GetWiki

{{Short description|Maximum legal speed of vehicles}}{{About|road speed limits|the speed of light|Special relativity|road speed limits in specific countries|Speed limits by country|rail speed limits|Slow zone}}{{Redirect|Speed Limit|the video game|Speed Limit (video game)|the Austrian heavy metal band|Speed Limit (band)}}{{Use dmy dates|date=May 2024}}File:Expwy Spdlmt CHN.jpg|thumb|A road sign shows maximum and minimum speed limit for different types of vehicle on expressway in China. Speed limit signs are shown in kilometres per hourkilometres per hourSpeed limits on road traffic, as used in most countries, set the legal maximum speed at which vehicles may travel on a given stretch of road.MINIMUM SPEED: REGULATION AND PENALTIES IN AUSTRIA, 23.02.2016, Autorevue Austria. Speed limits are generally indicated on a traffic sign reflecting the maximum permitted speed, expressed as kilometres per hour (km/h) or miles per hour (mph) or both. 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 Autobahnen in Germany.WEB,weblink Driving on the Autobahn, www.german-way.com, 2019-04-14, The first numeric speed limit for automobiles was the {{cvt|10|mph|0}} limit introduced in the United Kingdom in 1861.BOOK,weblink Traffic Networks as Information Systems: A Viability Approach, Aubin, Jean-Pierre, Désilles, Anya, 2016-07-13, Springer, 9783642547713, {{As of | 2018}} the highest posted speed limit in the world is {{cvt|160|km/h|0}}, applied on two motorways in the UAE.NEWS,weblink New speed limit for Abu Dhabi's Mafraq-Ghweifat highway - ARN News Centre, 2018-01-30, ARN News Centre, 2018-01-31,weblink 2018-01-31, dead, Speed limits and safety distance are poorly enforced in the UAE, specifically on the Abu Dhabi to Dubai motorway – which results in dangerous traffic, according to a French government travel advisory.WEB,weblink Emirats arabes unis- Dernière minute, 22 April 2024, Additionally, "drivers often drive at high speeds [and] unsafe driving practices are common, especially on inter-city highways. On highways, unmarked speed bumps and drifting sand create additional hazards", according to a travel advisory issued by the U.S. State Department.WEB,weblink United Arab Emirates International Travel Information, There are several reasons to regulate speed on roads. It is often done in an attempt to improve road traffic safety and to reduce the number of casualties from traffic collisions. The World Health Organization (WHO) identified speed control as one of a number of steps that can be taken to reduce road casualties.{{harvtxt|World Health Organization |2004}} As of 2021, the WHO estimates that approximately 1.3 million people die of road traffic crashes each year.WEB, Pietrasik, T, 21 June 2021, Road traffic injuries,weblink 2021-12-25, www.who.int, Authorities may also set speed limits to reduce the environmental impact of road traffic (vehicle noise, vibration, emissions) or to enhance the safety of pedestrians, cyclists, and other road-users. For example, a draft proposal from Germany's National Platform on the Future of Mobility task force recommended a blanket 130 km/h (81 mph) speed limit across the Autobahnen to curb fuel consumption and carbon emissions.NEWS,weblink Germany considers Autobahn speed limit to fight climate change, 2019-01-21, The Local Germany, en-GB, 2019-04-14, Some cities have reduced limits to as little as {{convert|30|km/h|abbr= on}} for both safety and efficiency reasons.WEB,weblink The impact of lowered speed limits in urban and metropolitan areas, However, some research indicates that changes in the speed limit may not always alter average vehicle speed.BOOK, Parker, M. R. Jr., Effects of Raising and Lowering Speed Limits on Selected Roadway Sections, FHWA-RD-9 7-084, 1997, Federal Highway Commission, Washington DC, 85–87,weblink 5 February 2017, There is statistically sufficient evidence [...] to reject the hypothesis that driver speeds do not change when posted speed limits are either raised or lowered., Lower speed limits could reduce the use of over-engineered vehicles.BOOK }}

History

{{Globalize|section|date=August 2015}}File:Antique New Hampshire speed limit sign.jpg|thumb|Historic New HampshireNew HampshireIn Western cultures, speed limits predate the use of motorized vehicles. In 1652, the American colony of New Amsterdam passed a law stating, "No wagons, carts or sleighs shall be run, rode or driven at a gallop". The punishment for breaking the law was "two pounds Flemish", the equivalent of US $50 in 2019.WEB,weblink Connecticut enacts first speed-limit law, history.com, 2019-04-14, The 1832 Stage Carriage Act introduced the offense of endangering the safety of a passenger or person by "furious driving" in the United Kingdom (UK).BOOK, Criminal on the Road:A Study of Serious Motoring Offences and Those Who Commit Them, 1964, Routledge, 0415264162, 64, In 1872, then-President of the United States Ulysses S. Grant was arrested for speeding in his horse-drawn carriage in Washington, D.C.WEB, Kemp, Ben, 2018-05-18, The Thin Blue Line,weblink 2023-04-02, Ulysses S. Grant Cottage National Historic Landmark, en-US, NEWS, Rosenwald, Michael S., The police officer who arrested a president,weblink 2023-04-02, The Washington Post, 2018-12-16, A series of Locomotive Acts (in 1861, 1865 and 1878) created the first numeric speed limits for mechanically propelled vehicles in the UK; the 1861 Act introduced a UK speed limit of {{cvt|10|mph}} on open roads in town, which was reduced to {{cvt|2|mph|0}} in towns and {{cvt|4|mph|0}} in rural areas by the 1865 "Red Flag Act".WEB,weblink Locomotive Act 1861, www.legislation.gov.uk, 2019-04-14, The Locomotives on Highways Act 1896, which raised the speed limit to {{cvt|14|mph}} is celebrated by the annual London to Brighton Veteran Car Run.{{Citation needed|date=June 2019}}On 28 January 1896, the first person to be convicted of speeding is believed to be Walter Arnold of East Peckham, Kent, UK, who was fined 1 shilling plus costs for speeding at {{cvt|8|mph}}.WEB,weblink National Motoring Museum, Motoring firsts, 2009-12-01, 2016-01-14,weblink" title="web.archive.org/web/20160114042029weblink">weblink dead, WEB,weblink BBC Radio 4, The Eureka Years, Adam Hart Davis, WEB,weblink US History, Criminal Justice, The first speeding ticket, dead,weblink" title="web.archive.org/web/20100503020127weblink">weblink 2010-05-03, File:19200820 D. C. Pastor Fined for Speed and Contempt - The Washington Times.jpg|thumb|right|upright=1.3|In 1920 a pastor was fined US$10 for "overspeeding his machine ... at a rate greater than {{cvt|25|mph}} ... in what appeared to be a reckless manner."NEWS, D. C. Pastor Fined for Speed and Contempt in N. H. Police Court,weblink Washington Times (1894–1939), The Washington TimesWashington Times (1894–1939), The Washington TimesIn 1901, Connecticut was the first state in the United States to impose a numerical speed limit for motor vehicles, setting the maximum legal speed to {{cvt|12|mph}} in cities and {{cvt|15|mph}} on rural roads. Speed limits then propagated across the United States; by 1930 all but 12 states had established numerical limits.In 1903, in the UK, the national speed limit was raised to {{cvt|20|mph}}; however, as this was difficult to enforce due to the lack of speedometers, the 1930 "Road Traffic Act" abolished speed limits entirely. In 1934, a new limit of {{cvt|30|mph}} was imposed in urban centers, and in July 1967, a {{cvt|70|mph}} national speed limit was introduced.WEB,weblink The history of speed limits in the UK, 2017-06-20, Read Cars, 2019-04-14, In Australia, during the early 20th century, there were people reported for "furious driving" offenses. One conviction in 1905 cited a vehicle furiously driving {{cvt|20|mph}} when passing a tram traveling at half that speed.WEB, Keeping Order: Motor-Car Regulation and the Defeat of Victoria's 1905 Motor-Car Bill,weblink On 7 April 1905, E Norton Grimwade ...appeared in the District Court [charged with] ‘furious’ driving [because] he passed a tram ... Several people ... [estimated] the car’s speed at 20 mph ... It was going twice as fast as the tram., 2015-02-25, 2015-03-18,weblink" title="web.archive.org/web/20150318045808weblink">weblink dead, In May 1934, the Nazi-era "Road Traffic Act" imposed the first nationwide speed limit in Germany.{{CN|date=January 2023}}In the 1960s, in continental Europe, some speed limits were established based on the V85 speed, (so that 85% of drivers respect this speed).In 1974, Australian speed limits underwent metrication: the urban speed limit of {{cvt|35|mph}} was converted to {{cvt|60|kph}}; the rural speed limits of {{cvt|60|mph}} and {{cvt|65|mph}} were changed to {{cvt|100|kph}} and {{cvt|110|kph}} respectively.BOOK, A Review of Rural Speed Limits in Australia, Cowley, J.E., 1980, The Office of Road Safety Commonwealth Department of Transport, In 2010, Sweden defined the Vision Zero program, a multi-national road traffic safety project that aims to achieve a highway system with no fatalities or serious injuries involving road traffic.

Regulations

(File:World Speed Limits.svg|thumb|upright=1.5|Highest-posted speed limits around the world. Kilometres per hour are on the left and miles per hour on the right.*)File:World Map of Speed Limit Units on Traffic Signs.svg|thumb|upright=1.5|Speed limit units on (traffic sign]]s around the world:{{legend|#005ce6|Kilometres per hour (km/h)}}{{legend|#ff8000|Miles per hour (mph)}}{{legend|#22b14c|Both}}{{legend|#c0c0c0|none known}})Most countries use the metric speed unit of kilometres per hour, while others, including the United States, United Kingdom, and Liberia, use speed limits given in miles per hour.

Vienna Convention on Road Traffic

In countries bound by the Vienna Conventions on Road Traffic (1968 & 1977), Article 13 defines a basic rule for speed and distance between vehicles:Vienna Convention on Road Traffic{{Blockquote|Every driver of a vehicle shall in all circumstances have his vehicle under control to be able to exercise due and proper care and to be at all times in a position to perform all manœuvres required of him. He shall, when adjusting the speed of his vehicle, pay constant regard to the circumstances, in particular the lie of the land, the state of the road, the condition and load of his vehicle, the weather conditions and the density of traffic, so as to be able to stop his vehicle within his range of forward vision and short of any foreseeable obstruction. He shall slow down and if necessary stop whenever circumstances so require, and particularly when visibility is not excellent.}}

