Speed limit

A typical 60 km/h speed limit sign used in Australia
A typical speed limit sign in the United States showing a 50 mph restriction.

Road speed limits are used in most countries to regulate the speed of road vehicles. Speed limits may define maximum (which may be variable), minimum or no speed limit and are normally indicated using a traffic sign. Speed limits are commonly set by the legislative bodies of nations or provincial governments and enforced by national or regional police and / or judicial bodies.

The first maximum speed limit was the 10 mph (16 km/h) limit introduced in the United Kingdom in 1861. The Isle of Man[1] and some of the less congested Autobahns or roads with more than one lane for each direction in Germany[2] are the only places in the world that do not have a general speed limit.

Speed limits are usually set to attempt to cap road traffic speed; there are several reasons for wanting to do this. It is often done with an intention to improve road traffic safety and reduce the number of road traffic casualties from traffic collisions. In their World report on road traffic injury prevention report, the World Health Organization (WHO) identify speed control as one of various interventions likely to contribute to a reduction in road casualties. (The WHO estimated that some 1.2 million people were killed and 50 million injured on the roads around the world in 2004.)[n 1] Speed limits may also be set in an attempt to reduce the environmental impact of road traffic (vehicle noise, vibration, emissions), to reduce fuel use and to satisfy local community wishes.

Speed limits are used to reduce the differences in vehicle speeds by drivers using the same road at the same time which increases safety. In situations where the natural road speed is considered too high, notably on urban areas where speed limits below 50 km/h (31 mph) are used then traffic calming is often also used. For some classes of vehicle speed limiters may be mandated to enforce compliance.

Since they have been introduced speed limits have been opposed from various sources; including motoring advocacy groups, anti-motoring groups and others who either consider them to be irrelevant, set too low or set too high.

Contents

History

Antique New Hampshire speed limit sign.

The first speed limit legislation was created in the United Kingdom with the Locomotive Acts. The 1861 Act introduced a UK speed limit of 10 mph (16 km/h) (automobiles were in those days termed “light locomotives”) which was then reduced to 4 mph (6 km/h) in the country and 2 mph (3 km/h) in towns by the 1865 Act (the 'red flag act'). The first person to be convicted of speeding is believed to be Walter Arnold of East Peckham, Kent, who on 28 January 1896 was fined for speeding at 8 mph (13 km/h). He was fined 1 shilling plus costs.[3][4][5] The speed limit was raised to 30 mph (48 km/h) in 1903. All UK speed limits were removed by the Road Traffic Act 1930 only to have 30 mph (48 km/h) limit for urban areas introduced by the Road Traffic Act 1934.[6] A UK speed limit on all previously unrestricted roads (including motorways) of 70 mph (113 km/h) was introduced in 1965.[n 2]

Regulations

Speed limit sign common to much of Europe, showing a 60 km/h restriction. Similar signs in the UK are in mph.
Automobile speed limits on European freeways in km/h.

The vast majority of countries use metric units (kilometres per hour). The only countries using miles per hour are the United States and the United Kingdom. For a period of time California and Arizona used showed both metric and mph. At locations where drivers switch from one system to the other and near ports and airports signs may give speeds using both units.

Maximum speed limits

Most public roads in most countries have a legally assigned a numerical maximum speed limit which apply on all roads unless otherwise stated; lower speed limits are often shown on a sign at the start of the restricted section although the presence of streetlights, or the physical arrangement of the road may sometimes also be used instead. A posted speed limit may only apply to that road or to all roads beyond the sign that defines them depending on local laws. In the European Union, large signposts showing the national (default) speed limits of the respective country are usually erected immediately after border crossings, with a repeater sign some 200 to 500 m (660 to 1,600 ft) after the first sign. Some places provide an additional "speed zone ahead" ahead of the restriction and speed limit reminder signs may appear at regular intervals which may be painted on the road surface.

Signs are normally placed on both sides of the road and in some places there are small (less than 1/4 the size of the sign) rectangular orange reflector flags attached to both upper right corners of both signs. The speed limit sign marking the new speed zone may also have the orange flags.

Signage in many countries, especially in Europe conforms to the Vienna Convention on Road Signs and Signals using black text with a red circle on a white background. In the U.S., the signs are usually rectangular with the words "SPEED LIMIT" (in Canada, "MAXIMUM") and the values in black on a white background. The U.S. Federal Highway Administration's Manual on Uniform Traffic Control Devices provides guidelines for the appearance of speed limit signs. Australian signs are rectangular but have a red circle like the conventional signs.[7]

Posted maximum speeds are normally based on ideal driving conditions. Drivers are also required to not exceed a safe speed for the conditions, a requirement referred to in the United States as the basic rule [8], but more generally in Britain and elsewhere in common law as the reasonable man requirement.[9] Lower speed may be required due to fog, heavy rain, freezing conditions or where they are not able to stop in the line of sight. California Vehicle Code section 22350 is typical; it states that "No person shall drive a vehicle upon a highway at a speed greater than is reasonable... and in no event at a speed which endangers the safety of persons or property".[10] .

Minimum speed limits

Some roads also have "minimum speed limits", where slow speeds can impede traffic flow or be dangerous and on motorways slower vehicles such as horse drawn vehicles, bicycles and mopeds can be banned, e.g. in the United Kingdom.

Signs often use a blue circles based on the obligatory signs of the Vienna Convention on Road Signs and Signals. A Japanese minimum speed sign has the same design as a maximum speed sign but with a horizontal line below the number. In the United States of America, they are also identical to their respective maximum speed limit signs with the exception of the text "MINIMUM SPEED".

Variable speed limits

Example variable speed limit sign in the United States.

In Germany, the first experiments with variable signs took place in 1965 on A8 Munich-Salzburg with signs that were operated manually.

