The airbag control unit detects and evaluates the severity of an accident and then triggers the appropriate restraint systems. Information is supplied to the unit by as many as six crash sensors. This includes acceleration sensors and a rotational speed sensor. The readings from these are used to evaluate and compare the signals from the other sensors. The crash signals are then sent to the airbag control unit and additional data systems to activate the hazard lights and interior lights, turn off the fuel pump and stop the engine. The restraint systems are also designed to achieve maximum effect according to accident type.