An articulated steerable self-propelled vehicle has a support platform mounting a motive power source and sites at opposite sides of motive power source where an operator's feet can be placed to enable the operator to stand on platform and straddle motive power source. First suspension assembly on vehicle is pivotally mounted to platform in order to dispose and couple first ground surface contacting member spaced in first direction from platform, movable to follow the ground surface, vertically movable relative to platform to accommodate impact generated by uneven ground surface, and steerable horizontally relative to platform and the ground surface. Second support assembly on the vehicle is pivotally mounted to platform in order to dispose and couple second ground surface contacting member spaced in second direction from of platform, movable to follow the ground surface, and vertically movable relative to platform to accommodate impact generated by uneven ground surface.