Reasonable speed

Most legal systems expect drivers to drive at a safe speed for the conditions at hand, regardless of posted limits.In the United Kingdom, and elsewhere in common law, this is known as the reasonable man requirement.WEB,weblink Road Traffic Act of 1991, 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., 2010-05-03, Office of Public Sector Information, The German Highway Code (Straßenverkehrs-Ordnung) section on speed begins with the statement (translated to English):WEB,weblink § 3 StVO 2013 - Einzelnorm, www.gesetze-im-internet.de, 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.In France, the law clarifies that even if the speed is limited by law and by local authority, the driver assumes the responsibility to control a vehicle's speed, and to reduce that speed in various circumstances (such as when overtaking a pedestrian or bicycle, individually or in a group; when overtaking a stopped convoy; when passing a transportation vehicle loading or unloading people or children; when the road does not appear clear, or risky; when visibility is low, etc.).WEB,weblink Section 2 : Maîtrise de la vitesse. (Articles R413-17 à R413-19) - Légifrance, www.legifrance.gouv.fr, If drivers do not control their speed, or do not reduce it in such cases, they can be penalized. Other qualifying conditions include driving through fog, heavy rain, ice, snow, gravel,WEB,weblink On Gravel Roads, People Drive At Speed They Are Comfortable With, Regardless Of Posted Limit, 2010-10-13, "We found that people are driving at speeds based on their perceptions and existing conditions – regardless of the speed limit," said Dissanayake, who also is a faculty member with Kansas State University, K-State's University Transportation Center...when it came to speed limits, and the actual speeds are driven, the difference was not significant between {{cvt, 35, mph, and {{cvt|55|mph}} roads. An example is the gravel roadways in Johnson County and Miami County. The study found that though two-speed limits exist, the driving characteristics were the same. While Johnson County's speed limit is {{cvt|35|mph}} and posted, the average actual speed of {{cvt|37.5|mph}} was higher than the average actual speed of {{cvt|35.8|mph}} in Miami County, where the speed limit is {{cvt|55|mph}} and not posted.}} WEB,weblink Leeper v. Nelson, 139 Cal. App. 2d 65, 1956-02-06, Official California Appellate Reports (2nd Series Vol. 139, p. 65), 2013-07-27, The operator of an automobile is bound to anticipate that he may meet persons or vehicles at any point of the street, and he must in order to avoid a charge of negligence, keep a proper lookout for them and keep his machine under such control as will enable him to avoid a collision with another automobile driven with care and caution as a reasonably prudent person would do under similar conditions., See Huetter v. Andrews, 91 Cal. App. 2d 142, Berlin v. Violett, 129 Cal.App. 337, Reaugh v. Cudahy Packing Co., 189 Cal. 335, and Official Reports Opinions OnlineIn the United States, this requirement is referred to as the basic rule,WEB,weblink An Analysis of Speeding-Related Crashes:Definitions and the Effects of Road Environments, February 2009, U.S. Department of Transportation, National Highway Traffic Safety Administration, 2010-04-25, Appendix: The basic rules governing the speed of vehicles in Kansas, Kentucky, Maryland, Montana, North Carolina, and Wisconsin., as outlined by US federal government law (49 CFR 392.14WEB,weblink 49 CFR 392.14 - Hazardous conditions; extreme caution., LII / Legal Information Institute, ), which applies in all states as permitted under the commerce clause and due process clause.WEB,weblink State v. Stanko, Supreme Court of Montana, 1998, BOOK, Commercial Driver License Manual 2005, Section 2 – Driving Safely,weblinkweblink 2-15, 2-19, 2-26, 13-1, July 2014, United States Department of Transportation, [pg 2-15] 2.6.4 – Speed and Distance Ahead: You should always be able to stop within the distance you can see ahead. Fog, rain, or other conditions may require that you slow down to be able to stop in the distance you can see. ... [pg 2-19] 2.8.3 – Drivers Who Are Hazards: Vehicles may be partly hidden by blind intersections or alleys. If you only can see the rear or front end of a vehicle but not the driver, then he or she can't see you. Be alert because he/she may back out or enter into your lane. Always be prepared to stop. ... [pg 2-26] 2.11.4 – Vehicle Factors: Headlights. At night your headlights will usually be the main source of light for you to see by and for others to see you. You can't see nearly as much with your headlights as you see in the daytime. With low beams, you can see ahead about 250 feet and with high beams about 350-500 feet. You must adjust your speed to keep your stopping distance within your sight distance. This means going slowly enough to be able to stop within the range of your headlights. ... [pg 13-1] 13.1.2 – Intersections As you approach an intersection: Check traffic thoroughly in all directions. Decelerate gently. Brake smoothly and, if necessary, change gears. If necessary, come to a complete stop (no coasting) behind any stop signs, signals, sidewalks, or stop lines maintaining a safe gap behind any vehicle in front of you. Your vehicle must not roll forward or backward. When driving through an intersection: Check traffic thoroughly in all directions. Decelerate and yield to any pedestrians and traffic in the intersection. Do not change lanes while proceeding through the intersection. Keep your hands on the wheel., The basic speed law is almost always supplemented by specific maximum or minimum limits but applies regardless. In California, for instance, Vehicle Code section 22350 states that "No person shall drive a vehicle upon a highway at speed greater than is reasonable... and in no event at a speed which endangers the safety of persons or property".WEB,weblink California Vehicle Code section 22350: Basic Speed Law, No person shall drive a vehicle upon a highway at 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., 1963-09-20, 2010-04-25, California Department of Motor Vehicles, 2010-05-05,weblink" title="web.archive.org/web/20100505015126weblink">weblink dead, The reasonable speed may be different than the posted speed limit. Basic rule speed laws are statutory reinforcements of the centuries-old common law negligence doctrine as specifically applied to vehicular speed.WEB,weblink Reaugh v. Cudahy Packing Co., 189 Cal. 335, 1922-07-27, Official California Reports, Vol. 189, p. 335, (California Supreme Court reporter), 2013-07-27, This is but a reiteration of the rule, in statutory form, which has always been in force without regard to a statutory promulgation to the effect that drivers or operators of vehicles, and more particularly motor vehicles, must be specially watchful in anticipation of the presence of others at places where other vehicles are constantly passing, and where men, women, and children are liable to be crossing, such as corners at the intersections of streets or other similar places or situations where people are likely to fail to observe an approaching automobile., Citations for violations of the basic speed law without a crashWEB,weblink TEMECULA: Inquiries prompt new speed survey, 2015-08-13, have sometimes been ruled unfairly vague or arbitrary, hence a violation of the due process of law, at least in the State of Montana.WEB,weblink FindLaw's Supreme Court of Montana case and opinions, Findlaw, Even within states, differing jurisdictions (counties and cities) choose to prosecute similar cases with differing approaches.WEB,weblink 4 ways Virginia Reckless Driving charges are handled differently in Fairfax County, Arlington, Alexandria, and Stafford, Vincenzes, Brent, 2015-04-21, 2015-04-24,weblink" title="web.archive.org/web/20150424000543weblink">weblink dead,

Excessive speed

Consequential results of basic law violations are often categorized as excessive speed crashes; for example, the leading cause of crashes on German autobahns in 2012 fell into that category: 6,587 so-called "speed related" crashes claimed the lives of 179 people, which represented almost half (46.3%) of 387 autobahn fatalities in 2012.WEB, Unfallentwicklung auf deutschen Straßen 2012 (Accident trends on German roads 2012), 2013-07-10,weblink Statistisches Bundesamt (Federal Statistics Office), (Seite 19) Mit 29 Getöteten je 1 000 Unfälle mit Personenschaden ist das Todesrisiko auf Landstraßen fünfmal höher als auf Innerortsstraßen und auch höher als auf Autobahnen, auf denen 22 Personen je 1000 Unfälle starben. Ein Grund für das wesentlich höhere Risiko auf Landstraßen und Autobahnen ist, dass hier wesentlich schneller gefahren wird als auf Innerortsstraßen und dadurch die Unfallschwere steigt... (Seite 20) Hauptunfallursache auf Autobahnen ist die "nicht angepasste Geschwindigkeit." Im Jahr 2012 waren mehr als ein Drittel aller Unfälle mit Personenschaden auf Autobahnen Unfälle, bei denen mindestens einem Beteiligten dieses Fehlverhalten zur Last gelegt wurde. Bei insgesamt 6 587 sogenannten Geschwindigkeitsunfällen kamen 179 Menschen zu Tode, das heißt nahezu die Hälfte (46,3 %) aller Getöteten auf Autobahnen... (Seite 20) Hierbei ist allerdings zu berücksichtigen, dass die Unfallursache "nicht angepasste Geschwindigkeit" häufig nicht bedeutet, dass die zulässige Höchstgeschwindigkeit überschritten worden ist. "Nicht angepasste Geschwindigkeit" wird von der Polizei bei einem Unfall auch dann als Ursache erfasst, wenn ein Beteiligter für die vorliegenden Straßen- oder Witterungsverhältnisse zu schnell gefahren ist., 2013-09-23, www.destatis.de, PDF, However, "excessive speed" does not necessarily mean the speed limit was exceeded, rather that police determined at least one party traveled too fast for existing conditions.WEB,weblink A 95: Polizei geschockt über "immenses Tempo" [Translation: A 95: Police Shocked At High Speed], 2013-08-05, Merkur Online [The Mercury online version], 2013-09-29, den stellvertretenden Kommandanten der Feuerwehr aus Hohenschäftlarn (Kreis München), Daniel Buck... war mit seinen Kollegen einer der ersten an der Unfallstelle, an der ein Porschefahrer (51) so schnell in den Toyota einer 67-jährigen Weilheimerin bretterte, dass sich ihr Auto mehrmals überschlug. Die Frau musste noch vor Ort reanimiert werden, starb jedoch später im Krankenhaus. Die beiden Männer im Porsche kamen mit leichten Verletzungen davon... Auf Höhe des Dreiecks Starnberg verlor er auf der linken Spur die Kontrolle über sein Auto. Er kam ins Schleudern, schoss rechts über einen Grünstreifen und kam auf dem Zubringer aus Starnberg wieder auf die Fahrbahn. Dort rammte er die 67-jährige Weilheimerin in ihrem Toyota... Zeugen vor Ort schätzen, dass der Sportwagen mit rund 300 Kilometer pro Stunde unterwegs war... Ein Zeuge hatte seinen Tempomat auf 140 Stundenkilometer eingestellt und war von dem Sportwagen überholt worden. "Er schätzt, der Porsche war doppelt so schnell," sagt Buck. Und: "...Schneller wie 160 Kilometer pro Stunde ist hier absolut unangemessen.". [Translation: deputy commander of the fire brigade from Hohenschaeftlarn county (Munich), Daniel Buck...was one of the first with his colleagues at the accident site where a Porsche driver (age 51) bashed into the Toyota driven by a 67-year-old (Weilheim in Oberbayern]] resident, rolling her car over several times. The woman had to be resuscitated on site but died later in hospital. The two men in the Porsche escaped with minor injuries... At the peak of the Starnberg interchange in the left lane, he lost control of his car. He went into a skid, shot right through a grass strip to ram the 67-year-old Weilheimer resident in her Toyota... Witnesses on site estimated that the sports car was traveling about 300 kilometers per hour... One witness had his cruise control set at 140 kilometers per hour and was overtaken by the sports car. "He estimates the Porsche was twice as fast," says Buck. And: "This is simply irresponsible; even as fast as 160 kilometers per hour is inappropriate. "], NEWS,weblink Autobahn Pileup: 52-Car German Crash Kills 3 (VIDEO), 2011-11-19, Huffington Post, Examples of conditions where drivers may find themselves driving too fast include wet roadways (due to rain, snow, or ice), reduced visibility (due to fogNEWS, Kennedy, Maev, 'All you could hear was cars crashing': 120-car pile-up on Sheppey bridge,weblink The Guardian, 2013-09-06, or "white out" snowWEB, Girl killed, 138 cars involved in two massive pileups, Fox 19, 2013-01-21,weblink 2013-11-06,weblink" title="web.archive.org/web/20131109151401weblink">weblink dead, 2013-11-09, ), uneven roads, construction zones,WEB,weblink Detectives: Excessive Speed Factor In 422 Crash Death, 2013-07-10, The Post, 2013-11-06, dead, 2015-04-02,weblink" title="web.archive.org/web/20150402142331weblink">weblink curves,WEB,weblink [The teenage driver] lost control of the vehicle on a "curvy portion" of Sheed Road in Colerain Township and struck a parked Ford Titanium. The crash killed both passengers, [the driver] was traveling in excess of the posted {{cvt, 35, mph, speed limit to "catch up to a new model Audi R8 to get a better look at this costly vehicle"|title=Kyle Stein charged in Colerain Twp. crash that killed Rachel McGrath and Eric Moormann)|access-date=2013-11-06|archive-date=2013-11-07|archive-url=https://web.archive.org/web/20131107232727weblink|url-status=dead}} intersections, gravel roads,WEB,weblink Teen dies when fast Camaro crashes on gravel road in Spring Arbor Township, 2013-10-13, Detroit Free press, 2013-11-06, 2013-11-09,weblink" title="web.archive.org/web/20131109160338weblink">weblink dead, and heavy traffic.WEB, Too Fast for Conditions, Federal Motor Carrier Safety Administration (U.S. Department of Transportation),weblinkweblink 2013-11-05, dead, 2013-10-31, Per distance traveled, consequences of inappropriate speed are more frequent on lower speed, lower quality roads;WEB, the SUV was traveling between {{cvt, 62, mph, and {{cvt|70|mph}} on a {{cvt|35|mph}} road before it flipped into a pond in a dark, unlit area in Warren on March 10, [2013], killing the 19-year-old driver and five of the seven boys riding with her|url=http://www.omaha.com/news/no-sign-of-alcohol-for-teens-killed-in-oh-crash/article_62561445-eb6d-593e-9100-68330df9ddc9.html|title=No sign of alcohol for 6 teens killed in OH crash|date=4 April 2013 }} in the United States, for example, the "speeding fatality rate for local roads is three times that for Interstates".WEB, Speeding Counts on All Roads,weblink almost 50 percent of speeding-related fatalities occur on lower speed collector and local roads, which carry only 28.1 percent of the total vehicle miles traveled in the United States... the deadly consequences of speeding on local and collector roads becomes even more dramatic. The speeding fatality rate for local roads is three times that for Interstates, FHWA Safety (November 2000), 2013-10-14,weblink" title="web.archive.org/web/20131016055545weblink">weblink 2013-10-16, dead, For speed management, a distinction can exist between excess speed, which consists of driving in excess of the speed limit, and inappropriate speed, which consists of going too fast for the conditions.WEB,weblink Speed Enforcement, 2018, ec.europa.eu, 2020-12-29,

