In some places in Rio the rightmost lane is bus-only (and I believe taxis can drive there too). It's clearly marked with ÔNIBUS written all over and blue line between it and other lanes.
I was cycling on the next rightmost lane, and I was constantly being honked at by drivers. Then I moved to that bue lane and taxis passing there were honking at me. There was no bike-only lane (maybe they were doing that just to signal that they're about to pass me though).
Can I be be using that lane then? I didn't find any clear info on the internet.