Mandatory sign - wikipedia Mandatory sign Uses Uses Uses Uses a combination of both Type A and Type B Uses ( historically used ) Does not use the mandatory sign group Mandatory signs are road signs which are used to set the obligations of all traffic which use a specific area of road. Unlike prohibitory signs, mandatory signs tell traffic what it must do, rather than must not do. Most mandatory road signs are circular, may use white symbols on a blue background with white border or black symbols on a white background with a red border, although the latter is also associated with prohibitory signs. Contents 1 Design 2 Uses 2.1 Segregation of roads 2.2 Instruction 3 References Design A `` pass on the left '' sign embedded into an illuminated plastic bollard in the United Kingdom. Mandatory signs are a subset of the regulatory sign group as defined by the United Nations Economic and Social Council in the Vienna Convention on Road Signs and Signals of 1968, and are often seen not just on their own, but used in conjunction with other signs, traffic lights and bollards as a form of visual shorthand within these objects. In Vienna Convention signatories, the mandatory sign is either a light blue circle with a white border ( Type A ) or a white circle with a red border ( Type B). The sign must be at least 60 cm ( 1.96 ft ) across on rural roads, or 40 cm ( 1.31 ft ) in built - up areas, although mandatory signs incorporated in traffic lights, bollards or larger road signs can be as little as 30 cm ( 0.98 ft ) in diameter. The mandatory sign group is not used in Australia, Ecuador, or the United States, none of which are signatories to the Vienna Convention. Canada has developed its own style using a green circle, which is not used in any other country. The U.S. instead uses black arrows and border on taller - than - wide rectangular white signs, often with the word ONLY below the arrow. Below is a chart comparing some of the most common mandatory signs. Proceed straight Turn right Permitted directions Buses only Bicycle path Segregated pathway Seatbelts required Snow chains required Type A Type B Canada N / A N / A ^ Jump up to : Canada uses a type of sign other than mandatory for this purpose. Uses Segregation of roads Mandatory road signs can be used to allocate certain areas to specific vehicles - the Vienna Convention explicitly mentions footpaths, cyclepaths and bridleways, but tramways, bus lanes, taxi lanes, HOV lanes and snow mobile tracks can also be designated with mandatory signs. When a specific area of roadway is designated with a mandatory sign specifying a vehicle type, all traffic of this type must use this area if possible. These signs can be combined by putting one pictogram above the other. If the pictograms are side - by - side however, with the sign divided by a white vertical line, each type of vehicle must stay within the lane indicated by the sign. A red line through a mandatory sign indicates not that a vehicle of a specific type is prohibited from entering the designated area, but that the area is now deregulated and any vehicle may use it. Instruction Mandatory signs can also be used to issue instructions to all vehicles - common examples include `` pass on this side '' signs seen at roadworks, and `` compulsory roundabout '' signs seen at mini-roundabouts. Other signs of the type include `` attach snow chains '' and `` remove snow chains '' seen at the entry and exit points of mountainous areas, and `` compulsory direction for vehicles carrying dangerous loads '', used to divert vehicles carrying explosives or poisonous chemicals away from areas with open flames such as oil refineries. Minimum speed limits can also be defined using mandatory road signs, although such signs are rare in most countries ; the U.S., which does not use mandatory signs, instead places minimum speed limits on the same type of panel as maximum speed limits. References ^ Jump up to : Vienna Convention on Road Signs and Signals ( PDF ). United Nations Economic and Social Council. 6 June 1978. pp. 44 -- 46. Retrieved 2007 - 09 - 14. ^ Jump up to : `` Regulatory Signs ''. Manual on Uniform Traffic Control Devices. Federal Highway Administration. Retrieved 2007 - 09 - 14. Traffic signs Signs Warning sign Regulatory sign Prohibitory traffic sign Mandatory sign Special regulation sign Stop sign Yield sign Crossbuck Dead End sign One - way traffic Speed limit ( by country ) Advisory speed limit Information sign Direction, position, or indication sign Variable - message sign Bilingual sign Driver location signs Logo sign Priority to the right By comparison Comparison of European road signs Comparison of MUTCD - influenced traffic signs Comparison of traffic signs in English - speaking countries By country Africa Botswana Mauritius South Africa Zimbabwe Asia Azerbaijan Bangladesh Brunei Cambodia China Hong Kong India Indonesia Iran Israel Japan Laos Malaysia Nepal Pakistan Singapore South Korea Sri Lanka Thailand Turkey United Arab Emirates Vietnam Europe Austria Bosnia and Herzegovina Czech Republic Denmark Estonia Finland France Germany Greece Iceland Ireland Italy Liechtenstein Netherlands Norway Poland Sweden Switzerland Ukraine United Kingdom Scotland Wales North America Canada Mexico United States Oceania Australia New Zealand South America Argentina Brazil Chile Colombia Lights Traffic light Traffic - light signalling and operation Traffic light control and coordination Typefaces Alfabeto Normale ( IT ) Austria ( AT ) Caractères ( FR ) Clarendon ( US ) Clearview ( US / CA / ID / PH / LK ) DIN 1451 ( DE / SADC ) Drogowskaz ( PL ) Enigmatic ( JP / KR ) Highway Gothic ( Global ) Bitstream Vera Sans ( TW ) Frutiger ( Europe ) GOST 10807 - 78 ( USSR ) GOST R 52290 - 2004 ( RU ) Hangil ( KR ) LLM Lettering ( MY ) Motorway ( Europe ) NPS Rawlinson Roadway ( US ) Panno ( KR ) SNV ( CH ) Tern ( Europe ) Trafikkalfabetet ( NO ) Transport ( UK ) Tratex ( SE ) Vialog ( JP ) Conventions Geneva Convention on Road Traffic Vienna Convention on Road Traffic Vienna Convention on Road Signs and Signals Manual on Uniform Traffic Control Devices ( US ) SADC Road Traffic Signs Manual ( SADC ) Traffic Signs Regulations and General Directions ( UK ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Mandatory_sign&oldid=813119687 '' Categories : Traffic signs Talk Contents About Wikipedia Башҡортса Français Қазақша Polski Русский Svenska తెలుగు Edit links This page was last edited on 1 December 2017, at 22 : 08. 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Question: what is the shape of mandatory traffic signs
Answer: circular