Maximum speed limits

(File:Highway speed limits europe with indicator colors.svg|thumb|Maximum speed limits by country in Europe in km/h (and their matching highway signpost color))Most countries have a legally assigned numerical maximum speed limit which applies on all roads when no other speed limit indications are present; 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.The speed limit is commonly set at or below the 85th percentile speed (the operating speed which no more than 15% of traffic exceeds),REPORT,weblink Speed Zoning Information, Institute of Transportation Engineers, 2009-09-17, 2004-03-22, 2010-07-05,weblink" title="web.archive.org/web/20100705040529weblink">weblink dead, MUTCD Sections 2B.13-16 #12WEB,weblink California Vehicle Code § 21400(b), The State of California, 2020-04-07, 2012-01-01, and in the US is frequently set {{cvt|4|to|8|mph|0}} below that speed.BOOK,weblink NCHRP Report 504 – Design Speed, Operating Speed, and Posted Speed Practices, National Academies Press, Washington, D.C., onlinepubs.trb.org, 2003-10-06, Transportation Research Board of the National Academies, Kay Fitzpatrick, Paul Carlson, Marcus A. Brewer, Mark D. Wooldridge, Shaw-Pin Miaou, Texas Transportation Institute, 0-309-08767-8, 0077-5614,weblink" title="web.archive.org/web/20141021111234weblink">weblink 2014-10-21, live, 88, 2009-09-16, Thus, if the 85th percentile operating speed as measured by a "Traffic and Engineering Survey" exceeds the design speed, legal protection is given to motorists traveling at such speeds (design speed is "based on conservative assumptions about the driver, the vehicle, and roadway characteristics").REPORT, Speed: Understanding Design, Operating, and Posted Speed, R.A., Krammes, K., Fitzpatrick, J.D., Blaschke, D.B., Fambro,weblink March 1996, Texas Transportation Institute, College Station, TX, Research Report 1465-1, The theory behind the 85th percentile rules is that, as a policy, most citizens should be deemed reasonable and prudent, and limits must be practical to enforce.WEB,weblink Establishing Speed Limits, azdot.gov, WEB, ESTABLISHING SPEED LIMITS: a case of "MAJORITY RULE",weblink Kansas Department of Transportation, However, there are some circumstances where motorists do not tend to process all the risks involved, and as a mass, choose a poor 85th percentile speed.{{Citation needed|date=October 2013}} This rule, in practice, is a process for "voting the speed limit" by driving, in contrast to delegating the speed limit to an engineering expert.Public opposition to speed limits being set by an authority, often arise because such agency has been viewed as abusing its power—such as by arbitrary indiscretion or by creating "speed traps." Because an expert can theoretically calculate a safer speed limit, than the populace's vote by driving, it is beneficial that local governments preserve strong public trust with their integrity in speed regulation. See A Policy on Geometric Design of Highways and Streets, AASHTO, 4th Ed., 2001; {{ISBN|1-56051-156-7}}WEB,weblink USLIMITS2 - Safety - Federal Highway Administration, safety.fhwa.dot.gov, The maximum speed permitted by statute, as posted, is normally based on ideal driving conditions and the basic speed rule always applies.WEB,weblink Riggs v. Gasser Motors, 22 Cal. App. 2d 636, Official California Appellate Reports (2nd Series, Vol. 22, p. 22), 1937-09-25, Violation of the statute generally raises a rebuttable presumption of negligence.WEB, 1958-07-17, Alarid v. Vanier, 50 Cal.2d 617,weblink Official California Reports, 2nd Series Vol. 50, p. 617 (California Supreme Court reporter), See Official California Reports onlineOn international European roads, speed should be taken into account during the design stage.{{Citation needed|date=October 2013}}{| class="wikitable"|+Maximum speed recommended by international European road design standards:!Road classification!60 km/h!80 km/h (50 mph)!100 km/h (60 mph)!120 km/h (75 mph)!140 km/h (85 mph)

				| 140

				| x

				| x

Minimum speed limits

Some roads also have minimum speed limits, usually where slow speeds can impede traffic flow or be dangerous.BOOK, Haney, James E., The relationships between speed, speed limits, and motor vehicle accidents. An annotated bibliography, 1974, The use of minimum speed limits is not as common as maximum speed limits, since the risks of speed are less common at lower speeds. In some jurisdictions, laws requiring a minimum speed are primarily centered around red-light districts or similar areas, where they may colloquially be referred to as kerb crawling laws.Hubbard, Phil. "Out of touch and out of time? The contemporary policing of sex work." Sex work now. Willan, 2013. 22-53.

Middle speed limits

Traffic rules limiting only middle speeds are rare. One such example exists on the ice roads in Estonia, where it is advised to avoid driving at the speed of {{cvt|25|-|40|kph}} as the vehicle may create resonance that may in turn induce the breaking of ice. This means that two sets of speeds are allowed: under {{cvt|25|kph}} and between {{cvt|40|-|70|kph}}.WEB,weblink Traffic rules on ice roads, Transport Administration of the Republic of Estonia,weblink 2021-01-26,

Variable speed limits

(File:Variable speed limit.jpg|thumb|upright|Example variable speed limit sign in the United States, in mph)(File:Digital speed limit sign.jpeg|thumbnail|upright|Digital speed limit sign for variable speed limits)In Germany, the first known experiments with variable speed limit signs took place in 1965 on a {{convert|30|km|adj=on}} stretch of German motorway, the A8 between Munich and the border city of Salzburg, Austria. Mechanically variable message signs could display speeds of 60, 80 and 100 km/h, as well as text indicating a "danger zone" or "accident". Personnel monitored traffic using video technology and manually controlled the signage.{{citation|url=http://elib.uni-stuttgart.de/opus/volltexte/2003/1468/pdf/Dissertation_Schick.pdf|title=(translation) "Influence of Traffic Control Systems on Freeway Capacity and Stability of Traffic Flow"; Original Title "Einfluss von Streckenbeeinflussungsanlagen auf de Kapazitaet von Autobahnabschnitten sowie die Stabilitaet des Verkehrsflusses"|publisher=University of Stuttgart|date=June 2003|author=Peter Schick|access-date=2010-10-16|page=20|doi=10.18419/opus-175|isbn=9783980821841|quote=(translation) "The first experiment was carried out in 1965 on a 30 km section of the A8 from Salzburg to Munich. The system consisted of mechanically variable message signs at a distance of 2 km, which could display speeds of 60, 80 and 100 km/h, and "danger zone" and "accident." Personnel monitored traffic using video technology and manually controlled the signage. Studies reported a decrease in traffic disruptions and breakdowns, harmonization of the velocity distribution and an increase in performance (Zackor 1972, see also Chapter 3.2.2)." German text: "Die erste linienhafte Beeinflussung des Verkehrs erfolgte im Jahr 1965 durch die Errichtung einer Wechselverkehrszeichenanlage auf einem 30 km langen Abschnitt der A8 auf der Richtungsfahrbahn Salzburg – München. Die Anlage bestand aus neben der Fahrbahn angebrachten mechanischen Wechselverkehrszeichen im Abstand von 2 km, die StVO-gerechte Zeichen für die Geschwindigkeitsbegrenzungen 60, 80 und 100 km/h sowie "Gefahrstelle" und "Unfall" anzeigen konnten (Abb. 2-1). Diese Zeichen wurden vom Betreiberpersonal, das mittels Videotechnologie eine Ãœbersicht über das Verkehrsgeschehen hatte, manuell geschaltet. Somit konnte erstmals auf einer Autobahn die Geschwindigkeit des Verkehrs beeinflusst sowie eine Unfallwarnung vorgenommen werden. Die ersten Erfahrungen und wissenschaftlichen Untersuchungen berichten von einer Abnahme der Störungen und Verkehrszusammenbrüche, einer Harmonisierung der Geschwindigkeitsverteilung sowie einer Steigerung der Leistungsfähigkeit (ZACKOR 1972, siehe auch Kapitel 3.2.2).}} Beginning in the 1970s, additional advanced traffic 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. In 2009, {{convert|1300|km}} of German motorways were equipped with such systems.{{citation|author=Ralf Schmahld|title=(translation) "20 years waiting in traffic jams"; Original Title "20 Jahre im Stau gestanden"|date=2009-08-06|url=http://www.turus.net/reise/4297-20-jahre-im-stau-gestanden.html?fontstyle=f-larger|publisher=Reise (Travel) magazine|quote=(translation) "A total of 1,300 kilometers of motorways now have traffic control systems for the harmonization of the traffic flow by speed limits and traffic warning, and the government expects to expand their use: 2500 km stretch of motorway could be controlled by these dynamic control systems." German text: "An insgesamt 1.300 Kilometern der Bundesautobahnen seien inzwischen Streckenbeeinflussungsanlagen zur Harmonisierung des Verkehrsablaufs durch Geschwindigkeitsbeschränkungen und Gefahrenwarnung installiert worden, teilt die Regierung weiter mit. 2.500 Kilometer Autobahnstrecke könnten mittels dynamischer Netzbeeinflussungsanlagen gesteuert werden"|access-date=2010-10-16}}In the United States, heavily traveled portions of the New Jersey Turnpike began using variable speed limit signs in combination with variable message signs in the late 1960s. Officials can adjust the speed limit according to weather, traffic conditions, and construction.{{citation|url=http://ntl.bts.gov/lib/jpodocs/briefing/12164.pdf|title=Examples of Variable Speed Limit Applications. Speed Management Workshop|date=2000-01-09|publisher=Transportation Research Board. 79th Annual Meeting|author=Mark Robinson|access-date=2010-10-17|quote="New Jersey. Status: Active (installed in the late 1960s). Objective: to provide early warning to motorists of slow traffic or hazardous road conditions. Setting: Urban/Rural - New Jersey Turnpike.|archive-date=2011-09-27|archive-url=https://web.archive.org/web/20110927115419weblink|url-status=dead}} More typically, variable speed limits are used on remote stretches of highway in the United States in areas with extreme changes in driving conditions.WEB,weblink Repository Notice - Bureau of Transportation Statistics, ntl.bts.gov, 2019-01-01, 2019-01-02,weblink dead, For example, variable limits were introduced in October 2010 on a {{convert|52|mi|adj=on}} stretch of Interstate 80 in Wyoming, replacing the winter season speed reduction from {{cvt|75|to|65|mph}} that had been in place since 2008.WEB,weblink WYDOT proposes to lower I-80 speed limit, 2008-09-29, The Wyoming Department of Transportation says it plans to impose a speed limit of {{cvt, 65, mph, on a {{cvt|52|mi}} stretch of the interstate between Laramie and Rawlins. The reduction from the existing speed limit of {{cvt|75|mph}} will take effect Oct. 15 and continue for six months. Also, WYDOT intends to install variable speed-limit signs on the same stretch of highway so the limit can be lowered further because of bad weather. The section is between the Quealy Dome Interchange, {{cvt|20|mi}} west of Laramie, and the Peterson Interchange, {{cvt|22|mi}} east of Rawlins, the agency said.|publisher=KSL-TV|access-date=2010-10-16}}WEB,weblink Wyoming seasonal speed limit will vary with conditions, 2010-10-15, ""When it’s all horizontal and drifts, it kills the visibility, and we have a horrible time trying to keep people on the road," Wyoming DOT engineer Tim McGary told Land Line Now on Sirius XM. McGary says this winter, truckers on I-80 will no longer see that {{cvt, 65, mph, seasonal speed limit between Laramie and Rawlins. Instead, the whole {{cvt|52|mi|adj=on}} stretch will have the electronic, variable speed limit signs that the DOT started installing last year. The variable signs allow the DOT to lower or raise the speed limit in {{cvt|5|mph}} increments depending on the weather conditions. And McGary says they work. The statistics are kind of showing that if we’re on top of things with our plow operators and troopers out there, and we get the speed limits reduced appropriately to the weather conditions, people are complying pretty well with that," McGary said. "Our crash rates have gone down, and we’re hoping to continue that trend.""|publisher=Land Line Magazine|access-date=2010-10-16|archive-date=2010-12-08|archive-url=https://web.archive.org/web/20101208192323weblink|url-status=dead}} This Variable Speed Limit system has been proven effective in terms of reducing crash frequency and road closures.CONFERENCE, Saha, P., Young, R., 2014-08-01, Weather-Based Safety Analysis for the Effectiveness of Rural Variable Speed Limit (VSL) Corridors, Transportation Research Board 93rd Annual Meeting, No. 14-2293,weblink dead, 2015-02-23,weblink" title="web.archive.org/web/20150223185553weblink">weblink REPORT, R. Young, V. Sabawat, P. Saha, Y. Sui, 2012-05-01, Rural Variable Speed Limits: Phase II, FHWA-WY-13/03F,weblink 2022-04-10, REPORT, Final Report: FHWA-WY-13/03F, May 2013,weblinkweblink" title="web.archive.org/web/20150522110130weblink">weblink 2015-05-22, dead, 2022-04-11, Similarly, Interstate 90 at Snoqualmie Pass and other mountain passes in Washington State have variable speed limits as to slow traffic in severe winter weather.WEB,weblink Managing Speed, January–February 2003, Public Roads, www.tfhrc.gov, 2008-07-06, 2008-09-21,weblink" title="web.archive.org/web/20080921132642weblink">weblink dead, As a response to fog-induced chain-reaction collisions involving 99 vehicles in 1990, a variable speed limit system covering {{convert|19|mi}} of Interstate 75 in Tennessee was implemented in fog-prone areas around the Hiwassee River.WEB,weblink Tennessee Low Visibility Warning System, Federal Highway Administration, 2010-10-17, The Georgia Department of Transportation installed variable speed limits on part of Interstate 285 around Atlanta in 2014. These speeds can be as low as {{cvt|35|mph}} but are generally set to {{cvt|35|mph}}.NEWS,weblink Moving speed limits on I-285, 2014-09-29, Atlanta Journal-Constitution, 2015-08-22, In 2016, the Oregon Department of Transportation installed a variable speed zone on a {{cvt|30|mi|adj=on}} stretch of Interstate 84 between Baker City and Ladd Canyon. The new electronic signs collect data regarding temperature, skid resistance, and average motorist speed to determine the most effective speed limit for the area before presenting the limit on the sign. This speed zone was scheduled to be activated November 2016.{{citation needed|date=January 2017}} Ohio established variable speed limits on three highways in 2017, then in 2019 granted the authority to the Ohio Department of Transportation to establish variable limits on any of its highways.{{orc|45|11|21}}(H)(3)NEWS,weblink ODOT: Variable speed limits only used to improve safety, Felton, Chad, 2019-04-05, The News-Herald (Ohio), The News-Herald, 2019-04-06, Willoughby, OH, In the United Kingdom, a variable speed limit was introduced on part of the M25 motorway in 1995, on the busiest {{convert|14|mi|adj=on}} section from junction 10 to 16. Initial results suggested savings in journey times, smoother-flowing traffic, and a decrease in the number of crashes; the scheme was made permanent in 1997.{{citation|url=http://www.nao.org.uk/publications/nao_reports/04-05/040515.pdf|title=Report (HC 15, 2004-05): Tackling congestion by making better use of England's motorways and trunk roads (Full Report)|publisher=National Audit Office|date=2004-11-26|access-date=2009-09-17|page=21|quote=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. Based on 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. 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.|archive-date=2008-10-30|archive-url=https://web.archive.org/web/20081030122101weblink|url-status=dead}} However, a 2004 National Audit Organisation 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. Since December 2008 the upgraded section of the M1 between the M25 and Luton has had the capability for variable speed limits.WEB,weblink M1 Junctions 6A to 10 Official Completion Ceremony, Highways Agency, dead,weblink" title="web.archive.org/web/20091115063727weblink">weblink 2009-11-15, In January 2010 temporary variable speed cameras on the M1 between J25 and J28 were made permanent.NEWS, M1 works speed cameras will stay, BBC News, 2010-01-03,weblink 2010-04-13, New Zealand introduced variable speed limits in February 2001. The first installation was on the Ngauranga Gorge section of the dual carriageway on State Highway 1, characterized by steep terrain, numerous bends, high traffic volumes, and a higher than average accident rate. The speed limit is normally {{cvt|80|kph}}.WEB,weblink Monitoring Incident and Travel Behaviour Through the Use of ATMS Architecture, 22–25 September 2002, initial results of a Transfund Research project being undertaken to evaluate the effectiveness of Variable Message Speed Signs (VMSS) within the Ngauranga Active Traffic Management System (NATMS). NATMS is an incident based system whose objective is to facilitate the passage of traffic through a very demanding section of state highway just north of Wellington... A unique feature of the NATMS is the use of VMSS which display a mandatory speed imposed by controllers in response to an incident or prevailing traffic conditions... In February 2001 Transit New Zealand (TNZ) commissioned the operation of the Ngauranga Active Traffic Management System (NATMS) on State Highway 1, north of Wellington, New Zealand. The NATMS covers a 4 km stretch of State Highway between Johnsonville and the SH1 / SH2 Interchange. The NATMS is the first system in New Zealand to use Automatic Incident Detection (AID) and was chosen because of the challenging driving conditions which are compounded by steep terrain, numerous bends and a high degree of weaving between lanes. This, in conjunction with a volume over 60,000 vehicles per day and an accident rate higher than the national average were contributing factors in the introduction of the NATMS., Andrew W Fergus and David J Turner (MWH NZ Ltd.), 2010-10-21, dead,weblink" title="web.archive.org/web/20100805191744weblink">weblink 2010-08-05, Austria undertook a short-term experiment in 2006, with a variable limit configuration that could increase statutory limits under the most favorable conditions, as well as reduce them. In June 2006, a stretch of motorway was configured with variable speed limits that could increase the general Austrian motorway limit of {{cvt|130|to|160|kph}}.WEB,weblink German: Ein Monat 'Tempo 160' auf der A10. English: A month of 'Tempo 160' on the A10, "German: Den 'Tempo 160-Test' auf der A10 bezeichnete Gorbach "allen Unkenrufen zum Trotz" als 'Meilenstein in der europäischen Verkehrspolitik'. Er betonte im Rahmen einer Pressekonferenz in Wien, dass mit Tempo 160 'nicht die Raser gefördert, sondern die Geschwindigkeit flexibilisiert' werden soll. English: '[The then Austrian Minister for Transportation Hubert] Gorbach said the 'Test Speed 160' on the A10 [motorway] was 'a milestone in European transport policy-despite all predictions to the contrary.' He said at a press conference in Vienna that a 160 limit 'does not promote speeding, but more flexible travel speeds'., 2010-04-16, 2011-07-18,weblink" title="web.archive.org/web/20110718111933weblink">weblink dead, Then Austrian Transport Minister Hubert Gorbach called the experiment "a milestone in European transport policy-despite all predictions to the contrary"; however, the experiment was discontinued.{{Citation needed|date=June 2019}}

