Editing Speed limit (section)

=== 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),<ref>{{cite report|url=http://www.ite.org/standards/speed_zoning.pdf|title=Speed Zoning Information|publisher=[[Institute of Transportation Engineers]]|access-date=2009-09-17|date=2004-03-22|archive-date=2010-07-05|archive-url=https://web.archive.org/web/20100705040529/http://www.ite.org/standards/speed_zoning.pdf|url-status=dead}}</ref><ref>[https://mutcd.fhwa.dot.gov/htm/2009r1r2/part2/part2b.htm#section2B13 MUTCD Sections 2B.13-16] #12</ref><ref>{{cite web|url=https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=VEH&sectionNum=21400|title=California Vehicle Code § 21400(b)|publisher=The State of California|access-date=2020-04-07|date=2012-01-01}}</ref> and in the US is frequently set {{cvt|4|to|8|mph|0}} below that speed.<ref>{{cite book|url=http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_504.pdf|title=NCHRP Report 504 – Design Speed, Operating Speed, and Posted Speed Practices|publisher=[[National Academies Press]]|location=[[Washington, D.C.]]|work=onlinepubs.trb.org|date=2003-10-06|author=Transportation Research Board of the National Academies|author2=Kay Fitzpatrick|author3=Paul Carlson|author4=Marcus A. Brewer|author5=Mark D. Wooldridge|author6=Shaw-Pin Miaou|author7=Texas Transportation Institute|isbn=0-309-08767-8|issn=0077-5614|archive-url=https://web.archive.org/web/20141021111234/http://onlinepubs.trb.org/onlinepubs/nchrp/nchrp_rpt_504.pdf|archive-date=2014-10-21|url-status=live|page=88|access-date=2009-09-16}}</ref> 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").<ref name="tti.tamu.edu">{{cite report|title=Speed: Understanding Design, Operating, and Posted Speed|first1=R.A.|last1=Krammes|first2=K.|last2=Fitzpatrick|first3=J.D.|last3=Blaschke|first4=D.B.|last4=Fambro|url=http://tti.tamu.edu/documents/1465-1.pdf|date=March 1996|publisher=Texas Transportation Institute|location=College Station, TX|id=Research Report 1465-1}}</ref> 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.<ref>{{cite web|url=https://azdot.gov/business/engineering-and-construction/traffic/faq/establishing-speed-limits|title=Establishing Speed Limits|website=azdot.gov}}</ref><ref>{{cite web|title=ESTABLISHING SPEED LIMITS: a case of "MAJORITY RULE"|url=https://www.ksdot.org/Assets/wwwksdotorg/bureaus/burTrafficSaf/brochures/pdf/speedlimitspb.pdf|publisher=Kansas Department of Transportation}}</ref> 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.<ref>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,'' [[American Association of State Highway and Transportation Officials|AASHTO]], 4th Ed., 2001; {{ISBN|1-56051-156-7}}</ref><ref>{{cite web|url=https://safety.fhwa.dot.gov/uslimits/|title=USLIMITS2 - Safety - Federal Highway Administration|website=[[Federal Highway Administration|Federal Highway Administration (FHWA)]]}}</ref>

The maximum speed permitted by statute, as posted, is normally based on ideal driving conditions and the basic speed rule always applies.<ref>{{cite web|url=http://law.justia.com/cases/california/calapp2d/22/636.html|title=Riggs v. Gasser Motors, 22 Cal. App. 2d 636|publisher=Official California Appellate Reports (2nd Series, Vol. 22, p. 22)|date=1937-09-25}}</ref> Violation of the statute generally raises a [[rebuttable presumption]] [[negligence per se|of negligence]].<ref>{{cite web|date=1958-07-17|title=''Alarid v. Vanier,'' 50 Cal.2d 617|url=http://scocal.stanford.edu/opinion/alarid-v-vanier-26881|publisher=Official California Reports, 2nd Series Vol. 50, p. 617 (California Supreme Court reporter)}} See [http://www.lexisnexis.com/clients/CACourts/ Official California Reports online]</ref>

On 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&nbsp;km/h
!80&nbsp;km/h (50&nbsp;mph)
!100&nbsp;km/h (60&nbsp;mph)
!120&nbsp;km/h (75&nbsp;mph)
!140&nbsp;km/h (85&nbsp;mph)
|-
|Motorway || x || 80 || 100 || 120 || 140
|-
|Express road || 60 || 80 || 100 || 120 || x
|-
|Road || 60 || 80 || 100 || x || x
|}