Editing Stop sign (section)

==Design and configuration==
The 1968 [[Vienna Convention on Road Signs and Signals]] allows for two types of stop signs as well as several acceptable variants. Sign B2a is a red octagon with a white '''{{smallcaps|stop}}''' legend. The European Annex to the convention also allows the background to be "light yellow". Sign B2b is a red circle with a red inverted triangle with either a white or yellow background, and a black or dark blue '''{{smallcaps|stop}}''' legend. The Convention allows for the word "STOP" to be in either English or the national language of the particular country. The finalized version by the [[United Nations Economic and Social Council]]'s Conference on Road Traffic in 1968 (and [[coming into force|in force in 1978]]) proposed standard stop sign diameters of 600, 900 or 1200&nbsp;mm (24, 36 or 48 inches).

The United Kingdom and New Zealand stop signs are 750, 900 or 1200&nbsp;mm (about 30, 36 or 48 inches), according to sign location and traffic speeds.<ref>{{cite web |url=http://www.dft.gov.uk/pgr/roads/tss/tsmanual/tsmchapter3.pdf |title=UK Department of Transport. Traffic Signs Manual, Chapter 3: Regulatory Signs |date=9 September 2008 |url-status=dead |archive-url=https://web.archive.org/web/20100601101058/http://www.dft.gov.uk/pgr/roads/tss/tsmanual/tsmchapter3.pdf |archive-date=1 June 2010  }}&nbsp;{{small|(2.0&nbsp;MB)}}</ref><ref>[http://www.nzta.govt.nz/consultation/tcd-traffic-signs/index.html New Zealand Transport Agency. Traffic Control Devices Manual: General requirements for traffic signs] {{Webarchive|url=https://web.archive.org/web/20150117052207/http://nzta.govt.nz/consultation/tcd-traffic-signs/index.html |date=17 January 2015 }}, {{small|(963&nbsp;KB)}}</ref>

In the United States, stop signs are {{convert|30|in|cm}} across opposite flats of the red [[octagon]], with a {{sfrac|3|4}}-inch (2&nbsp;cm) white border. The white uppercase '''{{smallcaps|stop}}''' legend is {{convert|10|in|cm}} tall.<ref>{{Cite web|url=https://mutcd.fhwa.dot.gov/SHSm/regulatory.pdf|title=Standard Highway Signs manual, 2004 Metric edition}}</ref><ref name="SHS_English">{{cite web|url= https://mutcd.fhwa.dot.gov/SHSe/Regulatory.pdf |title=Standard Highway Signs manual, 2004 English edition }}&nbsp;{{small|(8.49&nbsp;MB)}}</ref> Larger signs of {{convert|35|in|cm}} with {{convert|12|in|cm|adj=on}} legend and {{convert|1|in|cm|adj=on}} border are used on multi-lane expressways. Regulatory provisions exist for extra-large {{convert|45|in|cm|adj=on}} signs with {{convert|16|in|cm|adj=on}} legend and {{sfrac|1|3|4}}-inch border for use where sign visibility or reaction distance are limited, and the smallest permissible stop sign size for general usage is {{convert|24|in|cm}} with an {{convert|8|in|cm|adj=on}} legend and {{sfrac|5|8}}-inch (1.5&nbsp;cm) border.<ref name="MUTCD03_2B">{{cite web|url=https://mutcd.fhwa.dot.gov/HTM/2003r1/part2/part2b1.htm#section2B04|title=Manual on Uniform Traffic Control Devices 2003, Section 2B |publisher=[[Federal Highway Administration|Federal Highway Administration (FHWA)]] |access-date=11 March 2012}}</ref> The [[SI|metric]] units specified in the US regulatory manuals are [[Rounding|rounded approximations]] of [[United States customary units|US customary units]], not exact conversions.<ref name="SHS_English"/><ref name="SHS_Metric">{{cite web|url= https://mutcd.fhwa.dot.gov/SHSm/regulatory.pdf |title=Standard Highway Signs manual, 2004 Metric edition }}&nbsp;{{small|(8.36&nbsp;MB)}}</ref> The field, legend, and border are all [[Retroreflector|retroreflective]].

Some modern stop signs have flashing LEDs around the perimeter, which has been shown to substantially reduce crashes.<ref>[https://ctre.iastate.edu/research-synthesis/intersections/stop-signs/leds/ Increase Visibility of Stop Signs:&nbsp;LEDs Around Stop Sign Face]</ref>

<gallery class="center">
File:Vienna_Convention_road_sign_B2a.svg|B2a
File:Vienna Convention road sign B2a-EA.svg|Acceptable variant of B2a in the European Annex
File:Vienna Convention road sign B2b-V1.svg|B2b
File:Vienna Convention road sign B2b-V2.svg|Acceptable variant of B2b
File:Vienna Convention road sign B2b-V3.svg|Acceptable variant of B2b
File:Vienna Convention road sign B2b-V4.svg|Acceptable variant of B2b
</gallery>