Four-Wheeled Motorcycles Edit
The Street-Legal K-Pteron

Designed by Alain Deveze, the K-pteron is part motorcycle, part sidecar, and part quad. The front and side wheels all turn as one to provide a balanced ride. It sort of looks like a lawnmower or perhaps a giant set of training wheels to me. Other than stability, I’m not sure what the advantage is over a traditional motorcycle.