Lateral inclination angle detector for passenger-protecting device for use in automotive vehicle

This application is based upon and claims benefit of priority of Japanese Patent Application No. 2001-370401 filed on Dec. 4, 2001. A passenger-protecting device such as an air-bag system is activated upon detection of a vehicle lateral inclination angle exceeding a predetermined critical level. Such detection is performed by a lateral inclination detector having a pair of gravitational acceleration sensors for detecting a static road inclination and an angular velocity sensor for detecting a dynamic roll angle of the vehicle. Sensing directions of the pair of gravitational acceleration sensors are positioned to cross each other with a right angle and to make an angle of 45° with respect to a vehicle floor. The dynamic roll angle is calculated by integrating outputs of the angular velocity sensor. The vehicle inclination angle is obtained to summing up the static inclination angle and the roll angle. The passenger-protecting device is timely activated to protect passengers from overturn impact of the vehicle.