Depending on the design of the vehicle, a motorized trike may be categorized as a motorcycle, motor scooter, or simply the three-wheeled counterpart to a motorized or electric bicycle. The main difference between a motorcycle trike and a scooter trike is that motorcycles are sat on in a "saddle"-style seating (as with a horse), with the legs apart, and motorcycles have manual transmissions. Scooters have a "step-through" seating style, in which the driver sits on a more chair-like seat, with the legs together; as well, scooters have automatic transmissions. Laypersons often associate the engine size as a dividing line between motorcycles and scooters, since a typical scooter has a small 50 cc engine, but scooter engines can also be as large as 650cc as used in the Suzuki Burgman.
Motorcycles with sidecars are not usually considered tricycles. It can be harder to categorize three-wheeled automobiles. While some early prototype automobiles were steam tricycles, three-wheeled cars such as the Morgan 3-Wheeler are often classified as cars rather than motorcycles. Generally, the motorcycle classification will require passengers to sit behind the driver, whereas in the car classification, at least one passenger is able to sit abreast to the driver