When driving, I'm not bothered by the flashing light of other bikers during the day. In darkness, it's a little annoying but tolerable.

I use the bright flashing light both front and back for most rides I do which are in the daytime. The low flashing light for long rides where battery life is an issue. It also is the recommended setting by most of the various agencies and law enforcement around here. No specific laws, though many think it law.

I do know the the brighter than heck strobes they are putting on law enforcement and emergency vehicles lately make if very unsafe at twilight and night time while it is raining. At least to me it does.