Whether or not it's a motorcycle in the US will depend on the state. Most states count 3-wheelers as motorcycles, which is how the Polaris Slingshot, which weig

Whether or not it's a motorcycle in the US will depend on the state. Most states count 3-wheelers as motorcycles, which is how the Polaris Slingshot, which weighs more and does not meet auto crash standards, is sold in the US. The US federal definition of a motorcycle is basically anything you can drive that has less than four wheels.