A vehicle .[.seat belt tension prediction.]. .Iadd.restraint actuator control .Iaddend.system .[.and method.]. comprises an accelerometer .[.having an output.]. .Iadd.that generates a .Iaddend.signal responsive to vertical acceleration of the vehicle, a .[.seat weight.]. .Iadd.force responsive .Iaddend.sensor .[.having an output.]. .Iadd.that generates a .Iaddend.signal responsive to the force exerted by a mass resting on the seat, and a processor .[.means.]. .Iadd.operatively coupled to the accelerometer and the force responsive sensor .Iaddend.for .[.calculating seat belt tension.]. .Iadd.controlling the actuation of a restraint actuator responsive thereto.Iaddend.. .[.The processor is provided with a plurality of inputs operatively coupled to the accelerometer output and seat weight sensor output. Suitable programming is provided to instruct.]. .Iadd.In one embodiment, .Iaddend.the processor .[.to.]. calculate.Iadd.s .Iaddend.the average mass .[.resting.]. on the vehicle seat and predict.[.the.]. .Iadd.s a .Iaddend.force .[.that should be.]. exerted on the seat .[.for.]. .Iadd.corresponding to .Iaddend.a measured level of vertical acceleration assuming zero belt tension. The processor then .[.compares the.]. .Iadd.controls the actuation of the restraint actuator responsive to a comparison of an .Iaddend.actual force measured by the .[.seat weight.]. .Iadd.force responsive .Iaddend.sensor with the predicted force .[.to determine seat belt tension thereby obviating the necessity of complex hardware in physical contact with the seat belt system.]. . .Iadd.In another embodiment, the processor controls the actuation of the restraint actuator responsive to a ratio of a measure of seat weight divided by a measure of vertical acceleration and by the average mass..Iaddend.