Because they're BUS lanes, not BUS/CYCLE lanes.
There's no specific signage, but local regulations specify that you can't. I took the bother to check. Last time I was in Madrid I noticed mopeds are now allowed into bus lanes, but bicycles are still excluded.
@sindandune started
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There's no specific signage, but local regulations specify that you can't. I took the bother to check. Last time I was in Madrid I noticed mopeds are now allowed into bus lanes, but bicycles are still excluded.