Originally Posted by
KraneXL
There's no exception, but it might be ignored. Its pretty generally understood that cyclist have the same rights and must follow the same laws as do motorist when on the roadway. I would think that would be particularity important when consider head/tail lights.
A white headlight is legal and required although I wouldn't think the light you describe (Is it a laser aimed at the ground?) would get you onto trouble unless it was visible/distracting to motorist. Too bad you didn't upload a photo with your question. Blue -- and red other than in designated locations -- are reserved for police/emergency vehicles.
The only prohibition of a colored light for bicycles in California that I can find is given in CVC 21201.3:
" No person shall display a steady or flashing blue warning light on a bicycle or motorized bicycle except as authorized under subdivision (a)." [which allows blue on police bikes]
There are additional rules prohibiting certain types and colors of lights on 'vehicles' but these don't apply to bicycles in California since the CVC definition of vehicle specifically excludes bicycles.