Passive Safety Systems Most vehicles are equipped with two types of passive safety systems: seat belts (including seat belt reminder systems) and airbags (including occupant sensing systems).  ELESYS’ SeatSentry™ technology is the platform for all of its passive safety systems: SeatSentry™ – Occupant Sensing System Passenger Sensing System (PSS) Occupant Detection System (ODS) Seat Belt Reminder System (SBR) Airbag Sensors and Controllers (E-SRS)