Roads without speed limits

Just over half of the German autobahns have only an advisory speed limit (a Richtgeschwindigkeit), 15% have temporary speed limits due to weather or traffic conditions, and 33% have permanent speed limits, according to 2008 estimates.WEB,weblink SPEED Fact Sheet. German Autobahn: The Speed Limit Debate, European Transport Safety Council, February 2008, Currently, 52% of the German motorways do not have a speed limit, 15% have temporary speed limits due to weather or traffic conditions, and 33% have permanent speed limits. On unlimited sections, there is a 130 km/h recommendation., 2010-10-16,weblink" title="web.archive.org/web/20110106022926weblink">weblink 2011-01-06, dead, The advisory speed limit applies to any road in Germany outside of towns which is either a dual carriageway or features at least two lanes per direction, regardless of its classification (e.g. Autobahn, Federal Highway, State Road, etc.), unless there is a speed limit posted, although it is less common for non-autobahn roads to be unrestricted. All other roads in Germany outside of towns, regardless of classification, do have a general speed limit of {{cvt|100|kph}}, which is usually reduced to {{cvt|80|kph}} at Allée-streets (roads bordered by trees or bushes on one or both sites).WEB,weblink § 3 StVO: Speed, Bundesministerium der Justiz und für Verbraucherschutz, Diese Geschwindigkeitsbeschränkung gilt nicht [...] auf anderen Straßen mit Fahrbahnen für eine Richtung, die durch Mittelstreifen oder sonstige bauliche Einrichtungen getrennt sind. Sie gilt ferner nicht auf Straßen, die mindestens zwei durch Fahrstreifenbegrenzung (Zeichen 295) oder durch Leitlinien (Zeichen 340) markierte Fahrstreifen für jede Richtung haben., 2014-04-29, Travel speeds are not regularly monitored in Germany; however, a 2008 report noted that on the autobahn in Niemegk (between Leipzig and Berlin) "significantly more than 60% of road users exceed {{cvt|130|kph}} [and] more than 30% of motorists exceed {{cvt|150|kph}}".WEB,weblink Noise Action Plan of Gera 2008, Lärmaktionsplan 2008 der Stadt Gera, Die Berechnung basiert dabei auf der in Deutschland gültigen Richtgeschwindigkeit von 130 km/h. Die real gefahrene Geschwindigkeit auf "freigegebenen" Autobahnabschnitten liegt jedoch deutlich höher, wie das in Abb. 54 dargestellte Beispiel von der Bundesautobahn 9, A9 im Bereich Niemegk zeigt. Die V85 liegt teilweise bei über 170 km/h. Im Schnitt fahren deutlich über 60 % der Verkehrsteilnehmer schneller als 130 km/h. Mehr als 30 % der Verkehrsteilnehmer fahren im Schnitt schneller als 150 km/h (English translation) Calculations are based on the German recommended a speed of 130 km/h. Actual driving speeds on motorway sections is much higher, as shown in Figure 54, for example, the Bundesautobahn 9, A9 in Niemegk. The V85 [85th percentile speed] exceeds 170 km/h. On average, significantly more than 60% of road users exceed 130 km/h. More than 30% of motorists exceed 150 km/h., Measurements from the state of Brandenburg in 2006 showed average speeds of {{cvt|142|kph}} on a 6-lane section of autobahn in free-flowing conditions.WEB,weblink Auswirkungen eines allgemeinen Tempolimits auf Autobahnen im Land Brandenburg, October 2007, Brandenburg, 2010-12-04, (German)Auf einer 6-streifigen Autobahn ergibt sich für den Pkw-Verkehr im Mittel eine Geschwindigkeit von 142 km/h. (English)On clear stretches of 6-lane highway, cars average a speed of 142 km/h, 2012-09-07,weblink" title="web.archive.org/web/20120907215341weblink">weblink dead, Prior to German reunification in 1990, accident reduction programs in eastern German states were primarily focused on restrictive traffic regulation. Within two years of reunification, the availability of high-powered vehicles and a 54% increase in motorized traffic led to a doubling of annual traffic deaths,WEB,weblink East German Traffic Deaths Jumped Dramatically After Reunification; Researchers Cite Rapid Increase In Young, Unskilled Drivers, ScienceDaily, despite "interim arrangements [which] involved the continuation of the speed limit of {{cvt|100|kph}} on autobahns and of {{cvt|80|kph}} outside cities". 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 a decade of effort, while traffic regulations were conformed to western standards (e.g., {{cvt|130|kph}} freeway advisory limit, {{cvt|100|kph}} on other rural roads).WEB,weblink Traffic Safety - The German Experience after Reunification, Deutsche Gesellschaft für Technische Zusammenarbeit, German Society for Technical Cooperation, 2004-11-06, 2009-09-17, 2015-09-24,weblink" title="web.archive.org/web/20150924022657weblink">weblink dead, Many rural roads on the Isle of Man have no speed limits; a 2004 proposal to introduce general speed limits of {{cvt|60|mph}} and {{cvt|70|mph}} on Mountain Road, for safety reasons, was not pursued following consultation.WEB,weblink No All-Island Speed Limit, Isle of Man Guide, 2004-11-06, 2009-09-17, Measured travel speeds on the island are relatively low.WEB, Transport Implications of the Isle of Man Strategic Plan: Report, JMP Consulting, 2007-04-27,weblink 2010-09-26, 2011-01-25,weblink" title="web.archive.org/web/20110125021508weblink">weblink dead, The Indian states of Andhra Pradesh,WEB,weblink The Table of Maximum Speed Limits at a Glance, Maharashtra,WEB,weblink Data, 2020-12-29, and TelanganaWEB,weblink TRANSPORT DEPARTMENT GOVERNMENT OF TELANGANA - INDIA, www.transport.telangana.gov.in, also do not have speed limits by default.

Roads formerly without speed limits

Many roads without a maximum limit became permanently limited following the 1973 oil crisis. For example, Switzerland and Austria had no maximum restriction prior to 1973 on motorways and rural roads, but imposed a temporary {{cvt|100|kph}} maximum limit in response to higher fuel prices; the limit on motorways was increased to {{cvt|130|kph}} later in 1974.WEB,weblink The duties of the Swiss Federal Roads Office - ASTRA - Bundesamt, Outside of built-up areas: Prior to 1973: no restriction 1973: 100 km/h (provisional) 1977: 100 km/h (definitive) 1985: 80 km/h (trial) 1989: 80 km/h (definitive), national referendum on 26 November 1989 Motorways: Prior to 1973: no restriction 1973: 100 km/h (temporary), due to oil crisis 1974: 130 km/h (provisional) 1977: 130 km/h (definitive) 1985: 120 km/h (trial) 1989: 120 km/h (definitive), national referendum on 26 November 1989, 2009, 2010-10-26,weblink" title="web.archive.org/web/20110706221556weblink">weblink 2011-07-06, dead, WEB,weblink Seit 35 Jahren Tempolimit auf Autobahnen - oesterreich.ORF.at, oesv1.orf.at, WEB,weblink Willkommen | ÖAMTC, 2023-12-04, (File:MONTANA-PR.svg|thumb|Typical speed limit sign that one would see at the Montana state line from December 1995 to June 1999)Montana and Nevada were the last remaining U.S. states relying exclusively on the basic rule, without a specific, numeric rural speed limit before the National Maximum Speed Law of 1974.WEB,weblink The Development of a Speed Monitoring Program for Indiana (FHWA/IN/JTRP-98/19), Darren L. Jorgenson, Kumares C. Sinha, April 2000, 2010-09-26, Indiana Department of Transportation, CHAPTER 1: INTRODUCTION : 1.1 Background Information "Before 1974, Interstate highways through various states had different speed limits, except Montana and Nevada, which had none.", After the repeal of federal speed mandates in 1996, Montana was the only state to revert to the basic rule for daylight rural speed regulation. The Montana Supreme Court ruled that the basic rule was too vague to allow citation, prosecution, and conviction of a driver; concluding enforcement was a violation of the due process requirement of the Montana Constitution.WEB,weblink FindLaw's MT case and opinions, Findlaw, In response, Montana's legislature imposed a {{cvt|75|mph}} limit on rural freeways in 1999.WEB, 1999-05-28, Sky no longer the limit on 'Montanabahn',weblink 2022-04-18, Deseret News, Australia's Northern Territory had no rural speed limit until 2007, and again from 2014 to 2016. Sections of the Stuart Highway had no limits as part of an open speed limit trial.WEB, The need for speed on Stuart Highway, Australian Broadcasting Corporation (ABC), 2013-10-15,weblink 2020-12-07,

Method

Several methods exist to set up a speed limit:BOOK, Dell'Acqua, Gianluca,weblink Transport Infrastructure and Systems: Proceedings of the AIIT International Congress on Transport Infrastructure and Systems (Rome, Italy, 10-12 April 2017), Wegman, Fred, 2017-03-16, CRC Press, 978-1-315-28188-9, en,

• Engineering
• Harm minimization
• Economic optimization
• Expert system

For instance, the Injury Minimization (known as Safe System) method takes into account the crash types that are likely to occur, the impact forces that result, and the tolerance of the human body to withstand these forces to set speed limit. This method is used in countries such as the Netherlands and Sweden.WEB,weblink Methods and Practices for Setting Speed Limits: An Informational Report - Safety | Federal Highway Administration, safety.fhwa.dot.gov, The Operating speed method sets the maximum speed at or around the 85th percentile speed. This reduces the need to enforce the speed limit, but also allows drivers to fail to select the appropriate travel speed, when they misjudge the risk their environment induces. This is one method used in the United States of America.

