Both BSMS/LCAS is determined to warn driver about approaching objects from vehicle rear and sides in range of approximately 3-10 meters.  The system provides driver precautions to vehicle lane changing and blind spot monitoring.
While some products include rear passenger traffic alarm and back-up alarm features.  RPTA warns rear passenger of moving traffic before opening doors, via warning indicators mounted on B pillar.  Back-up alarm warns about obstacle and distance when backing up the vehicle.