Beginning in the 1970s, more and more advanced Streckenbeeinflussungsanlagen (route control systems) were put into service. Modern motorway control systems can work without human intervention using various types of sensors to measure traffic flow and weather conditions. By 2007, 1,200 km (750 mi) (10%) of German motorways will be equipped with such systems.

A variable speed limit was introduced on part of Britain's M25 motorway in 1995 (on the busiest 14-mile (23 km) section from junction 10 to 16. Initial results suggested savings in journey times, smoother-flowing traffic, as well as a fall in the number of crashes and the scheme was made permanent in 1997.[11] However a 2004 National Audit Organization report noted that the business case was unproved; conditions at the site of the Variable Speed Limits trial were not stable before or during the trial, and the study was deemed neither properly controlled nor reliable.

New Zealand has had variable speed limits since 2001. The first installation was on the Ngauranga Gorge, a steep section of dual carriageway on State Highway 1 north of the capital, Wellington. The speed limit is normally 80 km/h.

From December 2008 the upgraded section of the M1 between the M25 and Luton will have the facility for variable speed limits.[12] In January 2010 temporary variable speed cameras on the M1 between J25 and J28 were made permanent.[13]

In Catalonia, the Generalitat Autonomous Government began applying variable speed limits in the Barcelona metropolitan area in March 2009.

In The Netherlands, much of the dense motorway network is equipped with variable speed regulation systems. The electronic signage is commonly posted every 500 m (1,640 ft). The system keeps track of all traffic movement and lowers the speed limit if it detects the start of traffic congestion. When activated the speed limit can be set at 90 km/h (56 mph), 70 km/h (43 mph), or 50 km/h (31 mph) according to the level of expected traffic congestion.

Variable speed limits are used on some stretches of highway in the United States. This has not, however, been implemented on a national basis. On Interstate 90 at Snoqualmie Pass, Washington, (near Seattle) variable speed limits are used to slow traffic in severe winter weather. This is also done on other mountain passes in Washington.[14] Variable speed limit signs, in combination with variable message signs, have been in use since the 1960s on the New Jersey Turnpike, where officials can adjust the speed limit according to weather, traffic conditions, and construction. Other roadways with variable speed limits include the Pulaski Skyway in New Jersey, I-495 in Delaware, and the Missouri part of the I-270/I-255 loop around St. Louis.

Roads without speed limits

German border crossing sign showing 50 km/h limit in built-up areas, 100 km/h in rural areas, but only an advisory 130 km/h limit for the Autobahn

For three years prior to 1999 Montana in the United States did not define a fixed upper speed limit in rural areas, beyond the Basic Rule[8] that "A person . . . shall drive the vehicle . . . at a rate of speed no greater than is reasonable and proper under the conditions existing at the point of operation . . . so as not to unduly or unreasonably endanger the life, limb, property, or other rights of a person entitled to the use of the street or highway."[1] A 75 mph limit was imposed in 1999 after a judge ruled that the definition was too vague and therefore violated the due process requirement of the Montana Constitution.[15]

Australia's Northern Territory had no blanket speed limits outside major towns until January 2007 when rural speed limits of 110 km/h or 130 km/h were introduced.[16] Prior to the speed limit fatalities were 55 (in 2005) and 44 (in 2006). In 2007 they rose to 57 and then again to 75 (in 2008) before falling to 31 in 2009.[17] The per-capita fatality rate in 2006 was the highest in the OECD and twice the Australian average.[18] In 2007 groups opposed to the speed limit said that it had failed and that the speed limit should be removed and that it was an "attack on our way of life".[19]

The Isle of Man has no speed limit on many rural roads; a 2004 proposal to introduce a general speed limits 60 mph and of 70 mph on Mountain Road for safety reasons were not progressed following consultation. [1] Measured travel speeds on the island are relatively low.[20]

Two-thirds of German autobahns have only advisory limits (Richtgeschwindigkeit). The length of speed-unrestricted autobahns slowly expanded after the opening of the East German borders in November 1989. Prior to German reunification in 1990, accident reduction programs in eastern German states were primarily focused on restrictive traffic regulation. Within two years after the opening, motorized traffic increased by 54% and annual traffic deaths doubled, despite "interim arrangements [which] involved the continuation of the speed limit of 100 km/h (62 mph) on autobahns and of 80 km/h (50 mph) outside cities and a blood alcohol limit of 0.0‰". An extensive program of the four Es (enforcement, education, engineering, and emergency response) brought the number of traffic deaths back to pre-unification levels after ten years while traffic regulations were raised to western standards (e.g., 130 km/h (81 mph) freeway advisory limit, 100 km/h (62 mph) on other rural roads, and 0.5 milligrams BAC). [21]

Enforcement

Gatso speed camera

Speed limit enforcement is the action taken by appropriately empowered authorities to check that road vehicles are complying with the speed limit. 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.

Effectiveness

The Synthesis of Safety Research Related to Speed and Speed Limits report sponsored by the Federal Highway Administration published in 1998 found that changing speed limits on low and moderate speed roads appeared to have no significant effect on traffic speed or the number of crashes, whilst on high-speed roads such as freeways, increased speed limits generally resulted in higher traffic speeds and more crashes. It is also stated that there is limited evidence to suggest that speed limits have a positive effect on a system wide basis.[n 3] Similar experiences have been noted when speed limits have been reduced, suggesting that it is the change of speed limits that causes more attentive driving for a period of time. However, after one year at the new speed limit, whether increased or decreased, the incidence of collisions and injuries returns to approximately the level it was before the change in the limit.

