There is like one state that does not allow a blinkie (do not remember which). But who cares, when you are talking about your safety.

A solid light does make it easier for motorist to judge their distance to you. And the blinkie is more distinctive of a cyclist ahead.

With that knowledge, at night I run a solid red light on the seatpost, a blinking red light on my left ankle and a flashing blue light on my left wrist.

Yes, I know many states outlaw blue lights for other than police, BUT a federal court found that a blue light was OK for use as a safety measure and as long as you do not use it for pulling people over, then it is legal regardless of state laws.