.
Night speed limits
The basic speed rule requires drivers adjust speeds to the conditions. This is usually relied upon to regulate proper night speed reductions, if required. Numeric night speed limits, which generally begin 30 minutes after sunset and end 30 minutes before sunrise, are occasionally used where, in theory, safety problems require a speed lower than what is self-selected by drivers.
Examples include:
- Some streets in Tucson, Arizona without street lights.
- Some Florida roads near Southwest Florida International Airport near Cape Coral/Fort Myers. (Most of these roads are labeled as "Panther Zones" or "Panther X-ing" areas.)
- Daniels Parkway Ext., a four-lane divided highway near SW Florida International Airport with 50 mph daytime limit, and a night speed limit of 45 mph is considered by many to be a speed trap. This road joins neighboring SR 82, a two-lane road with a 60 mph speed limit.
- Colorado Highway 13, with a 65 mph day/55 mph night speed limit beginning 7.1 miles north of I-70 from north of Rifle to Colorado Highway 64 south of Meeker. Rural Colorado Highway 13 is 55 mph at night north of Meeker all the way to the Wyoming state line.
Some states create arbitrary night speed limits applicable to entire classes of roads. Until September 2011, Texas had a statutory 65 mph night speed limit for all roads with a higher limit. Montana has a statutory 65 mph night speed limit on all federal, state, and secondary roads except for Interstates.
Political considerations
Inconsistency
Subjective or political influence on speed limits is evident by state-to-state speed limit variances that have no empirical justification. Highlighted examples include:
- All 51 miles (82 km) of I-95 in Pennsylvania are posted at 55 mph (89 km/h), while in neighboring New Jersey, the speed limit on I-95 is primarily 65 mph (105 km/h), despite their common suburban environment.
- Cars and trucks traveling on US Route 30 from Indiana to Ohio can increase their speeds from 60 mph to 70 mph while cars and trucks traveling on the same roadway westbound from Ohio into Indiana will need to drop their speeds from 70 mph to 60 mph despite similar scenery and road configurations.
- Ohio has no separate truck speed limit on its interstates, but Michigan on the other hand has a 10 mph reduction for trucks. (If the speed limit for cars is 70, then the truck speed limit is 60). Interstate 75 in Ohio just south of the Michigan state line has a uniform 65 mph limit. Thus, cars traveling north on I-75 into Michigan are allowed to speed up by 5 mph, but trucks actually have to do the exact opposite and slow down by 5 mph on the same roadway.
- The following states as of May, 2016 allow 70 mph and higher speed limits on non freeway roads: Idaho, Kansas, Missouri, Montana, Nevada, New Mexico, North Dakota, Oklahoma, Ohio, Oregon, South Dakota, Texas, Washington, and Wyoming.
- Only 3 of the mentioned states above have a speed limit of 75 in their non-freeways: New Mexico (On U.S. Route 70), Nevada (On U.S. Route 95), and many roads in Texas.
- The lowest class of state-maintained, two-lane road in Texas may have a 75 mph speed limit, but a two-lane US highway built to neighboring Arkansas's or Louisiana's highest standards may not have a speed limit over 55, whereas a state road crossing through New Mexico and Oklahoma 's highest standards as a two-lane road is reduced to 65 mph.
- Several roads in Minnesota and Missouri such as U.S. Routes 75, 59, and 71 have 60 mph limits while Iowa has only 55 mph limits for the same roads.
- Trucks traveling westbound on I-10 or I-40 from Arizona (which has no separate truck speed limit) into California see their legal speed limit drop from 75 mph to 55 mph, despite similar road conditions.
- Only 6 states allow two-lane highways to be posted at 70 mph or higher: Idaho, Montana, Nevada, Oregon (on US Route 95), Texas and Wyoming. *(Texas as of 2015 allows 70 - 75 mph limits on some two lanes, mainly rural roads)
- The following states allow urban freeways to have speed limits of 70 mph or higher: Florida, Georgia, Illinois, Indiana, Michigan, Missouri, New Mexico, Oklahoma, South Carolina, Texas, and Utah.
- From 1995-1999 Montana set a daytime non-absolute speed limit of "Reasonable and Prudent". The Montana Supreme Court overturned the speed limit in December 1998 ruling the speed limit as too vague to enforce.