The speed limit is commonly set at or below the '85th percentile speed' (which is the speed at which 85% of the traffic is travelling)[22] and in the USA is typically set 8 to 12 mph (13 to 19 km/h) below that speed.[23]

A 2003 review of speed limits for British Columbia (Canada) identified a number of places where speed limits had been increased and decreased in various countries and the observed changes in speeding, fatalities, injuries and property damage which followed these changes:[n 4]

Results from lowering speed limits.[n 4]
Country Speed limit reduction Reported change
Australia 110 km/h to 100 km/h Injury crashes declined by 19%
Australia 5–20 km/h decreases No significant change
Denmark 60 km/h to 50 km/h Fatal crashes declined by 24%
Injury crashes declined by 9%
Germany 60 km/h to 50 km/h Crashes declined by 20%
Sweden 110 km/h to 90 km/h Speeds declined by 14 km/h
Fatal crashes declined by 21%
Switzerland 130 km/h to 120 km/h Speeds declined by 5 km/h
Fatal crashes declined by 12%
UK 100 km/h to 80 km/h Speeds declined by 4 km/h
Crashes declined by 14%
USA (22 states) 8–32 km/h decreases No significant changes
USA (Montana) Unlimited to 120 km/h Statewide fatality rates doubled
Results from increasing speed limits:[n 4]
Country Speed limit increase Reported change
Australia 100 km/h to 110 km/h Injury crashes increased by 25%
Australia (Victoria) 5–20 km/h increases Crashes increased overall by 8% 35% decline in zones raised from 60–80 km/h
USA 89 km/h to 105 km/h Fatal crashes increased by 21%
USA 89 km/h to 105 km/h Fatal crashes increased by 22%
Speeding increased by 48%
USA (40 states) 89 km/h to 105 km/h Fatalities increased by 15%
Decrease or no effect in 12 States
USA (Michigan) 89 km/h to 105 km/h Fatal and injury crashes increased significantly on rural freeways
USA (Ohio) 89 km/h to 105 km/h Injury and property damage increased but not fatalities after the increase in 1987.

[24]
USA (Indiana) 105 km/h to 110 km/h "the increased speed limit (in 2005[25] )did not affect the probability of suffering a severe injury in an accident"

[26]
USA (Utah) 125 km/h to 130 km/h "accidents and illegal speeding haven't increased"

[27]
USA (40 states) 89 km/h to 105 km/h Statewide fatality rates decreased 3-5% (Significant in 14 of 40 states)
USA (Montana) 105 km/h to Reasonable and Prudent Statewide fatality rates decreased 10%

By contrast to the above a survey of speeds on South Dakota Interstate roads in 2008 showed that 47% of drivers were driving over the 75 mph (120 km/h) speed limit, which is below observed 85th percentile speeds of 79-81 mph".[28]

The Synthesis of Safety Research Related to Speed and Speed Limits report sponsored by the Federal Highway Administration published in 1998 found that increasing speed limits on freeways and high-speed roads increased speed and crashes.[n 5]

Research in 1998 showed that the reduction of some 30 mph (48 km/h) United Kingdom speed limits to 20 mph (32 km/h) had achieved only a 1 mph drop in speeds and no discernible reduction in accidents; '20 mph speed limit zones' which use self enforcing traffic calming achieved average speed reductions of 10 mph, child pedestrian accidents were reduced by 70% and child cyclist accidents by 48%.[29]

Studies undertaken in conjunction with Australia's move from 60 km/h (37 mph) speed limits to 50 km/h (31 mph) in built-up areas and found that the measure was effective in reducing both speed and the frequency and severity of crashes.[30]

A study of the impact of the replacement of 60 km/h (37 mph) with 50 km/h (31 mph) speed limits in New South Wales, Australia showed only a 0.5 km/h drop in urban areas and a 0.7 km/h drop in rural areas. The report noted that widespread community compliance would require a combination of strategies including traffic calming treatments.[31]

Information campaigns are also used by authorities to support speed limits, for example the Speeding. No one thinks big of you. campaign in Australia 2007.

Justification

Speed limits are set primarily to balance road traffic safety concerns with the effect on travel time and mobility; more recently some administrations have suggested that the "balance" between safety and mobility should be judged from an ethical standpoint and that an upper speed limit should be set that would virtually eliminate the chance of a fatality occurring. Speed limits are also sometimes used to reduce consumption of fuel or in response to environmental concerns.[32]

Road traffic safety

The Pan-American Highway with central median and no freestanding obstructions increasing level of safety at high speed
Traffic calming can be effective on lower speed roads

According to a 2004 report from the World Health Organisation a total of 22% of all 'injury mortality' worldwide were from road traffic injuries in 2002[n 6] and without 'increased efforts and new initiatives' casualty rates would increase by 65% between 2000 and 2020.[n 7] The report identified that the speed of vehicles was 'at the core of the problem[n 8] and said that speed limits should be set appropriately for the road function and design along with physical measures related to the road and the vehicle and effective enforcement by the police.[n 9] Road incidents are said to be the leading cause of deaths among children 10 – 19 years of age (260,000 children die a year, 10 million are injured).[33] They are also occasionally set to reduce vehicle emissions or fuel use.

Maximum speed limits place an upper limit on speed choice and if obeyed can reduce the differences in vehicle speeds by drivers using the same road at the same time.[n 10] Traffic engineers observe that the likelihood of a crash happening is significantly higher if vehicles are traveling at speeds faster or slower than the mean speed of traffic;[n 11] when severity is taken into account the risk is lowest for those traveling at or below the median speed and "increases exponentially for motorists driving faster".[n 12]

It is desirable to attempt to reduce the speed of road vehicles in some circumstances because the kinetic energy involved in a motor vehicle collision is proportional to the square of the speed at impact. The probability of a fatality is, for typical collision speeds, empirically correlated to the fourth power of the speed difference (depending on the type of collision, not necessarily the same as travel speed) at impact,[34] rising much faster than kinetic energy.

