Mandatory sign

[1] 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).

Canada has developed its own style using a green circle, which is not used in any other country.

right only only only only 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 snowmobile tracks can also be designated with mandatory signs.

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.