Even in-state examples point to inconsistencies. For example, I-10 and I-20 in far west Texas have had the following speed limits despite no significant changes in roadway characteristics:
- Before 1963: 60 mph day/55 mph night
- 1963-1974: 70 mph day/65 mph night
- 1974-1986: 55 mph (National Maximum Speed Law)
- 1986-1995: 65 mph (NMSL 65 mph amendment)
- 1995-2001: 70 mph day/65 mph night
- 2001-2006: 75 mph day/65 mph night
- 2006-2012: 80 mph day/65 mph night
- 2012-: 80 mph
Financial concerns
Traffic violations can be a lucrative income source for jurisdictions and insurance companies. For example:
- Westlake, TX took in $42,000 per citizen over nine years for its speed traps.
- Insurance companies may receive several billions of dollars annually in traffic ticket surcharges.
- A study by the Federal Reserve of St. Louis found that traffic ticket writing increases when government revenue decreases.
- 2008 debates over traffic enforcement in Dallas County, TX involved concerns of lost profits if ticketwriting decreased.
- In Massachusetts, half of the ticket money goes to the police department that writes the speeding ticket, the other half goes to fund the court that convicts the speeder or collects the fine from them.
Thus, an authority that sets and enforces speed limits, such as a state government, regulates and taxes insurance companies, who also gain revenue from speeding enforcement. Furthermore, such an authority often requires "all" drivers to have policies with those same companies, solidifying the association between the state and auto insurers. If a driver cannot be covered under an insurance policy because of high risk, the state will assume that high risk for a greater monetary amount; thus resulting in even more revenue generation for the state.
When a speed limit is used to generate revenue but has no safety justification, it is called a speed trap. The town of New Rome, Ohio was such a speed trap, where speeding tickets raised up to $400,000 per year to fund the police department of a 12-acre village with 60 residents.
Environmental concerns
Reduced speed limits are sometimes enacted for air quality reasons. The most prominent example includes Texas' environmental speed limits.
Metric speed limits
Though not common in the United States, a speed limit may be defined in kilometers per hour (km/h) as well as miles per hour (mph). The Federal Highway Administration's Manual on Uniform Traffic Control Devices, which provides guidelines for speed limit signage, states that "speed limits shown shall be in multiples of 10 km/h or 5 mph." If a speed limit sign indicates km/h, the number is circumscribed and "km/h" is written below. Prior to 2003, metric speed limits were designated using the standard speed limit sign, usually with yellow supplemental "METRIC" and "km/h" plaques above it and below it, respectively.
In 1995, the National Highway System Designation Act prohibited use of federal funds to finance new metric signage.
Definition of speeding
Either of the following qualifies a crash as speed-related in accordance with U.S. government rules:
- Exceeding speed limits.
- Driving too fast for conditions.
Speeds in excess of speed limits account for most speed-related traffic citations; generally, "driving too fast for conditions" tickets are issued only after an incident where the ticket issuer found tangible evidence of unreasonable speed, such as a crash.
A criticism of the "exceeding speed limits" definition of speeding is twofold:
- When speed limits are arbitrary, such as when set through political rather than empirical processes, the speed limit's relationship to the maximum safe speed is weakened or intentionally eliminated. Therefore, a crash can be counted as speed-related even if it occurs at a safe speed, simply because the speed was in excess of a politically determined limit.
- The effective limit may still be too fast for certain conditions, such as limited visibility or reduced road traction or even low-speed truck rollovers on exit ramps.
Variable speed limits offer some potential to reduce speed-related crashes. However, due to the high cost of implementation, they exist primarily on freeways. Furthermore, most speed-related crashes occur on local and collector roads, which generally have far lower speed limits and prevailing speeds than freeways.
Prima facie
Most states have absolute speed limits, meaning that a speed in excess of the limit is illegal per se. However, some states have prima facie speed limits. This allows motorists to defend against a speeding charge if it can be proven that the speed was in fact reasonable and prudent.
Speed limits in Texas, Utah, and Rhode Island are prima facie. Some other states have a hybrid system: speed limits may be prima facie up to a certain speed or only on certain roads. For example, speed limits in California up to 55 mph, or 65 mph on highways, are prima facie, and those at or above those speeds are absolute.
A successful prima facie defense is rare. Not only does the burden of proof rest upon the accused, a successful defense may involve expenses well in excess of the cost of a ticket, such as an expert witness. Furthermore, because prima facie defenses must be presented in a court, such a defense is difficult for out-of-town motorists.
Source of the article : Wikipedia
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