The 2009 technical report An Analysis of Speeding-Related Crashes:Definitions and the Effects of Road Environments by the National Highway Traffic Safety Administration showed that ca 55 percent of all speeding-related crashes in fatal crashes were due to “exceeding posted speed limits” and 45 percent were due to “driving too fast for conditions”.[35]

The speed limit will also take note of the speed at which the road was designed to be driven (the design speed) which is defined in the USA as "a selected speed used to determine the various geometric design features of the roadway".[36]. However traffic engineers recognize that "operating speeds and even posted speed limits can be higher than design speeds without necessarily compromising safety". [37]

Motorways/freeways/Autobahns etc. have higher design speeds with limited access, grade separation and slower and more vulnerable road users are banned. Rural roads can be quite dangerous even with speed limits that appear low by comparison. For example, in 2008, the overall German road network had 6.5 deaths per billion travel-kilometer, yet autobahn had a death rate of 2.2 while major rural roads had a rate of 9.5 deaths.[38] Autobahns accounted for 33% of German road travel in 2008,[39] but just 11% (495 of 4,477) of traffic deaths.

Fuel efficiency

Fuel efficiency sometimes affects speed limit selection. The United States instituted a National Maximum Speed Law of 55 mph (89 km/h) as part of the Emergency Highway Energy Conservation Act in response to the 1973 oil crisis to reduce fuel consumption.[40] According to a report published in 1986 by The Heritage Foundation, a Conservative advocacy group, the law was widely disregarded by motorists and hardly reduced consumption at all.[41] In 2009 The American Trucking Associations called for a 65 mph speed limit and also st national fuel economy standards claiming that the lower speed limit was not effective at saving fuel.[42]

Environmental considerations

Speed limits can also be used to local air quality issues or other factors affecting environmental quality for example the "environmental speed limits" in the United States including one in an area of Texas.[43]

The European Union is also increasingly using Speed Limits as in response to environmental concerns.[32]

Advocacy

See also: advocacy groups

Speed limits, and especially some of the methods used to attempt to enforce them, have always been controversial. There are a variety of notable organisations and individuals who, for a variety of often passionately held views, oppose or support the use of speed limits or the way they are enforced.

Opposition

Speed limits, and their enforcement have been opposed by various groups and for various reasons since their inception. Historically, the AA was formed in 1905, initially to warn members about speed traps.[44]

In more recent times some advocacy groups seek to have certain speed limits as well as other measures removed. For example, automated camera enforcement has been criticised by motoring advocacy groups the Association of British Drivers,[45][46] the North American National Motorists Association,[47][48] and the German Auto Club.[49]

Arguments used by those advocating a relaxation of speed limits or their removal include:

Support

Various other advocacy groups press for stricter limits and better enforcement. Historically, the Pedestrians' Association and the Automobile Association were described as "bitterly opposed" in the early years of United Kingdom motoring legislation.[56] The Pedestrians Association was formed in the United Kingdom in 1929 to protect the interests of the pedestrian. Their president published a critique of motoring legislation and the influence of motoring groups in 1947 title 'Murder most foul' which laid out in an emotional but detailed way the situation as they saw it and called for tighter speed limits.[57] More recently RoadPeace was founded in 1991 with an aim to stop road victims being "treated by the economy as acceptable, by the judicial system as trivial and by society as accidents" and called for a default 20 mph speed limit in residential areas.[58]

The Insurance Institute for Highway Safety (IIHS), an organization wholly controlled by major insurance companies, generally advocates for lower speed limits and provides grants to police agencies to obtain speed enforcement equipment, such as radar and lidar guns. Skeptics believe that the IIHS's interest in promoting lower limits and the issuance of more traffic tickets arises out of the industry's interest in increasing motorists' insurance rates, leading to greater profits for its constituents.

See also

Notes

  1. ↑ World Heath Organisation (2004) p. foreword, "In high-income countries, an established set of interventions have contributed to significant reductions in the incidence and impact of road traffic injuries. These include the enforcement of legislation to control speed and alcohol consumption, mandating the use of seat-belts and crash helmets, and the safer design and use of roads and vehicles."
  2. ↑ Department for Transport (2008), p.178 "Introduction of trial speed limit of 70 mph on motorways and other previously"
  3. ↑ Federal Highway Administration (1998) p. 2 'In general, changing speed limits on low and moderate speed roads appears to have little or no effect on speed and thus little or no effect on crashes. This suggests that drivers travel at speeds they feel are reasonable and safe for the road and traffic regardless of the posted limit. However, on freeways and other high-speed roads, speed limit increases generally lead to higher speeds and crashes. The change in speed is roughly one-fourth the change in speed limit. Results from international studies suggest that for every 1 mi/h change in speed, injury accidents will change by 5 percent (3 percent for every 1km/h). However there is limited evidence that suggests the net effect of speed limits may be positive on a system wide basis.'
  4. ↑ 4.0 4.1 4.2 British Columbia Ministry of Transportation (2003), p. 26 tables 10 and 11
  5. ↑ Federal Highway Administration (1998) p. 2 'In general, changing speed limits on low and moderate speed roads appears to have little or no effect on speed and thus little or no effect on crashes. This suggests that drivers travel at speeds they feel are reasonable and safe for the road and traffic regardless of the posted limit. However, on freeways and other high-speed roads, speed limit increases generally lead to higher speeds and crashes. The change in speed is roughly one-fourth the change in speed limit. Results from international studies suggest that for every 1 mi/h change in speed, injury accidents will change by 5 percent (3 percent for every 1km/h).'
  6. ↑ World Heath Organisation (2004) p. 34 fig 2.1
  7. ↑ World Heath Organisation (2004) p. 3
  8. ↑ World Heath Organisation (2004) p. 76
  9. ↑ World Heath Organisation (2004) p. 127
  10. ↑ Federal Highway Administration (1998) p. 2
  11. ↑ British Columbia Ministry of Transportation (2003), p. v 'The likelihood of a crash occurring is significantly greater for motorists traveling at speed slower and faster than the mean speed of traffic'
  12. ↑ Federal Highway Administration (1998) page 2 'When the consequences of crashes are taken into account, the risk of being involved in an injury crash is lowest for vehicles that travel near the median speed or slower and increases exponentially for motorists traveling much faster'

