Motorcycles aren’t the only engine-powered two-wheelers on the road. Scooters and mopeds have been around for years, and innovative motorbikes are becoming popular in many cities across the U.S. The variety of vehicles available today leaves many motorists wondering where they stand legally.

Do you need a motorcycle license for a scooter, moped or motorbike? Do you need insurance, registration and license plates? What about a helmet? The short answer is: it all depends on where you live.

Each state has its own laws regarding scooters, mopeds and motorbikes. Even the definitions vary widely, with some states lumping scooters and mopeds together, while others consider scooters and motorcycles to be in the same category. Then there’s electric and gas-powered motorized bicycles, which many states are still figuring out how to regulate.

There are a few websites out there to help motorists wade through this two-wheeled gray area. Moped2.org and mopedarmy.com have some helpful information for a quick reference. However, to know what the law is in your specific state it’s best to consult DMV.org.