The present invention involves a vehicle for passengers having a passenger safety system. The system has a crash sensor, a vehicle seat with a weight sensor assembly, an air bag and an air bag controller. The crash sensor is capable of providing a signal when the vehicle experiences an impact force of a predetermined magnitude. The vehicle seat is capable of supporting a vehicle occupant, with a seat frame member attached to a vehicle floor pan. The seat frame member has a rigid end and a resiliently flexible end, the resiliently flexible end able to resiliently deflect with respect to the vehicle floor pan upon experiencing a force due to the weight of the vehicle occupant. The sensor assembly has a cantilevered beam, a fulcrum, and a sensing device. The cantilevered beam has only one point of fixed attachment for connecting to the vehicle floor pan and the seat frame member, and is capable of resiliently deflecting upon experiencing a load force and capable of returning to its pre-load orientation after said load force is removed. The fulcrum is located beneath the free end of the cantilevered beam so as to prevent the beam from permanently deforming under extreme loading conditions. The sensing device is located beneath the cantilevered beam and is adapted to provide a signal when said beam is subjected to a load force of a predetermined magnitude. The airbag is suited to rapidly deploy and provide protection to the passengers when the vehicle experiences an impact force of a predetermined magnitude. The airbag controller is capable of interpreting signals from the crash sensor and sensing device to determine whether to deploy the airbag when the vehicle experiences an impact force of a predetermined magnitude.