The EMBRIO is a robotic unicycle announced by Bombardier in 2003; it is currently only a conceptual design. If produced, it would not be available until 2025.
The EMBRIO is designed to be a hydrogen fuel cell-powered motorized unicycle capable of reaching highway speeds. The rider would control the vehicle using triggers mounted on handle bars. One would control acceleration, and the other would control braking. To turn, the rider would lean, much like a motorcyclist.
The balance would be similar to that of an inverted pendulum, such as a unicycle. However, in place of the balancing skill a unicyclist must learn in order to ride, the Embrio would utilize an internal gyroscope to keep the rider stable, even at high speeds. //Wikipedia
