A hybrid motor that made its debut on the F1 circuit will be used in London’s public buses to increase fuel efficiency. The technology called Gyrodrive is a high tech flywheel (a mechanism that stores energy as momentum) and harnesses power that is usually lost as heat. The way Gyrodrive works, is when the brakes are applied to a vehicle a traction motor that is attached to the axle engages and is used to slow the vehicle. The traction motor turns a carbon fiber flywheel that is enclosed in a vacuum. Then when the vehicle sets off it taps the energy from the flywheel to bring it up to speed before the motor kicks in. The Gyrodrive can spin at 36,000 RPMs and can send up to 120 kilowatts of energy back to the engine, which should boost gas mileage by 20%.