A transportation device that has two or more wheel axes, auto-balance based drive control, a rider platform that is movable in fore-aft pitch angle, a motor assembly that is movable in fore-aft pitch angle, and a speed reduction mechanism. Various embodiments are presented that include a rider platform that better tracks the slope of an inclined riding surface, a speed reduction mechanism that may rotate in fore-aft (at least in part) with the motor assembly, and the use of separate fore-aft pitch angle and inclination sensors, among other embodiments. Possible forms of the transportation device include a scooter, a skateboard-like device, and a device with continuous tracks.