The main functions of locking systems in vehicles are to protect the vehicle and luggage against theft and to ensure the safety of the occupants while driving. Basic models consist of the door lock, an inside door actuator and an outside door actuator. Depending on the model, outside door handle sensors, child locks, alarm systems and immobilisers are available. Modern crash locks enable the vehicle doors to be locked automatically in the event of an accident, ensuring that the occupants are not thrown out of the vehicle or put at additional risk by doors bursting open. Depending on the model, acoustic-visual displays of the locking status, remote controls and modern keyless entry systems that replace the previously obligatory key with a chip card are available to increase operating convenience. Locking systems are integrated by OEM into door systems, tailgates and boot lids.