Just check the laws in your state as it pertains to flashing headlights most are illegal.....
Summary: you're technically correct, but flash and modulate are two very different things, according to federal law. Federal law wins: states can't override federal law, and modulators
are legal in all states!
Now, the long version...
You're right - flashing lights are illegal in most states. But what does the term "flashing" mean?
Federal regulations defines "Flash"
as "a cycle of activation and deactivation of a lamp by automatic means continuing until stopped either automatically or manually."
But modulators don't flash! They... well, modulate! And the term "modulate" is defined, in absolutely no uncertain terms, by federal regulation Title 49 CFR, Part 571.108, section 7.9.4
States and political subdivisions cannot
make modulators illegal, according to Chapter 301, Section 30103, under Preemption
In response to a question concerning the rights of a state to make modulators illegal, the NHTSA Acting Chief Counsel, John Womack, told Signal Dynamics that states cannot
make them illegal. Period.
When states or political subdivisions have a law saying modulators are illegal (or the officer issues a ticket for "flashing lights"), as long as you have a modulator that meets federal specifications, a little thing called the United States Constitution says they lose. It's commonly called the Supremacy Clause
allowed to adopt their own law, as long as it is identical
to the federal law. Check the American Motorcyclists Association list of state laws to see if modulators are specifically mentioned
for your state.
I know the state of Washington has a specific law
, but it differs from federal law. So if you got a ticket in Washington for having your modulator hooked-up to your low beams, federal law preempts, you win (if you have a good lawyer). Washington law says modulators are legal at night - federal law says no, they are not legal at night
I've seen many posts saying that in the state of New York they are illegal. Odd, the NY DMV says they ARE legal
I live in Ohio, and the AMA sites says Ohio has a law allowing modulators. I searched, I couldn't find the exact Ohio law, so I contacted the AMA legal-eagle types, and they gave me the number of the law. I looked it up, Ohio "references" FMVSS 571.108, thereby "adopting" it into Ohio law
Hope this helps.
Live to ride. Blink to live! Enjoy the ride.