Abstract: An apparatus for linearly driving a vehicle or machine. The apparatus includes a frame, at least one drive wheel, and at least one rotatable driver comprising a pulley or a sprocket, rotatably mounted with respect to the frame. Further, the system includes a flexible, elongated power transmitter comprising a belt, a chain, or a cable, the transmitter being mounted for reciprocating linear motion with respect to the frame and passing around and engaging the rotatable driver to rotate the driver in at least a first rotational direction. The apparatus also has a first and second pedal to engage the power transmitter in a first and second direction. The first and second pedals are mounted to the frame in a manner that permits only non-arcuate, linear reciprocating motion of the pedals with respect to the frame.