Enforcement

File:Gatso Camera.jpg|thumb|upright|GatsoGatsoSpeed 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 monitoring, 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.{{Citation needed|date=June 2019}}In 2012, in the UK, 30% of drivers did not comply with speed limits.WEB,weblink Speed limits: A review of compliance, 2012, www.racfoundation.org, 2020-12-29, In Europe, between 2009 and 2012, 20% of European drivers have been fined for excessive speed.In 2012, in Europe, 62% of people supported the idea of setting up speed-limiting devices, with adequate tolerance levels in order to limit driver confusion. One efficient scheme consists of penalty points and charges for speeding slightly over the speed limit.Another possibility is to alter the roadway by implementing traffic calming measures, vehicle activated signs, or safety cameras.WEB,weblink Speed limit compliance and enforcement, 2014-02-27, niassembly.gov.uk, 2020-12-29, The city of Munich has adopted self-explaining roads: roadway widths, intersection controls, and crossing types have been harmonized so that drivers assume the speed limit without a posted sign.

Effectiveness

Compliance

Speed limits are more likely to be complied with if drivers have an expectation that the speed limits will be consistently enforced.JOURNAL, Bauernschuster, Stefan, Rekers, Ramona, 2022, Speed limit enforcement and road safety,weblink Journal of Public Economics, 210, 104663, 10.1016/j.jpubeco.2022.104663, 0047-2727, 10419/215026, free, To be effective and abided by, the speed limits need to be perceived as credible; they should be reasonable regarding factors such as how well the driver can see ahead and to the sides on a particular road. Speed limits also need to conform to road infrastructure, education, and enforcement activity.{{thumb|align=center|caption=Measure of effect of speed limit reduction from 90 km/h to 80 km/h, in July 2018, on the French network(ONISR, 28 janvier 2019)weblink{{dead link|date=December 2020}}|content={{Graph:Chart|type=line|width=300|x=June, July, August, September, October, November|xAxisAngle=-40|y3=,82.6,82.9,83.2,83.0,83.3|y2=87.0,82.6|y1=78.4,75.7,76.5,76.6,77.0,77.6|y4=90,80,,,,80|legend=|vAnnotatonsLine=July|vAnnotatonsLabel=Speed limit change|y3Title=Car speed (80 km/h speed limit)|y2Title=Car speed (90 km/h speed limit)|y1Title=HGV speed (80 km/h speed limit)|y4Title=Speed limit|yAxisMin=70|showValues=|xGrid=1|yGrid=1}}}}In the UK, in 2017, the average free flow speed for each vehicle type is correlated with the applicable speed limit for that road type and for motorways and national speed limit single carriageway roads, the average free flow speed is below the designated speed limit for each vehicle type, except motorcycles on motorways.WEB,weblink Vehicle Speed Compliance Statistics, 2017, assets.publishing.service.gov.uk, 2020-12-29, {{thumb|align=center|caption=Average free flow speed in UK in 2017|content={{Graph:Chart|width=600|type=rect|x=motorway, rural single carriage, 30 mph streets, 20 mph streets|y1=69,50,31,26|y2=69,50,31,25|y3=54,45,30,23|y4=61,48,30,24|y5=,47,29,21|y6=,47,27,23|y7=71,54,32,27|hAnnotatonsLine=20,30,50,70|hAnnotatonsLabel=20,30,50,70|legend=|y1Title=Cars|y2Title=Light Commercial Vehicles|y3Title=Articulated HGVs|y4Title=Rigid HGVs|y5Title=Short buses|y6Title=Long buses|y7Title=Motorcycles|showValues=}}}}

Relationship with crash frequency

A 1998 US Federal Highway Administration report cited a number of studies regarding the effects of reductions in speed limits and the observed changes in speeding, fatalities, injuries and property damage which followed.Table 3, J. Stuster and Z. Coffman, Synthesis of Safety Research Related to Speed and Speed Management, FHWA-RD-98-154, July 1998 Some states increase penalties for more serious offenses, by designating as reckless driving, speeds greatly exceeding the maximum limit.{{Citation needed|date=June 2019}}A 2018 OECD-ITF case study established a strong relationship between speed and crash frequency: when the mean speed decreases, the number of crashes and casualties decreases; to the contrary, when speed increases, the number of crashes and casualties increases. In no case was an increase in mean speed associated with a decrease in the number of crashes or casualties.WEB,weblink Speed crash risk, itf-oecd.org, 2020-12-29, {{thumb|align=center|caption=Relationship between change of mean speed and change of fatalitiesSource OECD-ITF|content={{Graph:Chart|type=line|showSymbols=true|linewidth=0|xAxisTitle=Mean speed changes (%)|yAxisTitle=Change of fatalities (%)|x=0,-7.8,-3.4,-5.6,-7.5,-8.0,-2.7,-7.7,2.6|y1=,,,,,,,,13.4|y2=,,-41.0,|y3=,,,-31.4,-25.5,-35.1,|y4=0|y5=,,,,,,-37.7,-14.3,|y6=,-18.2|yGrid=true|legend=|y1Title=Hungary (Speed limit change, non urban roads)|y2Title=Sweden (Speed limit change, non urban roads)|y3Title=France (Speed camera, non urban roads)|y4Title=Zero (No change has no effect)|y5Title=France (Speed camera, urban roads)|y6Title=Hungary (Speed limit change, urban roads)}}}}{| class="wikitable sortable"|+Results from lowering speed limits:! Country (year of research publication)! width=33% | Speed limit reduction! Reported change

	110	100	|Injury crashes declined by 19%

	5	20	|No significant change (4% increase relative to sites not changed)

	60	50	|Fatal crashes declined by 24%Injury crashes declined by 9%

	60	50	|Crashes declined by 20%

	110	90		14|kph}}Fatal crashes declined by 21%

	130	120		5|kph}}Fatal crashes declined by 12%

	60	40		4	0}}Crashes declined by 14%

	5	15	0}} decreases	No significant changes

	30	25			DATE=26 SEPTEMBER 2018, Radio New Zealand,

! Country (year)! Speed limit reduction! Reported change|France (2018/'19)

90	80		DATE=2018-07-31	LANGUAGE=FR	ARCHIVE-DATE=2019-06-09	URL-STATUS=DEAD, Five million euros have been spent on communication to explain the benefits of the speed reduction to {{cvt|80|kph}}, using various media, including television, radio, and social media (including 2 million euros for the "13 mètres" advertising movie explaining that speed reduction reduced braking distance by {{cvt|13|m}}).WEB,weblink 80 km/h, la com' à 5 millions d'euros, 2018-06-29, LExpress.fr, fr,	87.0	82.6	3.9	87.0	83.2|kph}} in September 2018.France to reach its historical best year for road fatalities, stopping a sequence of five years of increasing fatalities: Decrease of 10.7% (from 1,188 to 1,061) of fatalities saving 127 lives during the 2018 semester on rural (non motorway) network mostly impacted by the speed decrease Decrease of 5.3% at national level, including roads and semesters not impacted by the speed decrease, including, mainland and DOM but also COM/TOM oversea territories. Decrease of 5.8% (200 lives saved) in mainland, from 3,448 to 3,248 including roads and semesters not impacted by the speed decrease; Decrease of fatalities by 8 from 152 in 2017 to 144 in 2018 (-5%) in DOM oversea territories where national km/h speed limits applies, while an increase of 12 fatalities from 84 to 96 (+14%) occurs in COM/TOM oversea territories where national {{cvt|80|kph}} speed limit do not apply. Source: ONISR (National observatory).WEB,weblink Accidents, www.onisr.securite-routiere.interieur.gouv.fr, 2020-12-29, {{Dead link|date=January 2021|bot=InternetArchiveBot|fix-attempted=yes}} Speed excess were multiplied by 2.1 (2.4 for foreigners, 2.0 for French cars), with 260,000 additional new speed excess counted in July 2018 by the 1,100 speed cameras, with 400 act of vandalism on speed cameras during July 2018 A yellow vest revolt occurred vandalizing 80%NEWS,weblink Is your département planning to scrap France's 80km/h speed limit?, 2019-05-22, The Local France, PDF, 2020-12-29, of the around 4,700WEB,weblink Speed Camera Blackspots in France 2016, www.french-property.com, 2018-03-07, to 10,000 speed camera in 2018. In 2020, previous results are confirmed for the year 2019: mean car speed was reduced between 2.9 and 3.9 km/h, while mean speed of trucks was reduced by 2 km/h without speed limit change. By the same time, fatalities were reduce by 125 in the second semester 2018, by 84 in the first semester 2019, and 127 for the second semester 2019.WEB,weblink 80 km/h speed limit on rural single carriageways | French road safety observatory, www.onisr.securite-routiere.gouv.fr, However, results were not repeated in overseas territories.Final report considered speed limit change induced a {{cvt|3.5|kph}} speed decrease and saved 349 lives during the two years which last 20 monthsWEB,weblinkweblink dead, 2020-12-04, Presentation, www.onisr.securite-routiere.interieur.gouv.fr, 2020-12-29,

|Spain (2019)

100

90|kph}}|In Spain the year 2019 was the best year with the fewest people killed outside a built-up area.The number of people killed outside built-up areas decreased by 7.6% while the number of people killed on regular roads decreased by 9.5%. The number of people killed in cars outside built-up areas decrease by 16% from 598 to 503.WEB, Finaliza con 1.098 fallecidos, el mínimo histórico de víctimas mortales en carretera, 2019, www.dgt.es,weblink es,weblink" title="web.archive.org/web/20210126034152weblink">weblink 2021-01-26, dead, 2020-12-29,

{| class="wikitable sortable"|+Results from increasing speed limits:! Country! Speed limit increase! Reported change

	100	110	|Injury crashes increased by 25%

	5	20		60	80|kph}}

	120	130	|Effect as of yet unclear, more research needed

	55	65	|Fatal crashes increased by 21%

	55	65	|Fatal crashes increased by 22%Speeding increased by 48%

	55	65	|Fatalities increased by 15%Decrease or no effect in 12 states

	55	65	|Fatal crashes increased by 36%

	55	65	|Fatal and injury crashes increased significantly on rural freeways

	|No significant changes

	55	65			PUBLISHER=UNIVERSITY OF CINCINNATI	YEAR=1992, 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.,

	55	65	|Statewide fatality rates decreased 3–5% (Significant in 14 of 40 states)

	5	15	0}} increase	No significant changes

South Dakota increased its maximum speed limit from {{cvt|65|to|75|mph}} in 1996. Annual surveys of speed on South Dakota Interstate roads show that from 2000 to 2011, the average speed rose from {{cvt|71|to|74|mph}}.WEB,weblink South Dakota Speed Monitoring, South Dakota Department of Transportation, 2012, 2014-12-19, A 1999 study found that the U.S. states that increased speed limits in the wake of the repeal of federally mandated speed limits had a 15% increase in fatalities.JOURNAL, Farmer, Charles M., Retting, Richard A., Lund, Adrian K., 1999-09-01, Changes in motor vehicle occupant fatalities after repeal of the national maximum speed limit, Accident Analysis & Prevention, 31, 5, 537–543, 10.1016/S0001-4575(99)00010-X, 10440551, 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. The report stated that limited evidence suggests that speed limits have a positive effect on a system wide basis.{{harvtxt|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, thereby suggesting 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, the 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 {{cvt|1|mph}} change in speed, injury accidents will change by 5 percent (3 percent for every {{cvt|1|kph}}). However, limited evidence suggests the net effect of speed limits may be positive on a system wide basis.'Research in 1998 showed that the reduction of some {{cvt|30|mph}} United Kingdom speed limits to {{cvt|20|mph}} had achieved only a {{cvt|1|mph}} drop in speeds and no discernible reduction in accidents; {{cvt|20|mph}} speed limit zones, which use self-enforcing traffic calming, achieved average speed reductions of {{cvt|10|mph}}; child pedestrian accidents were reduced by 70% and child cyclist accidents by 48%.WEB,weblink Written Answers to Questions: Road Accidents, 2003-01-31, Hansard, House of Commons, 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 48 per cent. reduction in child cyclist accidents., 2010-04-23, 2010-04-24,weblink" title="web.archive.org/web/20100424050559weblink">weblink dead, Zones where speeds are set at 30 km/h (or 20 mph) are gaining popularityWEB,weblink Streetfilms | No Need for Speed: 20's Plenty for Us, as they are found to be effective at reducing crashes and increasing community cohesion.WEB,weblink 2011-11-27, Joshua Hart, Driven To Excess: A Study of Motor Vehicle Impacts on Three Streets in Bristol UK, dead, 2012-04-26,weblink" title="web.archive.org/web/20120426002544weblink">weblink Studies undertaken in conjunction with Australia's move from {{cvt|60|kph}} speed limits to {{cvt|50|kph}} in built-up areas found that the measure was effective in reducing speed and the frequency and severity of crashes.WEB,weblink A 50 km/h default urban speed limit for Australia?, Monash University Accident Research Centre, 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 the 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., A study of the impact of the replacement of {{cvt|60|kph}} with {{cvt|50|kph}} speed limits in New South Wales, Australia, showed only a {{cvt|0.5|kph|1}} drop in urban areas and a {{cvt|0.7|kph|1}} drop in rural areas. The report noted that widespread community compliance would require a combination of strategies including traffic calming treatments.WEB,weblink Evaluation of a 50 km/h Default Urban Speed Limit for Australia, Monash University Accident Research Centre, November 2001, 2012-09-15, The trial achieved reductions in average speeds of 1.5 to 2 km/h in some councils and a 7% reduction in the number of casualties and casualty crashes in the trial LGAs compared to the rest of the State., Information campaigns are also used by authorities to bolster support for speed limits, for example the "Speeding. No one thinks big of you." campaign in Australia in 2007.