References

Documents referenced from 'Notes' section
Other references for article
  1. ↑ 1.0 1.1 "No All-Island Speed Limit". Isle of Man Guide. 6 November 2004. http://www.iomguide.com/news/general-news.php?story=697. Retrieved 2009-09-17. 
  2. ↑ "Current speed limit policies". European Commission. http://ec.europa.eu/transport/road_safety/specialist/knowledge/speed/speed_limits/current_speed_limit_policies.htm. Retrieved 2010-04-23. 
  3. ↑ "Motoring firsts". National Motoring Museum. http://www.nationalmotormuseum.org.uk/motoring_firsts. 
  4. ↑ Adam Hart Davis. "The Eureka Years". BBC Radio 4. http://www.bbc.co.uk/programmes/b00cmb4q. 
  5. ↑ "US History, Criminal Justice, The first speeding ticket". http://en.allexperts.com/q/U-S-History-672/criminal-justice-history.htm. 
  6. ↑ William Powden (1971). The Motor Car and Politics 1896-1970. The Bodley Head. ISBN 0370003934. 
  7. ↑ "How Road Signs Help to Provide a Safe Road System" (PDF). Government of Western Australia. http://www2.mainroads.wa.gov.au/Internet/Safety/road_environment/roadsides/road_signs.asp. Retrieved 2009-09-17. 
  8. ↑ 8.0 8.1 "An Analysis of Speeding-Related Crashes:Definitions and the Effects of Road Environments". U.S. Department of Transportation, National Highway Traffic Safety Administration. February 2009. http://www-nrd.nhtsa.dot.gov/Pubs/811090.PDF. Retrieved 2010-04-25. "Appendix: The basic rules governing speed of vehicles in Kansas, Kentucky, Maryland, Montana, North Carolina, and Wisconsin." 
  9. ↑ "Road Traffic Act 1991". Office of Public Sector Information. http://www.opsi.gov.uk/acts/acts1991/ukpga_19910040_en_2#pt1-pb4-l1g6. Retrieved 2010-05-03. "A person is guilty of an offence if he intentionally and without lawful authority or reasonable cause— (a) causes anything to be on or over a road, or (b) interferes with a motor vehicle, trailer or cycle, or (c) interferes (directly or indirectly) with traffic equipment, in such circumstances that it would be obvious to a reasonable person that to do so would be dangerous. (2) In subsection (1) above “dangerous” refers to danger either of injury to any person while on or near a road, or of serious damage to property on or near a road; and in determining for the purposes of that subsection what would be obvious to a reasonable person in a particular case, regard shall be had not only to the circumstances of which he could be expected to be aware but also to any circumstances shown to have been within the knowledge of the accused." 
  10. ↑ "California Vehicle Code section 22350: Basic Speed Law". California Department of Motor Vehicles. September 20, 1963.. http://www.dmv.ca.gov/pubs/vctop/d11/vc22350.htm. Retrieved 2010-04-25. "No person shall drive a vehicle upon a highway at a speed greater than is reasonable or prudent having due regard for weather, visibility, the traffic on, and the surface and width of, the highway, and in no event at a speed which endangers the safety of persons or property." 
  11. ↑ (PDF) Report (HC 15, 2004-05): Tackling congestion by making better use of England's motorways and trunk roads (Full Report), National Audit Office, 26 November 2004, p. 21, http://www.nao.org.uk/publications/nao_reports/04-05/040515.pdf, retrieved 2009-09-17, "The initial results of the one year trial of Variable Speed Limits indicated savings in journey times, smoother flowing traffic and a fall in the number of accidents. On the basis of these findings, the Agency converted the trial into a permanent facility in 1997. Variable Speed Limits have generally been popular with road users who have reported perceived benefits, including less congestion and less stressful journeys. Yet the Agency could not prove a business case to use the measure elsewhere. Conditions at the site of the Variable Speed Limits trial were not stable before or during the trial, or in the period of extended monitoring that followed it. Traffic volumes changed and the Agency introduced new technology and new lighting and widened the motorway at both ends of the trial site, preventing it from establishing properly controlled and reliable “before and after” data to assess the measure’s impact. Without reliable data, the Agency could not prove a business case to use the measure elsewhere. As a result, in 2002 the Agency extended the Variable Speed Limits trial, at a further budgeted cost of £3.9 million, to cover an additional eight kilometres of the M25, where conditions were expected to be more stable, in order to collect sufficient before and after data to prepare a business case." 
  12. ↑ "M1 Junctions 6A to 10 Official Completion Ceremony". Highways Agency. http://www.highways.gov.uk/roads/documents/M1_Official_Completion_Ceremony.pdf. 
  13. ↑ "M1 works speed cameras will stay". BBC News. 2010-01-03. http://news.bbc.co.uk/1/hi/england/nottinghamshire/8438375.stm. Retrieved 2010-04-13. 
  14. ↑ "Managing Speed". Public Roads. www.tfhrc.gov. January/February 2003. http://www.tfhrc.gov/pubrds/03jan/10.htm. Retrieved 2008-07-06. 
  15. ↑ FindLaw for Legal Professionals - Case Law, Federal and State Resources, Forms, and Code
  16. ↑ "Speed limits to be introduced on NT open roads". Australian Broadcasting Corporation. 2 November 2006. http://www.abc.net.au/7.30/content/2006/s1780096.htm. Retrieved 2009-09-17. 
