Most states have a law that says it is illegal to open you car door into oncoming traffic,meaning,if you go to the store and park on the street,getting out on the driver side you are breaking the law.New Mexico was a nightmare as far as police were concerned.Visited family there twice.Vowed never to go back.Police checkpoints everywhere.We were stopped 3 times just going to the store.A 3 mile trip!
I lived in Colorado some years ago, and got a ticket for driving in the wrong (passing) lane when I wasn't passing. My car had out-of-state plates at the time, since I'd only moved there a few weeks before.
In downtown Fort Atkinson, WI there are explicit signs warning "Unlawful to open door into traffic", but that doesn't mean that it's unlawful to disembark via the driver's side door; it means that one must wait until there are no moving vehicles in the rightmost traffic lane before doing so (either because there are no vehicles at all there, or because they have stopped at a traffic signal).