Justification

Speed limits are set primarily to balance road traffic safety concerns with the effect on travel time and mobility. Speed limits are also sometimes used to reduce consumption of fuel or in response to environmental concerns (e.g. to reduce vehicle emissions or fuel use).WEB,weblink Current speed limit policies, European Commission, A speed limit is based on both safety and mobility considerations and increasingly also on environmental considerations., 2010-04-23, dead,weblink" title="web.archive.org/web/20130125011725weblink">weblink 2013-01-25, Some speed limits have also been initiated to reduce gas-oil imports during the 1973 oil crisis.WEB,weblink Nixon signs national speed limit into law, history.com, 2019-11-06,

Road traffic safety

{{See also|Road traffic safety}}File:Ruta Panamericana Buenos Aires Florida.jpg|thumb|The Pan-American HighwayPan-American HighwayAccording to a 2004 report from the World Health Organization, 22% of all injury mortality worldwide was from road traffic injuries in 2002,{{harvtxt|World Health Organization|2004}} p. 34 fig 2.1 and without "increased efforts and new initiatives" casualty rates would increase by 65% between 2000 and 2020.{{harvtxt|World Health Organization|2004}} p. 3 The report identified that the speed of vehicles was "at the core of the problem",{{harvtxt|World Health Organization|2004}} p. 76 and recommended that speed limits be set appropriately for the road function and design, along with the implementation of physical measures related to the road and the vehicle, and increased effective enforcement by the police.{{harvtxt|World Health Organization|2004}} p. 127 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).NEWS,weblink UN raises child accidents alarm, BBC News, 2008-12-10, 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.{{harvtxt|Federal Highway Administration|1998|p=2}} 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;{{harvtxt|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' when severity is taken into account, the risk is lowest for those traveling at or below the median speed and "increases exponentially for motorists travelling much faster".{{harvtxt|Federal Highway Administration|1998|p=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'File:One-lane chicane 1.jpg|thumb|Traffic calmingTraffic calmingIt 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,REPORT,weblink Synthesis of Safety Research Related to Speed and Speed Limits, Federal Highway Administration, 2009-09-17, 1998, rising much faster than kinetic energy.{{Citation needed|date=June 2019}}

Kinetic energy:

E_mathrm{kin} = frac{1}{2} m v^2

Braking distance during danger

s_mathrm{GefahrBrems} approx frac{1}{2} cdot left( frac{v^2}{10^2} right) {{Graph:Chart|type=line|width=200|height=200|hAnnotatonsLine= 1|hAnnotatonsLabel=100%|vAnnotatonsLine=0|vAnnotatonsLabel=0|x=-5,-4,-3,-2,-1,0,1,2,3,4,5|y1Title=30 mph|y1=.22,.36,.51,.66,.83,1,1.18,1.38,1.59,1.81,2.04|y2Title=50 mph|y2=.48,.58,.68,.79,.89,1,1.11,1.22,1.34,1.46,1.58|y3Title=80 mph|y3=.75,.8,.85,.9,.95,1,1.05,1.1,1.16,1.21,1.27|legend=Expected fatal crash changes by modification in average operated speed|xGrid=1|yGrid=1|xAxisTitle=Change in operated speed (mph)|yAxisTitle=Fatal crash factor|yAxisFormat=%}}Source: Reproduced from AASHTO (2010)WEB,weblink Countermeasures guide, www.onisr.securite-routiere.gouv.fr, 2020-12-29, {{Dead link|date=January 2021|bot=InternetArchiveBot|fix-attempted=yes}}Typically motorways have higher speed limits than conventional roads because motorways have features which decrease the likelihood of collisions and the severity of impacts. For example, motorways separate opposing traffic and crossing traffic, employ traffic barriers, and prohibit the most vulnerable users such as pedestrians and bicyclists. Germany's crash experience illustrates the relative effectiveness of these strategies on crash severity: on autobahns 22 people died per 1,000 injury crashes, a lower rate than the 29 deaths per 1,000 injury accidents on conventional rural roads. However, the rural risk is five times higher than on urban roads; speeds are higher on rural roads and autobahns than urban roads, increasing the severity potential of a crash. The net effect of speed, crash probability, and impact mitigation strategies may be measured by the rate of deaths per billion-travel-kilometres: the autobahn fatality rate is 2 deaths per billion-travel-kilometres, lower than either the 8.7 rates on rural roads or the 5.3 rate in urban areas. The overall national fatality rate was 5.6, slightly higher than urban rate and more than twice that of autobahns.WEB, Traffic and Accident Data: Summary Statistics - Germany, December 2012,weblink Bundesanstalt für Straßenwesen [Federal Highway Research Institute], 2013-09-10,weblink" title="web.archive.org/web/20130626165800weblink">weblink 2013-06-26, dead, 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 about 55% of all speeding-related crashes when fatal listed "exceeding posted speed limits" among their crash factors, and 45% had "driving too fast for conditions" among their crash factors. However, the authors of the report did not attempt to determine whether the factors were a crash cause, contributor, or an unrelated factor.REPORT,weblink An Analysis of Speeding-Related Crashes:Definitions and the Effects of Road Environments, Liu, Cejun, Chen, Chou-Lin, 2009, National Highway Traffic Safety Administration, Furthermore, separate research finds that only 1.6% of crashes are caused by drivers that exceed the posted speed limit.WEB,weblink State Reports Show Speeding Not a Significant Cause of Accidents, www.thenewspaper.com, Finally, exceeding the posted limit may not be a remarkable factor in the crash analysis as there are roadways where virtually all motorists are in technical violation of the law.WEB, Scott, Friedman,weblink Nearly Everyone Speeds on Dallas Co. Freeways, NBC 5 Dallas-Fort Worth, 2012-02-07, 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 US as "a selected speed used to determine the various geometric design features of the roadway".REPORT, Design Speed, Operating Speed, and Posted Speed Practices,weblink Report 504, National Cooperative Highway Research Program, However, traffic engineers recognize that "operating speeds and even posted speed limits can be higher than design speeds without necessarily compromising safety"REPORT,weblink Design Speed, Operating Speed, and Posted Speed Practices, Report 504, National Cooperative Highway Research Program, 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 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)., since design speed is "based on conservative assumptions about driver, vehicle and roadway characteristics".Vision Zero, which envision reducing road fatalities and serious injuries to zero by 2020, suggests the following "possible long term maximum travel speeds related to the infrastructure, given best practice in vehicle design and 100% restraint use":WEB,weblink Table 1. Possible long term maximum travel speeds related to the infrastructure, given best practice in vehicle design and 100% restraint use..., Vision Zero - An ethical approach to safety and mobility, Claes Tingvall, Narelle Haworth, amp, {| class="wikitable"|+Possible maximum travel speeds:! Type of infrastructure and traffic! Possible travel speed (km/h)

	30|kph}}

	50|kph}}

	QUOTE="EUROPE'S TOP ROAD SAFETY AGENCY WARNED YESTERDAY THAT THE SPEED LIMIT ON OUR KILLER RURAL ROADS IS TOO HIGH AND SHOULD BE SLASHED BY A THIRD...THE GENERAL SPEED LIMIT OF 100 KM/H ON MAIN RURAL ROADS WHICH DO NOT HAVE DIVIDING CRASH BARRIERS SHOULD BE CUT TO 70 KM/H OR LESS, AN OFFICIAL REPORT RECOMMENDED YESTERDAY."	DATE=2010-10-13, Irish Independent, ||{{cvt|70|kph}}

	100|kph}}+

"Roads with no possibility of a side impact or frontal impact" are sometimes designated as Type 1 (motorways/freeways/Autobahns), Type 2 ("2+2 roads"), or Type 3 ("2+1 roads").WEB,weblink NRA New Divided Road Types: Type 2 and Type 3 Dual-carriageways, (Ireland) National Road Authority, Type 2 Dual Carriageway: A divided all-purpose road with two lanes in each direction Type 3 Dual Carriageway: A divided all purpose road with two lanes in one direction of travel and one lane in the other direction. the two-lane section, which provides the overtaking opportunity, alternates with a one-lane section at intervals, 2010-11-22, dead,weblink" title="web.archive.org/web/20110103164737weblink">weblink 2011-01-03, These roadways have crash barriers separating opposing traffic, limited access, grade separation and prohibitions on slower and more vulnerable road users. Undivided rural roads can be quite dangerous even with speed limits that appear low by comparison. For example, in 2011, Germany's {{cvt|100|kph}}-limited rural roads had a fatality rate of 8.7 deaths per billion travel-km, over four times higher than the autobahn rate of 2 deaths. Autobahns accounted for 31% of German road travel in 2011, but just 11% (453 of 4,009) of traffic deaths.In 2018, an IRTAD WG published a document which recommended maximum speed limits, taking into account forces the human body can tolerate and survive.{| class="wikitable"|+Towards a safe system, reasonable speed limits (IRTAD WG approach, 2018):! Type of infrastructure and traffic! Possible travel speed (km/h)

	30	40|kph}}

	50|kph}}

	70	80|kph}}

Source IRTAD, 2018

Fuel efficiency

Fuel efficiency sometimes affects speed limit selection. The United States instituted a National Maximum Speed Law of {{cvt|55|mph}}, as part of the Emergency Highway Energy Conservation Act, in response to the 1973 oil crisis to reduce fuel consumption.WEB,weblink Nevada brief in Nevada v. Skinner, dead,weblink" title="web.archive.org/web/20101128193331weblink">weblink 2010-11-28, 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.WEB, The High Cost of the 55 MPH Speed Limit, 2007-04-19, Copulos, Milton R.,weblink The Heritage Foundation, 1986-09-09, dead,weblink" title="web.archive.org/web/20070510160215weblink">weblink 2007-05-10, In 2009, the American Trucking Associations called for a {{cvt|65|mph}} speed limit, and also national fuel economy standards, claiming that the lower speed limit was not effective at saving fuel.WEB,weblink Trucking Industry Asks Congress for National 65 mph Speed Limit, 2009-01-27, Environment News Service, 2009-02-08, 2009-01-31,weblink" title="web.archive.org/web/20090131051033weblink">weblink dead,

Environmental considerations

Speed limits can also be used to improve local air quality issues or other factors affecting environmental qualityJOURNAL, Int Panis L, etal, 2011, PM, NOX and CO2 emission reductions from speed management policies in Europe, Transport Policy, 18, 1, 32–37, 10.1016/j.tranpol.2010.05.005, (e.g. the "environmental speed limits" in an area of Texas).WEB,weblink Vehicular Speed-Limit Reduction, Texas Commission on Environmental Quality, 2002, 2010-04-13, dead,weblink" title="web.archive.org/web/20100126004805weblink">weblink 2010-01-26, The European Union is also increasingly using speed limits as in response to environmental concerns.European studies have stated that, whereas the effects of specific speed reduction schemes on particulate emissions from trucks are ambiguous, lower maximums speed for trucks consistently result in lower emissions of CO2 and better fuel efficiency.

Advocacy

Speed limits, and especially some of the methods used to attempt to enforce them, have always been controversial. A variety of organisations and individuals either oppose or support the use of speed limits and their enforcement.

Opposition

Speed limits and their enforcement have been opposed by various groups and for various reasons since their inception. In the UK, the Motorists' Mutual Association (est. 1905) was formed initially to warn members about speed traps; the organisation would go on to become the AA.WEB,weblink AA History, The story of the AA since 1905, "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.", The Automobile Association, 2008-10-26, More recently, 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 including the Association of British Drivers, and the German Auto Club (ADAC).WEB,weblink Autobahn-Temporegelung, German:Der ADAC hält ein allgemeines Tempolimit auf Autobahnen für nicht erforderlich... Ein Zusammenhang zwischen generellem Tempolimit und dem Sicherheitsniveau auf Autobahnen ist nicht feststellbar. Die Zahl der Getöteten auf Autobahnen pro einer Milliarde Fahrzeugkilometer liegt in Deutschland bei 2,2, mit fallender Tendenz. Zahlreiche Länder mit genereller Geschwindigkeitsbeschränkung schneiden schlechter ab, z.B. Dänemark, Belgien, Österreich, USA. In Österreich, wo ein generelles Tempolimit von 130 km/h gilt, ist die Getötetenrate auf Autobahnen etwa 1,5-mal höher als in Deutschland. English: ADAC holds a general speed limit on motorways to be unnecessary... A connection between general speed limit on highways and safety is undetectable. The number of deaths on motorways per 1 billion vehicle-kilometers in Germany is 2.2 with a falling trend. Many countries fare worse with a general speed limit than Germany (e.g. Denmark, Belgium, Austria, USA). In Austria, where speed is generally 130, the death rate on motorways is about 1.5 times higher, 2010-11-22, 2015-01-01,weblink dead, , Press Release, June 2010.Arguments used by those advocating a relaxation of speed limits or their removal include:

