My state has unambiguously defined bicycles as vehicles, perhaps to avoid exactly this question. It also avoids the need to rewrite the vehicle code to specifically include bicycles. There have been exceptions added to the vehicle code to allow bikes to do things or go places where other vehicles are forbidden but there was no need to rewrite the vehicle code to specifically require them to stop at red lights. They are vehicles, so must stop.

In this game, in my state, bicycles would not be allowed unless the sign mentioned the law that allows them.