TRW uses its expertise in sensor technology to manufacture a product that offers a field of view that covers most of the blind-spot area around a vehicle.  If a moving object is detected within the specified zone a warning signal is issued. Mostly an optical indicator in the side mirror is used as a warning HMI. Vibration generators inside the seat cushion or inside the steering wheel are options for providing haptical feedback. Some systems include a Lane Change Assist (LCA) function. In this case the warning level depends not only on the position but also on the velocity of the approaching vehicle.