• A 1994 peer-reviewed paper by Charles A. Lave et al. titled "Did the 65 mph Speed Limit Save Lives?" which states as evidence that a higher speed limit may create a positive shift in traffic to designated safer roads.JOURNAL, Lave, Charles, Elias, Patrick,weblink Did the 65 mph speed limit save lives?, Elsevier, Accident Analysis & Prevention, February 1994, 26, 1, 49–62, 10.1016/0001-4575(94)90068-X, 8110357, 21929276, 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], 2010-04-20, dead,weblink" title="web.archive.org/web/20110512173343weblink">weblink 2011-05-12,
• A 1998 report in the Wall Street Journal titled "Highways are safe at any speed", stating when speed limits are set artificially low, tailgating, weaving and speed variance (the problem of some cars traveling significantly faster than others) make roads less safe.WEB,weblink Highways Are Safe at Any Speed, Eric, Peters, Wall Street Journal, 1998-11-24, 2012-02-17, 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, dead,weblink" title="web.archive.org/web/20120412003252weblink">weblink 2012-04-12,

• A 2007 ePetition to the UK government calling for speed cameras to be scrapped on the basis that the benefits were exaggerated and that they may actually increase casualty levels, conducted by Safe Speed, a UK advocacy organisation campaigning for higher speed limits, which received over 25,000 signatures.WEB,weblink Speed limits, Safe Speed, 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 / 50 km/h on a UK "A" road suitable for 60 mph / 100 km/h. 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 / 90 km/h the crash risk will increase", WEB,weblink Welcome to Safe Speed, Smith, Paul, 2007-03-14, Safe Speed, 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.", NEWS,weblinkweblink 2022-01-12, subscription, live, Scrap speed cameras now, Smith, Paul, 2007-06-23, The Telegraph, 2010-04-17, London, {{cbignore}}
• A 2008 declaration by the German Automobile Manufacturer's Association calling general limits "patronizing",WEB, VDA opposes using speed limit to patronize the public: General Speed Limit Will Not Help with Climate Protection or Safety, March 2008, Verband der Automobilindustrie,weblink "A general speed limit on Germany's autobahns will not offer additional benefits in terms of climate protection or driving safety," said VDA Managing Director Dr. Kunibert Schmidt... "Much more important than the mantra-like repetition of old demands are measures designed to prevent motorists from driving at speeds that are not in line with weather conditions and the flow of the surrounding traffic - the leading cause of motor vehicle accidents.", 2011-07-02, 2011-09-28,weblink" title="web.archive.org/web/20110928221757weblink">weblink dead, arguing instead for variable speed limits. The Association also stated that "raising the speed limits in Denmark (in 2004 from {{cvt|110|to|130|kph}})WEB,weblink Higher speed limits reducing accidents on rural roads: Few accidents stem from cars overtaking, Nine years ago the speed limit on certain motorways was increased from 110 km/h to 130 km/h, and this resulted in fewer traffic fatalities on those stretches of road., 2014-02-22, 2014-02-21,weblink" title="web.archive.org/web/20140221105613weblink">weblink dead, WEB,weblink Socialists open up several highways to 130 km / h (S Ã¥bner for flere motorveje med 130 km/t), Carsten Thomsen, 2012-06-11, Socialists are now open to raising the speed limit to 130 km/h on several of the country's motorways. Previously, the party was strongly opposed when the Liberal government in 2005 raised the speed limit from 110 to 130 on several stretches. However, it has not resulted in increased fatalities. Which it has convinced the Socialists, says Transport Coordinator Rasmus Prehn. 'There might be places where you can raise the limit from 110 km/h to 130 km/h. There should be a detailed assessment of that. What is important is that people get a feeling that there is a correlation between how things are and how fast you can drive, says Rasmus Prehn. The number of fatalities last year was 220, which is the lowest since World War II. Only 12 were killed on motorways. (ORIGINAL DANISH: Socialdemokraterne Ã¥bner nu for at hæve fartgrænsen til 130 kilometers i timen pÃ¥ flere af landets motorvejsstrækninger. Partiet var ellers stærkt imod, da VK-regeringen i 2005 hævede fartgrænsen fra 110 til 130 pÃ¥ en lang række strækninger. Men det har ikke betydet flere dræbte i trafikken. Og det har overbevist Socialdemokraterne. trafikordfører Rasmus Prehn. Der kan godt være steder, hvor man kan hæve grænsen fra 110 km/t til 130 km/t. Det skal der en nærmere vurdering til. Men det, der er vigtigt, er, at folk fÃ¥r en oplevelse af, at der er en sammenhæng mellem hvordan forholdene er, og hvor hurtigt man mÃ¥ køre, siger Rasmus Prehn. Antallet af trafikdræbte var sidste Ã¥r 220. Det er det laveste siden Anden Verdenskrig. Kun 12 omkom pÃ¥ motorveje.), and Italy (2003 increase on six-lane highways from {{cvt|130|to|150|kph}}) had no negative impact on traffic safety. The number of accidental deaths even declined".WEB,weblink Fakten gegen ein generelles Tempolimit ("Facts Against A General Speed Limit"), 2007-03-31, Thus, Denmark in April 2004 increased its speed limit 110 km/h to 130 km/h on all highways. Italy enacted its 2003 speed limit on six-lane highways of 130 km/h to 150 km/h...Raising the speed limits in Denmark and Italy had no negative impact on traffic safety. The number of accidental deaths even declined over the year before the increase in the limit of -10% (Italy) or -15% (Denmark).(German) So hat Dänemark im April 2004 sein Tempolimit von 110 km/h auf 130 km/h auf allen Autobahnen heraufgesetzt. Italien setzte 2003 sein Tempolimit auf sechsspurigen Autobahnen von 130 km/h auf 150 km/h herauf. Auch die schwedische Regierung hat jetzt eine Anhebung des Tempolimits auf ausgewählten Streckenabschnitten wie auch auf vierspurigen Landstraßen beschlossen. ...Die Anhebung der Tempolimits in Dänemark und Italien hatten keinerlei negative Auswirkungen auf die Verkehrssicherheit. Die Zahl der Unfalltoten sank sogar gegenüber dem Jahr vor der Anhebung des Limits um –10 % (Italien) bzw. –15 %(Dänemark)., 2011-07-02,weblink" title="web.archive.org/web/20110928221832weblink">weblink September 28, 2011, dead,
• In a 2010 ADAC report, it was said that an autobahn speed limit was unnecessary because numerous countries with a general highway speed limit had worse safety records than Germany. However, more recent data show that Germany ranks in the lower middle field in a Europe-wide comparison regarding the number of fatalities per billion vehicle kilometers traveled on motorways.WEB, Infografik: Todesfälle auf Autobahnen im Europa-Vergleich, Statista Infografiken,weblink 2021-06-06, de, ETSC considers that those data are not comparable, because estimations of the number of kilometers traveled are not estimated the same way in different countries.REPORT, RANKING EU PROGRESS ON IMPROVING MOTORWAY SAFETY: PIN Flash Report 28, March 2015,weblink

Support

Various other advocacy groups press for stricter limits and better enforcement. 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 titled "Murder most foul", which laid out in an emotional but detailed view of the situation as they saw it, calling for tighter speed limits.WEB,weblink Murder most foul, J.S.Dean, 2010-04-18, Historically, the Pedestrians' Association and the Automobile Association were described as "bitterly opposed" in the early years of United Kingdom motoring legislation.BOOK,weblink Criminal on the road, 102, 1964, Tavistock Publications, 2010-04-27, Moreover it has been the result of a 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 also shows that motoring law in 1903 and 1930 wa framed by legislators who knew little of the motor vehicle., 978-0-415-26416-7, More recently organisations such as RoadPeace, Twenty is Plenty, and Vision Zero have campaigned for lower speed limits in residential areas. In the United States, advocacy groups favoring stricter limits and better enforcement include the Advocates for Highway and Auto Safety, Insurance Institute for Highway Safety and the National Safety Council.

Signage

(File:Speed sign stack.jpg|thumb|A stack of rectangular speed limit signs in the United States)File:Zeichen 393 - Informationstafel an Grenzübergängen, StVO 1981 und 1992.svg|thumb|upright|German border crossing sign showing {{cvt|50|kph}} limit in built-up areas, {{cvt|100|kph}} in rural areas, but a legal advisory {{cvt|130|kph}} limit for the Autobahn (motorway), increasing liability in the case of an accident from driving fasterWEB, de,weblink Autobahnrichtgeschwindigkeitsverordnung, German Federal GovernmentGerman Federal Government Most countries worldwide measure speed limits in kilometres per hour, while the United Kingdom, United States, and several smaller countries measure speed limits in miles per hour instead. Signs in Samoa display both units simultaneously.There are two basic designs for speed limit signs: the Vienna Convention on Road Signs and Signals specifies a white or yellow circle with a red border, while the Manual on Uniform Traffic Control Devices (MUTCD) published by the United States Federal Highway Administration specifies a white rectangle with the legend SPEED LIMIT. Vienna-style speed limit signs originated in Europe and are used in most of the world, including many countries that otherwise follow the MUTCD. Variations on the MUTCD design are used in Canada, Guam, Liberia, Puerto Rico,BOOK, Manual de Señales de Tránsito para las Vías Públicas de Puerto Rico, Puerto Rico Department of Transportation and Public Works, 1979, 5,weblink PDF, es,weblink" title="web.archive.org/web/20190707044042weblink">weblink 2019-07-07, the mainland United States, the U.S. Virgin Islands. Australia also used a variation on the MUTCD design until the country metricated in 1974. The Central American Integration System (SICA) equivalent to the US MUTCD, specifies a variation on the MUTCD design as an option, though not widely used.WEB, Central American Integration System, 2000-01-01, Catálogo de Señales Manual SIECA 2000,weblink Catálogo de Señales Manual SIECA 2000, In the United States, Canada, Australia and Peru, speed limit signs are rectangular. In most of the United States, speed limit signs bear the words SPEED LIMIT above the numeric speed limit, as specified in the MUTCD. However, in Alaska and California, speed limits are often labeled MAXIMUM SPEED instead. In Oregon, most speed limit signs are simply labeled SPEED. Canada has similar signs bearing the legend MAXIMUM, which has a similar meaning in English and French, the country's two main languages. Peru uses a similar, reversed variation of the MUTCD order in which the words VELOCIDAD MAXIMA (speed limit) are placed below the numeric limit. Australia uses the same rectangular design, but inscribes the numeric speed limit within a red circle as in Vienna Convention signs.WEB,weblink Traffic Operations : Road Signs, 2002-08-23, Government of South Australia,weblink" title="web.archive.org/web/20090702210520weblink">weblink 2009-07-02, 2010-09-26, Most regulatory signs are rectangular with a black legend on a white background...[exceptions include] speed restriction signs (symbol enclosed in a red circle)", The MUTCD formerly specified an optional metric design that included the words SPEED LIMIT and the numeric limit inscribed within a black circle, though it was rarely used in the United States;WEB, Frequently Asked Questions - General Questions on the MUTCD, Manual on Uniform Traffic Control Devices, United States Department of Transportation, 2017-03-08, 2019-11-22,weblink this design is still occasionally found in Liberia.WEB, Image by mkanyala, Mapillary, 2017-09-11, 2019-04-21,weblink WEB, Image by mkanyala, Mapillary, 2017-09-11, 2019-04-21,weblink WEB, Image by mkanyala, Mapillary, 2017-09-11, 2019-04-21,weblink Speed limit signs of Mexico and Panama are square, unlike the United States.In the European Union, large signposts showing the national (maximum) speed limits of the respective country are usually erected immediately after border crossings, with a repeater sign some {{cvt|200|to|500|m}} after the first. 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.WEB, Information about the Speed Limit in force,weblink European Commission, EU Mobility and Transport, 2020-01-28, 2016-10-17, In Ontario, the type, location, and frequency of speed limit signs are covered by regulation 615 of the Ontario Highway Traffic Act.WEB, Regulation 615 of the H.T.A.,weblink E-laws Government Website, 2014-07-24, 2015-03-28,

Maximum speed limit

File:Zeichen 274-60 - Zulässige Höchstgeschwindigkeit, StVO 2017.svg|thumb|upright|Speed limit sign in Germany, showing a 60 km/h restriction in DIN 1451DIN 1451(File:Lépron-les-Vallées (Ardennes) city limit sign.JPG|thumb|In France towns and city signs imply the speed limit of an urban road, by application of the Vienna Convention. For this reason the 50 sign on the picture is just a rappel (continuance of an existing speed limit).)File:Hungary road sign C-033-50.svg|Speed limit sign for 50 km/h (Vienna Convention Sign C14, most of the world follows this pattern)File:UK traffic sign 670V50.svg|UK sign for 50 mphFile:Australia road sign R4-1 (50).svg|Standard speed limit sign used in Australia showing 50 km/h (all speed limit signs are rectangular)File:Sweden road sign C31-5.svg|Alternative Vienna Convention sign with an amber background used in few countries, such as Sweden, Finland and IcelandFile:IE road sign RUS-043.svg|Ireland includes the text "km/h" since going metric in 2005File:Indonesia New Road Sign Pro 4h.png|Indonesia (in km/h) includes the text "km" on the top right corner; this model was also used by a number of European countries such as Germany, Italy and Switzerland until the 1960s.File:Japan road sign 323 (50).svg|Japan uses blue numerals; km/hFile:China road sign 禁 38 (40).svg|China (Mainland); km/hFile:Samoa - Speed Limit.svg|Samoa uses both miles per hour and kilometres per hourFile:UAE Speed Limit - 60 kmh.svg|The United Arab Emirates and Saudi Arabia (km/h) use both Western Arabic and Eastern Arabic numeralsFile:CA-ON road sign Rb-001-060.svg|Canada (displayed in km/h; All speed limit signs are MUTCD style)File:Ontario Rb-1A.svg|Canada (Ontario)File:British Columbia R-004-50.svg|Canada (Yukon and British Columbia)File:MUTCD R2-1.svg|United States (in mph)File:Oregon-speed.svg|United States (Oregon variant)File:NYSDOT NYR2-2.svg|United States (New York variant; "CITY", "VILLAGE", "TOWN", or a variant of the word "AREA" can be used in place of "STATE")WEB, New York State Department of Transportation, New York State Supplement to the Manual on Uniform Traffic Control Devices for Streets and Highways,weblink 2011, Section 2B.13, The NYR2-4, NYR2-5, and NYR2-6 signs...shall be used for posting area speed limits which are essentially city-wide, village-wide, and town-wide, respectively.... The word 'AREA' in the NYR2-3 sign may be replaced by other generic legend (for example, 'CAMPUS', 'PLAZA', 'MALL', 'PARK', etc.) where it would more clearly and appropriately identify a physically defined area., File:MUTCD R2-1 METRIC.svg|United States (metric)File:Peru road sign R-30.svg|Peru (metric, all speed limit signs are rectangular, and the reversed MUTCD order is used there)Some speed limits are applicable to a zone.File:Zeichen 274.1 - Beginn einer Tempo 30-Zone, StVO 2013.svg|Zone 30 entry in Germany with 30 km/h speed limitFile:Zeichen 274.2 - Ende einer Tempo 30-Zone (einseitig), StVO 2013.svg|Zone 30 end in GermanyFile:Signal B30.svg|Zone 30 entry in France with 30 km/h speed limitFile:France road sign B51 (30).svg|Zone 30 end in France

