These exist in Britain, but are only used for trams.<p><a href="http:&#x2F;&#x2F;www.ukmotorists.com&#x2F;tram_signs.asp" rel="nofollow">http:&#x2F;&#x2F;www.ukmotorists.com&#x2F;tram_signs.asp</a><p>For buses, there would be a normal traffic light controlling only a bus lane, usually labelled with the blue buses only sign. It&#x27;s not very common, but I know a couple of cases in London.