  17. ↑ "Northern Territory Crash Statistics". Northern Territory Transport Group. http://www.roadsafety.nt.gov.au/stats/index.shtml. Retrieved 2010-04-27. 
  18. ↑ "NT has worst road toll in OECD nations". "A report on road deaths in 2007 shows the Northern Territory had by far the highest per capita rate of fatalities when compared with the rest of Australia and OECD countries." 
  19. ↑ "Call to scrap Northern Territory speed limits". Perth Now (Sunday Times). 2007-12-27. http://www.perthnow.com.au/news/top-stories/speed-limits-blamed-for-nt-toll/story-e6frg12l-1111115207569. Retrieved 2010-04-26. 
  20. ↑ "Transport Implications of the Isle of Man Strategic Plan: Report" (PDF). JMP Consulting. 2007-04-27. http://www.gov.im/lib/docs/dlge/planning/publications/transportimplicationsofthestrate.pdf. Retrieved 2008-04-29. 
  21. ↑ "Traffic Safety - The German Experience after Reunification" (PDF). German Society for Technical Cooperation. 2004-11-06. http://www.gtz.de/de/dokumente/en-traffic-safety-reunification-2006.pdf. Retrieved 2009-09-17. 
  22. ↑ Speed Zoning Information. Institute of Transport Engineers. 22 March 2004. http://www.ite.org/standards/speed_zoning.pdf. Retrieved 2009-09-17. 
  23. ↑ . p. 88. http://trb.org/publications/nchrp/nchrp_rpt_504.pdf. Retrieved 2009-09-16. 
  24. ↑ EFFECTS OF THE 65-MPH SPEED LIMIT ON TRAFFIC ACCIDENTS IN OHIO. University of Cincinnati. 1992. http://pubsindex.trb.org/view.aspx?id=371649. Retrieved 2010-07-10. ""fatal accident rates on rural Interstate highways posted at 65 mph or rural non-Interstate highways posted at 55 mph had not significantly changed after the implementation of the 65-mph speed limit."". 
  25. ↑ "Several New Laws Now In Effect". Channel 6 News, Indianapolis. 2005-07-01. http://www.theindychannel.com/news/4674232/detail.html. Retrieved 2010-07-10. ""Speed limits are set to increase on rural interstates to 70 mph for cars -- 65 mph for semitrailers. Officials said they're waiting until after the [July 4th] holiday weekend to put up the new signs"" 
  26. ↑ Study: Higher interstate speed limit proves safe for Indiana. Purdue University. 23 June 2008. http://www.purdue.edu/uns/x/2008a/080623ManneringSpeed.html. Retrieved 2010-07-10. ""If going from 65 to 70 doesn't have a significant effect on the severity of accidents, you have to ask yourself, what about 70 to 75?" Mannering said. "At what point does it begin to impact safety?"". 
  27. ↑ UDOT says drivers going slower in 80 mph zones. Deseret News. 2009-10-26. http://www.deseretnews.com/article/705338447/UDOT-80-mph-limit-slows-speeders.html. Retrieved 2010-07-10. "With an 80 mph posted speed limit, people are driving 81 mph to 85 mph, said Carlos Braceras, UDOT deputy director. With a 75 mph posted speed limit, people were driving 83 mph to 85 mph...The speeds [reflect] the behavior of 85 percent of the drivers". 
  28. ↑ "South Dakota Speed Monitoring" (PDF). South Dakota Department of Transportation. 2008. http://www.sddot.com/pe/data/Docs/SPEED2008.pdf. Retrieved 2009-09-17. 
  29. ↑ "Written Answers to Questions: Road Accidents". Hansard. House of Commons. 2003-01-31. http://www.publications.parliament.uk/pa/cm200102/cmhansrd/vo020131/text/20131w01.htm. Retrieved 2010-04-23. "TRL research on urban speed management methods published in 1998 (TRL Report 363) found only an average 1 mph drop in speeds and no discernible accident reduction in accidents in 20 mph limits using only signs. Advisory speed limits are not normally approved in England and Wales. However, the more successful 20 mph zones that use self enforcing traffic calming features achieved average speed reductions of around 10 mph which produced a 70 per cent. reduction in child pedestrian accidents and a 48 per cent. reduction in child cyclist accidents." 
  30. ↑ "A 50 km/h default urban speed limit for Australia?". Monash University Accident Research Centre. http://www.monash.edu.au/cemo/roadsafety/abstracts_and_papers/125/hawcor.pdf. Retrieved 2010-04-26. "After Norway reduced its urban speed limit from 60 km/h to 50 km/h, the average speed fell by 3.5-4 km/h and the number of fatal accidents was reduced by 45 per cent (Norwegian Traffic Safety Handbook, cited in 9)... The bulk of the casualty crash benefit relates to implementation of 50 km/h default speed limits on urban arterials currently zoned 60 km/h. Extending the default 50 km/h urban speed limit to all residential streets across Australia contributes about 6% of the total saving in casualty crashes." 
  31. ↑ "50 km/h Urban Speed Limit Evaluation". NSW Road and Traffic Authority. http://www.rta.nsw.gov.au/roadsafety/downloads/50eval.pdf. Retrieved 2010-04-26. 
  32. ↑ 32.0 32.1 "Current speed limit policies". European Commission. http://ec.europa.eu/transport/road_safety/specialist/knowledge/speed/speed_limits/current_speed_limit_policies.htm. Retrieved 2010-04-23. "A speed limit is based on both safety and mobility considerations and increasingly also on environmental considerations... his requires that an upper limit is put on the injury risk that could occur on the road (e.g. virtually eliminating the chance of a fatality occurring). The speed limit and the design of the road infrastructure would then be matched to ensure that the injury risk was not exceeded." 
