Originally Posted by kk610lt
Hi Raffy. I've had that same thought for a while. Seems to me that as long as it just modulates, I would think that it would be ok. I have also thought of a Moto Light side to side modulation would be work as well. Like a freight train.
We did some business at CCR in Osage Beach. I hope you are doing well.
Federal statutes control most vehicle lighting, and States cannot override those specific items. States can have additional regulations, as long as none of them conflict with or override the federal ones.
Headlight modulation is pretty strictly regulated, such as modulation rate, and modulation levels. The lights cannot be "flashed" on and off, but must modulate between a specific low level and full bright, and as Raffy pointed out, between morning and evening, not legal to modulate at night. Commercially available modulators have a sensor to prevent them operating below a set light level.
Side to side modulation is strictly forbidden. Two headlights can be modulated on a Car, but must modulate together.
Modulation of auxiliary lights would be questionable at best. May get away with it if the headlight is not modulated too, but I would not want to test law enforcement's outlook on it.
I had downloaded the federal regulations years ago, and just looked around on my system and found them. Attached. There is more about US federal vehicle lighting there than you could possibly want to know. Section on Motorcycle headlight modulation is section S7.9.4
Note, these are a few years old, so before depending on anything in them, get the latest version.