'B' is for Bicycle? Yeah, nah
A white 'B' symbol, as a traffic light, normally relates to buses. If you're cycling in a bus lane that allows bikes, it means you can proceed. If you're NOT in that lane it doesn't apply to you.
So 'B' careful - if you see a white 'B', and you're not in the bus lane, or there's a red traffic light applying to your lane, or a red 'bike' symbol, think twice before proceeding!
Worth being clear on this, since Councils often plan for buses and bikes to be in close proximity, and the signals are often posted close together.
(CAN's not a legal or traffic-light expert! - this is our interpretation of info from those in the know so don't take our word for it, make sure you know the rules of the road!)
http://www.nzta.govt.nz/assets/resources/roadcode/gfx/special-traffic-si...