  33. ↑ "UN raises child accidents alarm". BBC News. http://news.bbc.co.uk/2/hi/in_depth/7776127.stm. 
  34. ↑ Synthesis of Safety Research Related to Speed and Speed Limits. Federal Highway Administration. 1998. http://safety.fhwa.dot.gov/speedmgt/ref_mats/fhwasa09028/resources/Synthesis%20of%20Safety%20Researc...pdf. Retrieved 2009-09-17. 
  35. ↑ Liu, Cejun; Chen, Chou-Lin (2009). An Analysis of Speeding-Related Crashes:Definitions and the Effects of Road Environments. National Highway Traffic Safety Administration. 
  36. ↑ "Design Speed, Operating Speed, and Posted Speed Practices (Report 504)" (PDF). National Cooperative Highway Research Program. http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_504.pdf. 
  37. ↑ "Design Speed, Operating Speed, and Posted Speed Practices (Report 504)" (PDF). National Cooperative Highway Research Program. http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_504.pdf. "A significant concern with the 1954 design speed concept was the language of the definition and its relationship with operational speed measures. The term “maximum safe speed” is used in the definition, and it was recognized that operating speeds and even posted speed limits can be higher than design speeds without necessarily compromising safety. In 1997, Fambro et al. (15) recommended a revised definition of design speed for the Green Book while maintaining the five provisions noted above. The definition recommended was, “The design speed is a selected speed used to determine the various geometric design features of the roadway.” The term “safe” was removed in order to avoid the perception that speeds greater than the design speed were “unsafe.” The AASHTO Task Force on Geometric Design voted in November 1998 to adopt this definition and it was included in the 2001 Green Book (17)." 
  38. ↑ (in German) Traffic accidents (2008). [http://de.wikipedia.org/wiki/Bundesanstalt_f%C3%BCr_Stra%C3%9Fenwesen.+October 2009. http://www.bast.de/cln_005/nn_76770/EN/e-Statistik/e-Unfalldaten/downloads/e-strassenverkehrsunfaelle,templateId=raw,property=publicationFile.pdf/e-strassenverkehrsunfaelle.pdf. Retrieved 2010-04-21. 
  39. ↑ (in German) [http://www.bast.de/cln_007/nn_76758/EN/e-Statistik/e-Verkehrsdaten/Download//e-verkehrsdaten,templateId=raw,property=publicationFile.pdf/e-verkehrsdaten.pdf Traffic and Accident Data Summary Statistics - Germany (2008)]. (German) Federal Highway Research Institute. http://www.bast.de/cln_007/nn_76758/EN/e-Statistik/e-Verkehrsdaten/Download//e-verkehrsdaten,templateId=raw,property=publicationFile.pdf/e-verkehrsdaten.pdf. Retrieved 2010-04-21. 
  40. ↑ Nevada brief in Nevada v. Skinner
  41. ↑ Copulos, Milton R. (1986-09-09). The High Cost of the 55 MPH Speed Limit. The Heritage Foundation. http://www.heritage.org/Research/SmartGrowth/bg532.cfm. Retrieved 2007-04-19. 
  42. ↑ "Trucking Industry Asks Congress for National 65 mph Speed Limit". Environment News Service. January 27, 2009. http://www.ens-newswire.com/ens/jan2009/2009-01-27-093.asp. Retrieved 2009-02-08. 
  43. ↑ "Vehicular Speed-Limit Reduction". Texas Commission on Environmental Quality. 2002. http://www.tceq.state.tx.us/implementation/air/sip/speedlimit.html. Retrieved 2010-04-13. 
  44. ↑ "AA History, The story of the AA since 1905". The Automobile Association. http://www.theaa.com/aboutaa/history.html. Retrieved 2008-10-26. ""A group of motoring enthusiasts met at the Trocadero restaurant in London's West End on 29 June to form the Automobile Association (the AA) – a body initially intended to help motorists avoid police speed traps."" 
  45. ↑ "Speed Limits — How they are set and your Right to Object". Association of British Drivers. http://www.abd.org.uk/speedobj.htm. Retrieved 2010-04-17. 
  46. ↑ "Speed Cameras". Association of British Drivers. http://www.abd.org.uk/speed_cameras.htm. Retrieved 2010-04-17. "Thousands of motorists are losing their jobs, freedom and ability to earn a living. 82% of speed camera victims thought they were driving safely at the time of their conviction and were just unfortunate to be doing a few miles over the limit. 65% thought their speeding ticket was totally unjustified and felt cheated." 
  47. ↑ "About us". National Motorists Association. http://www.motorists.org/aboutus/. Retrieved 2010-04-18. "We work for more reasonable speed limits" 
  48. ↑ "NMA Objections To Photo Enforcement". National Motorists Association. http://www.motorists.org/photoenforce/. Retrieved 2010-04-18. 
  49. ↑ "Autobahn-Temporegelung". http://www.presse.adac.de/standpunkte/Verkehr/Autobahn_Temporegelung.asp?active1=tcm:11-18784-4. Retrieved 2008-10-25. ""German:Der ADAC hält ein allgemeines Tempolimit auf Autobahnen für nicht erforderlich... Ein Zusammenhang zwischen generellem Tempolimit und dem Sicherheitsniveau auf Autobahnen ist im internationalen Vergleich nicht feststellbar. Die Zahl der Getöteten auf Autobahnen pro 1 Mrd. Fahrzeugkilometer liegt in Deutschland bei 2,99 mit fallender Tendenz. Zahlreiche Länder mit genereller Geschwindigkeitsbeschränkung schneiden schlechter ab als Deutschland (z.B. Belgien, Österreich, Slowenien, Tschechien, USA). English: ADAC holds a general speed limit on motorways to be unnecessary... A connection between general speed limit on highways and the security level is not detectable by international standards. The number of deaths on motorways per 1 billion vehicle-kilometers in Germany is 2.99 with a falling trend. Many countries fare worse with a general speed limit than Germany (eg Belgium, Austria, Slovenia, Czech Republic, USA). In Austria, where speed is generally 130, the death rate on motorways is about 1.5 times higher "" , Press Release, October 2007.
