A device for human conveyance includes front and rear wheels. The rear wheel interfaces to a sprocket/gear through a ratchet drive system allowing forward rotation of the rear wheel responsive to forward rotation of the sprocket/gear and allows free backward rotation of the sprocket/gear. The front and rear wheels are rotatably interfaced to a frame that keeps the front wheel at a constant distance from the rear wheel. A front end of an arc-shaped spring is affixed to the frame and a rear end of the arc-shaped spring has sprocket/gear teeth that are interfaced to the sprocket/gear whereas depression of the arc-shaped spring pushes the rear-end of the arc-shaped spring in a rearward direction with respect to the rear wheel and the sprocket/gear teeth turns the sprocket/gear in a forward rotational direction. A resilient member is disposed between the arc-shaped spring and the frame to absorb shock.