Power steering aims to make steering less strenuous for the driver. There are two types of power steering systems—hydraulic and electric/electronic. There is also a hydraulic-electric hybrid system possible.
A hydraulic power steering (HPS) uses hydraulic pressure supplied by an engine-driven pump. Electric power steering (EPS) is more efficient than the hydraulic power steering, since the electric power steering motor only needs to provide assist when the steering wheel is turned, whereas the hydraulic pump must run constantly. In EPS the assist level is easily tunable to the vehicle type, road speed, and even driver preference. An added benefit is the elimination of environmental hazard posed by leakage and disposal of hydraulic power steering fluid.