  50. ↑ Lave, Charles. Did the 65 mph Speed Limit Save Lives?. University of California Transportation Center. http://www.uctc.net/papers/069.pdf. Retrieved 2010-04-20. "'This study analyzes the statewide consequences of raising the speed limit, treating highways and enforcement as a total system. We find that the 65 mph speed limit reduced the statewide fatality rate by 3.4%-5.1%, compared to those states that did not raise their speed limit.on rural interstate highways [p.49] VMT grew 1.62 times faster in the 65 mph states than it did in the 55 mph states...These numbers are consistent with the expected pattern of traffic shifts [p.53]'". 
  51. ↑ Peters, Eric (24 November 1998). "Highways Are Safe at Any Speed". Wall Street Journal. Junk Science. http://www.junkscience.com/nov98/peters2.html. Retrieved 2009-09-17. "When speed limits are set arbitrarily low--as under the old system--tailgating, weaving and "speed variance" (the problem of some cars traveling significantly faster than others) make roads less safe" 
  52. ↑ "Autobahn-Temporegelung". http://www.presse.adac.de/standpunkte/Verkehr/Autobahn_Temporegelung.asp?active1=tcm:11-18784-4. Retrieved 2008-10-25. ""German:Der ADAC hält ein allgemeines Tempolimit auf Autobahnen für nicht erforderlich... Ein Zusammenhang zwischen generellem Tempolimit und dem Sicherheitsniveau auf Autobahnen ist im internationalen Vergleich nicht feststellbar. Die Zahl der Getöteten auf Autobahnen pro 1 Mrd. Fahrzeugkilometer liegt in Deutschland bei 2,99 mit fallender Tendenz. Zahlreiche Länder mit genereller Geschwindigkeitsbeschränkung schneiden schlechter ab als Deutschland (z.B. Belgien, Österreich, Slowenien, Tschechien, USA). English: ADAC holds a general speed limit on motorways to be unnecessary... A connection between general speed limit on highways and the security level is not detectable by international standards. The number of deaths on motorways per 1 billion vehicle-kilometers in Germany is 2.99 with a falling trend. Many countries fare worse with a general speed limit than Germany (eg Belgium, Austria, Slovenia, Czech Republic, USA). In Austria, where speed is generally 130, the death rate on motorways is about 1.5 times higher "" , Press Release, October 2007.
  53. ↑ "Speed limits". Safe Speed. http://www.safespeed.org.uk/speedlimits.html. Retrieved 2010-04-17. ""Note that the "average" driver at the 50% percentile has a greater crash risk than the 85th percentile driver. Below the 30th percentile crash risk is significantly increased and these speeds tend to be used by less skilled and competent drivers ... Doddery old fool at 30 mph on a UK "A" road suitable for 60 mph. Of course he has an elevated crash risk. He does not know what he is doing ... A single vehicle in lane 3 of a busy motorway. It's obvious that as the speed is reduced below 55 mph the crash risk will increase"" 
  54. ↑ "Welcome to Safe Speed". Safe Speed. http://www.safespeed.org.uk/. Retrieved 2010-04-18. ""In March we learned via Freedom of Information request that the speed camera side effects research (announced in May 2005) had been axed. It is inconceivable that the side effects DON'T cost more than 25 lives per year, meaning that speed cameras are making road safety worse. But DfT doesn't want to hear this, which is the only possible reason for axing the most important research. So here's the truth. Speed camera policy has failed catastrophically. Department for Transport KNOWS that it has failed but won't admit their deadly mistake and pull the plug."" 
  55. ↑ "'Scrap speed cameras now'". The Telegraph. 2007-06-23. http://www.telegraph.co.uk/motoring/road-safety/2747604/Scrap-speed-cameras-now.html. Retrieved 2010-04-17. 
  56. ↑ Criminal on the road. Tavistock Publications. 1964. p. 102. http://books.google.co.uk/books?id=kjyua9Ood38C&printsec=frontcover&dq=Criminal+on+the+Road++By+T.+C.+Willett&source=bl&ots=l4Aq65IlLm&sig=cIV44ueFdIwoOa450NeOz0QWnzU&hl=en&ei=As3IS4zTPJT40wS8nZTgDQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAYQ6AEwAA#v=onepage&q=automobile%20association&f=true. Retrieved 2010-04-27. "Moreover it has been the result of continued compromise between two bitterly opposed factions: those who are against the motorist and will do all they can to constrain him, and those who oppose constraints unless they are relatively minor in their effects. Examples of both sides are, respectively, the Pedestrians' Association and the Automobile Association. The survey shows also that motoring law in 1903 and 1930 wa framed by legislators who knew little of the motor vehicle." 
  57. ↑ J.S.Dean. "Murder most foul". http://issuu.com/carltonreid/docs/murder-most-foul. 
  58. ↑ "Safer Streets". RoadPeace. http://www.roadpeace.org/change/safer_streets/. Retrieved 2010-04-27. "RoadPeace, along with CTC, LCC, Living Streets, and 20s plenty is campaigning for 20 mph default speed limit in all residential areas" 

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