[davedx]

It goes beyond that in the Netherlands. A lot of bus lanes have their own traffic light system -- they have very small lights to show when they can go or stop. :)

[telegato]

This also exists in Germany

https://de.wikipedia.org/wiki/%C3%96PNV-Bevorrechtigung

(Sorry, no english version available)

[Symbiote]

These exist in Britain, but are only used for trams.

http://www.ukmotorists.com/tram_signs.asp

For buses, there would be a normal traffic light controlling only a bus lane, usually labelled with the blue buses only sign. It's not very common, but I know a couple of cases in London.