Minimum speed limit

Minimum speed limits are often expressed with signs using blue circles, based on the obligatory sign specifications of the Vienna Convention on Road Signs and Signals. In the United States, minimum speed limit signs are identical to their respective maximum speed limit signs, with SPEED LIMIT replaced with MINIMUM SPEED.{{Citation needed|date=June 2019}} Some South American countries (e.g.: Argentina) use a red border.{{Citation needed|date=April 2022}} JapanWEB, 2018-02-13, Driving in Japan - essential info if you plan to drive in Japan (2018),weblink 2021-05-29, Kyushu Journeys, and South Korea{{Citation needed|date=May 2021}} use their normal speed limit sign, with a line below the limit. File:Zeichen 275 - Vorgeschriebene Mindestgeschwindigkeit, StVO 1992.svg|Common minimum speed limit signFile:UAE Minimum Speed Limit - 60 kmh.svg|The United Arab Emirates and Saudi Arabia (km/h) use both Western Arabic and Eastern Arabic numeralsFile:Argentina road sign R16.svg|Argentina, km/hFile:Québec P-070-1-60.svg|Canada, km/h (rare outside the province of Quebec)File:Chile road sign RR-2 (40).svg|Chile; km/hFile:China road sign 示 16(60).svg|China (Mainland); km/hFile:Colombia road sign SR-30A.svg|Colombia; km/hFile:Indonesia New Road Sign Mndtry 44.png|Indonesia (includes the text "km" on the top right corner); km/hFile:Japan road sign 324 (30).svg|Japan; km/hFile:Philippines road sign R4-3 (40).svg|Philippines; km/hFile:South Korea road sign 225.svg|South Korea (which looks similar to this sign from Japan except the numerals are black); km/hFile:UK traffic sign 672.svg|UK minimum speed limit sign, in mphFile:MUTCD R2-4.svg|United States; mphFile:MUTCD R2-4a.svg|United States (dual maximum and minimum speeds)File:MUTCD R2-4 METRIC.svg|United States (metric)File:MUTCD R2-4a METRIC.svg|United States (metric, dual maximum and minimum speeds)

Special speed limits

In some countries, speed limits may apply to certain classes of vehicles or special conditions such as night-time. Usually, these speed limits will be reduced from the normal limit for safety reasons. File:Au.speedlimit.40 at times.svg|Australia – Speed limit during certain timesFile:AU-QLD road sign R4-Q05.svg|Australia – Road Train speed limitFile:New Zealand RG-3.svg|New Zealand – Limited Speed Zone (Maximum speed limit is {{cvt|100|kph}}, reduces to {{cvt|50|kph}} if dangerous conditions exist such as bad weather)File:RO road sign C30d.svg|Romania – Car and truck speed limitFile:MUTCD Sign Assembly - R2-1 with G20-5aP.svg|United States – Roadworks zone speed limitFile:MUTCD R2-2.svg|United States – Trucks speed limitFile:Virginia R2-VP1.svg|United States – Towed vehicles speed limitFile:MUTCD R2-3.svg|United States – Night time speed limitFile:MUTCD EM2-3.svg|Unique speed limit sign in the United States on evacuation routes requiring drivers to maintain the maximum safe speedFile:Korea Traffic Safety Sign - Assistance - 409 Safety Speed.svg|Safe speed sign in South Korea

Speed limit derestriction

(File:D984 03 - Fin de limitation à 30 km par heure.jpg|thumb|End of 30 km/h speed limit; previous speed limit applies.)(File:UK national speed limit signs on a single-carriageway.jpg|thumb|The UK national speed limit of {{convert|60|mph}} for ordinary vehicles applies beyond this sign.)In some countries, derestriction signs are used to mark where a speed zone ends. The speed limit beyond the sign is the prevailing limit for the general area; for example, the sign might be used to show the end of an urban area. In the United Kingdom, the sign means that the national speed limit applies ({{cvt|60|mph}} on open roads and {{cvt|70|mph}} on dual carriageways and motorways). In New Zealand it means you are on an open road, but the maximum legal speed of {{cvt|100|kph}} still applies.WEB, About limits - Speed limits,weblink The official New Zealand Road Code, New Zealand Transport Agency, 2012-08-08, Open road speed limits - The signs below mean that the maximum speed that you can travel at is 100 km/h., On roads without general speed limits, such as the German Autobahn, a portion of the Stuart Highway, and rural areas on the Isle of Man, it means the end of all quantitative speed limits.{{Citation needed|date=June 2019}}File:Spain traffic signal r501.svg|Common maximum speed limit derestriction signFile:Italian traffic signs - fine limite minimo di velocità 30.svg|Common minimum speed limit derestriction signFile:Italian traffic signs - fine velocità consigliata 60.svg|Common advisory speed limit derestriction signFile:Australia road sign R4-2.svg|Australia,WEB, Rule 21, Australian Road Rules,weblink 2011-01-12, 2012-08-08, dead,weblink" title="web.archive.org/web/20120505041544weblink">weblink 2012-05-05, now relatively rareFile:Australia road signs R4-12 (60).svg|AustraliaFile:New Zealand road sign R1-3.svg|Belgium, United Kingdom, Ireland pre-2005, New Zealand, Singapore, Malaysia and SwitzerlandFile:China road sign 禁 39 (40).svg|China(Mainland)File:Zeichen 282 - Ende sämtlicher Streckenverbote, StVO 1970.svg|GermanyFile:Japan road sign 323 (40) and 507-C.svg|JapanFile:Japan road sign 323 (40) and 507-A.svg|Japan – Left arrow (Right arrow means "from here")File:Philippines road sign R4-2.svg|PhilippinesFile:Philippines road sign R4-2P (60).svg|PhilippinesFile:NYSDOT NYR2-11.svg|End speed limit 35 mph United StatesFile:Virginia R2-V2.svg|End speed limit (custom) United States (archaic)

Advisory speed limit

{{Further|Advisory speed limit}}(File:Geschwindigkeitssignal.jpg|thumb|upright=0.65|Traffic signals showing an advisory speed limit)Advisory speed limits may provide a safe suggested speed in an area, or warn of the maximum safe speed for dangerous curves.{{Citation needed|date=June 2019}}In Germany, an advisory speed limit may be combined with a traffic signal to recommend the speed at which drivers should drive to reach the next light at its green phase, thereby avoiding a stop.BOOK, ((Forschungsgesellschaft für Straßen- und Verkehrswesen)), Begriffsbestimmungen, Teil: Verkehrsplanung, Straßenentwurf und Straßenbetrieb, FGSV Verlag, 2000, 81, BOOK, Andreas Richter, Geschwindigkeitsvorgabe an Lichtsignalanlagen, DUV, 2005, 3-8244-0828-7, 33–34,

Technology

Some European cars include in-vehicle systems that support drivers’ compliance with the speed limit, known as intelligent speed adaptation (ISA). ISA supports drivers in complying with the speed limit in various parts of the network, while speed limiters for heavy goods vehicles and coaches only govern the maximum speed. These systems have positive effects on speed behaviour, and improve safety. A speed-limiting device, such as ISA are considered useful by 25% of European car drivers.WEB,weblink Speed and speed management, 2015, ec.europa.eu, 2020-12-29, In 2019, Google Maps integrated alerts for speed traps within its application, along with audible alerts for nearby speed cameras.WEB,weblink Google Maps appears to be testing speed trap icons w/ audible alerts, rolling out for some users, Schoon, Ben, 2019-01-16, 9to5Google, 2019-01-16, The technology was first developed by Waze, with requests for it to be removed from the application by police officers.WEB,weblink Police Ask Waze To Remove Speed Trap Alerts To Protect Cops, 2015-01-26, Consumerist, 2019-01-16,

See also

{{div col|colwidth=18em}}

• Advisory speed limit
• Assured clear distance ahead (ACDA)
• Design speed
• Functional classification
• Negligence per se
• Operating speed
• Radar speed sign
• Solomon curve
• Speed limits by country
• Stopping sight distance
• Traffic violations reciprocity
• Traffic psychology

{{Div col end}}

Notes

{{Reflist|40em|group="n"}}

Documents referenced from 'Notes' section

• WEB,weblink Synthesis of Safety Research Related to Speed and Speed Limits, Federal Highway Administration, 2013-09-23, 1998,
• WEB, Review and Analysis of Posted Speed Limits and Speed Limit Setting Practices in British Columbia, Spring 2003, British Columbia Ministry of Transportation,weblink 2019-05-16,
• BOOK, World Health Organization, 2004,weblink World report on road traffic injury prevention, World Health Organization, 92-4-156260-9, 2010-04-13,
• {{anchor|Dft2008a}} WEB, Reported Road Casualties Great Britain: 2008 Annual Report, Department for Transport, 2008,weblink 2010-01-09,

References

{{Reflist}}

Further reading

• Actual Speeds on the Roads Compared to the Posted Limits, Final Report 551, Arizona Dept of Transportation, October 2004.
• Effects of Raising and Lowering Speed Limits on Selected Roadway Sections {{Webarchive|url=https://web.archive.org/web/20080625230932weblink |date=2008-06-25 }}, United States Publication No. FHWA-RD-97-084, January 1997.
• Effect of 20 mph traffic speed zones on road injuries in London, 1986–2006: controlled interrupted time series analysis British Medical Journal 2009.
• Engineering Speed Limits – FHWA Safety Program United States Department of Transportation – Federal Highway Administration, Office of Safety, 1200 New Jersey Avenue, SE, Washington DC 20590.
• "Reducing Speeding-Related Crashes Involving Passenger Vehicles". National Transportation Safety Board, 490 L'Enfant Plaza, SW, Washington, D.C. 20594, July 2017.
• Special Report 254: Managing Speed, Transportation Research Board, 1998.
• The Speeding Driver: Who, How and Why? A research report by the Scottish government into the psychology of the speeding driver.
• weblink" title="web.archive.org/web/20060207044214weblink">Transport, Local Government and the Regions – Ninth Report The comprehensive UK report into the effects of speeding.
• JOURNAL, Elvik, R., 10.1146/annurev-publhealth-031811-124634, Speed Limits, Enforcement, and Health Consequences, Annual Review of Public Health, 33, 225–238, 2012, 22224882, free,
• BOOK, TrafikksikkerhetshÃ¥ndboken, 2000, Transportøkonomisk Institutt, Oslo, Norway,weblink 8 August 2012, no, 3.11 Fartsgrenser,
• JOURNAL, Khondaker, Bidoura, Kattan, Lina, Variable speed limit: A microscopic analysis in a connected vehicle environment, Transportation Research Part C: Emerging Technologies, September 2015, 58, 146–159, 10.1016/j.trc.2015.07.014, free,

Law Review

• {{anchor|6_ALR3d_1326}}BOOK, American Law Reports--Annotated, 3rd Series, Indefiniteness of automobile speed regulations as affecting validity, R. A. Vinluan, The Lawyers Co-operative Publishing Company; Bancroft-Whitney; West Group Annotation Company, 6, 1326, 2008,
• {{anchor|50_ALR2d_343}}BOOK, American Law Reports--Annotated, 2nd Series, Meaning of "residence district," "business district," "school area," and the like, in statutes and ordinances regulating speed of motor vehicles, C. C. Marvel, The Lawyers Co-operative Publishing Company; Bancroft-Whitney; West Group Annotation Company, 50, 343, 2010,

External links

{{Commons category multi|Speed limit signs|Driver speed and relative risk of an accident}}

• A Walk Through The History of Speed Limit Signs in The US
• John F. Carr's State Traffic and Speed Laws
• Global map of speed limits from OpenStreetMap {{Webarchive|url=https://web.archive.org/web/20151113032908weblink |date=2015-11-13 }}

{{Traffic signs}}{{Traffic law}}{{Authority control}}