Editing Speed limit (section)

{{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}}
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{{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 hour]].]]
'''Speed 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.<ref>[https://autorevue.at/ratgeber/mindestgeschwindigkeit-autobahn-oesterreich MINIMUM SPEED: REGULATION AND PENALTIES IN AUSTRIA], 23.02.2016, Autorevue Austria.</ref> 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 [[Autobahn]]en in [[Germany]].<ref>{{Cite web|url=https://www.german-way.com/travel-and-tourism/driving-in-europe/driving/autobahn/driving-on-the-autobahn/|title= Driving on the Autobahn|website= www.german-way.com|access-date=2019-04-14}}</ref>

The first numeric speed limit for mechanically propelled road vehicles was the {{cvt|10|mph|0}} limit introduced in the [[United Kingdom]] in 1861.<ref>{{Cite book|url= https://books.google.com/books?id=Rj2sDAAAQBAJ&q=The+first+maximum+speed+limit+for+automobiles+was+the+10+mph+(16+km/h)+limit+introduced+in+the+United+Kingdom+in+1861&pg=PA19|title= Traffic Networks as Information Systems: A Viability Approach|last1= Aubin |first1= Jean-Pierre|last2= Désilles|first2= Anya|date= 2016-07-13|publisher=Springer|isbn=9783642547713}}</ref>

{{As of | 2018}} the highest posted speed limit in the world is {{cvt|160|km/h|0}}, applied on two [[motorway]]s in the [[United Arab Emirates|UAE]].<ref>{{Cite news|url= https://www.arnnewscentre.ae/new-speed-limit-for-abu-dhabis-mafraq-ghweifat-highway|title=New speed limit for Abu Dhabi's Mafraq-Ghweifat highway - ARN News Centre|date=2018-01-30|work=ARN News Centre|access-date=2018-01-31|archive-url= https://web.archive.org/web/20180131205406/https://www.arnnewscentre.ae/new-speed-limit-for-abu-dhabis-mafraq-ghweifat-highway|archive-date=2018-01-31|url-status=dead}}</ref> 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]].<ref>{{Cite web | url=https://www.diplomatie.gouv.fr/fr/conseils-aux-voyageurs/conseils-par-pays-destination/emirats-arabes-unis/ |title = Emirats arabes unis- Dernière minute| date=22 April 2024 }}</ref> Additionally, "drivers often drive at high speeds [and] unsafe driving practices are common, especially on inter-city highways. On highways, unmarked [[speed bump]]s and drifting sand create additional hazards", according to a travel advisory issued by the [[U.S. State Department]].<ref>{{Cite web | url=https://travel.state.gov/content/travel/en/international-travel/International-Travel-Country-Information-Pages/UnitedArabEmirates.html |title = United Arab Emirates International Travel Information}}</ref>

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 [[Epidemiology of motor vehicle collisions|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.<ref group="n">{{harvtxt|World Health Organization |2004}}</ref> As of 2021, the WHO estimates that approximately 1.3 million people die of road traffic crashes each year.<ref>{{Cite web|last=Pietrasik|first=T|date=21 June 2021|title=Road traffic injuries |url=https://www.who.int/news-room/fact-sheets/detail/road-traffic-injuries|access-date=2021-12-25 |website=www.who.int}}</ref>

Authorities may also set speed limits to reduce the [[environmental impacts of roads|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&nbsp;km/h (81&nbsp;mph) speed limit across the Autobahnen to curb fuel consumption and carbon emissions.<ref>{{Cite news|url= https://www.thelocal.de/20190121/german-weighing-speed-limit-on-autobahn|title=Germany considers Autobahn speed limit to fight climate change|date= 2019-01-21|newspaper= The Local Germany|language= en-GB |access-date=2019-04-14}}</ref> Some cities have reduced limits to as little as {{convert|30|km/h|abbr= on}} for both safety and efficiency reasons.<ref>{{Cite web|url= http://www.monash.edu.au/miri/research/reports/muarc276.pdf|title=The impact of lowered speed limits in urban and metropolitan areas}}</ref> However, some research indicates that changes in the speed limit may not always alter average vehicle speed.<ref>
{{cite book|last1= Parker|first1= M. R. Jr.|title=Effects of Raising and Lowering Speed Limits on Selected Roadway Sections, FHWA-RD-9 7-084|date=1997|publisher=Federal Highway Commission|location= Washington DC|pages=85–87|url= https://www.fhwa.dot.gov/publications/research/safety/97084/97084.pdf|access-date= 5 February 2017 | quote = There is statistically sufficient evidence [...] to reject the hypothesis that driver speeds do not change when posted speed limits are either raised or lowered.}}
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Lower speed limits could reduce the use of over-engineered vehicles.<ref>
{{cite book
 |author1                = Great Britain: Parliament: House of Commons: Transport Committee
 |author-link1         = House of Commons of the United Kingdom
 |orig-date            = November 2004
 |chapter              = Memorandum by Greenspeed (RP22)
 |title                = Road Pricing: The Next Steps; Seventh Report of Session 2004-05, Volume 2
 |url                  = https://books.google.com/books?id=Lx7-pq8NEBAC
 |series               = Volume 218 of Paper (Great Britain. Parliament. (Session 2004-05). House of Commons))
 |date = 2 August 2005
 |location             = London
 |publisher            = The Stationery Office
 |publication-date     = 2005
 |page                 = 171
 |isbn                 = 9780215025661
 |access-date          = 9 December 2021
 |quote                = The introduction of lower speed limits could be extremely cheap and need not be delayed. [...] Just as modern cars have top speeds suitable for German Autobahns, if the {{cvt|70|mph|km/h}} limit is maintained car design will not make the changes necessary to an integrated and sustainable transport system.
}} 
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