Abstract: Efficient human-powered or human-power assisted energy generation and transmission system adapted for use with vehicles. The present invention can be utilized to achieve overall energy transmission efficiency superior to mechanical drives that utilize chains and sprockets or other mechanical drive mechanisms. The present invention can completely eliminate the need for multiple sprockets and the associated shifting mechanisms presently used in most bicycles. By utilizing high efficiency, light weight, direct-drive generators and motors, and an input controller, coupled with an efficient energy storage device, the present invention can reduce the overall weight and complexities of mechanical power transmissions, while, at the same time, offer higher overall efficiencies. In addition, the energy output to the output drive device can be controlled, through profiling and with an output controller, to maintain constant output, independent of instantaneous input.