There are a variety of three-wheeled vehicles that may be used on the roads. Some three-wheeled motorcycles, known as trikes, are built from ordinary motorcycles using conversion kits. Factory-built three-wheeled motorcycles are also being designed by manufacturers. These vehicles may have one wheel in front and two in the back, or the opposite, sometimes referred to as a "reverse trike."

Even if they have three wheels, however, trikes and three-wheeled motorcycles are still treated as motorcycles by the National Highway Traffic Safety Administration (NHTSA), a Federal authority responsible for motor vehicle safety.

The NHTSA considers any motor vehicle with a seat or saddle and no more than three wheels to be a motorcycle. As a result, insurers generally issue motorcycle insurance to cover three-wheeled motorcycles and converted trikes.

Meanwhile, an autocycle is a type of three-wheeled vehicle that shares some features with cars, according to the American Association of Motor Vehicle Administrators (AAMVA). For example, autocycles typically have a steering wheel, and the operator sits in a seat similar to a car seat. In some autocycles, a passenger may be able to sit beside the driver. Some autocycles are open-air vehicles, like a motorcycle; others have an enclosed cabin, like a car.

Like trikes and three-wheeled motorcycles, the NHTSA treats an autocycle as a motorcycle. Insurers typically issue motorcycle insurance policies for open-air autocycles. However, in some states, enclosed autocycles may be covered by insurers under an auto insurance policy.

The National Conference of State Legislatures explains that some states recognize autocycles as a distinct kind of vehicle — neither a motorcycle nor a car. As a result, laws may vary by state about what kind of training or license is needed to drive an autocycle, and whether the driver and any passengers are required to wear a helmet. Review the laws in your area to make sure you meet the state's requirements.