I had an idea about using a strong coiled band spring, like a watch spring, for the braking system on a bicycle. When the brake is applied, the outside of the coil connects to the wheel and the spring winds up as the wheel slows down. When the bike comes to a stop, it locks in place to prevent the spring from pushing the bike backwards. Now, the coasting energy is stored in the coiled spring. The center of the coil is attached to a sprocket that is attached to the wheel. When the brake is released, the coiled spring unwinds turning this center sprocket in the forward direction which also turns the bike's wheel in the forward direction. So, the coasting energy that the bike had before stopping is being used by the spring to push the bike in the forward direction when the bike starts up again. When the spring unwinds completely, the wheel continues to turn forward wratcheting past the center sprocket; the wheel turns free of the center sprocket. If this can be made to work for a bike, it might be possible to make it work for motorcycles and small cars. I consider this a metalurgy and mechanical enineering problem, which could be resolved by trial and error and experimentation. The right connections must be found and the right type of metal for the spring. Fixing the brakes might just involve installing a new spring.