A vehicle that is propelled by as few as one actuator through a compliant drive train can move quickly on relatively smooth terrain and can climb obstacles. The body of the vehicle may consist of a single segment or multiple segments connected by articulating joints. The driving appendages can take different forms including legs or specialized legs with multiple spokes attached to a rotating hub. The driving appendages can be propelled by as few as one actuator. The driving appendages are each serially connected to their actuator(s) by a compliant device. The compliant devices permit relative motion between driving appendages that share the same actuator. A springably biased compliant device maintains nominal-desired phasing among driving appendages until one of them is forcibly perturbed. The phasing of the driving appendages, or gait, adapts to the terrain. Mechanical stops limit the excursion of the compliant device such that a new desirable leg phasing is reached for climbing large obstacles. The elasticity of the compliant device restores the phasing of the driving appendages to their nominal state when the perturbation is removed. Compliance in the driving appendages and feet smooth the cyclic motion of the body. Compliant feet conform to the terrain and provide improved traction. Steering mechanisms rotate the plane of action of the driving appendages.