I WAS DRIVING MY FORD 250 ON A SLICK ROAD WHEN A PICK UP STOPPED SHORT IN FRONT OF ME. I WAS UNABLE TO STOP IN TIME HITTING THE REAR END OF THE PICK UP APPROXIMATELY 20-30 MPH. MY AIR BAGS DID NOT DEPLOY AND THE SEAT BELT ALLOWED ME TO SLIDE UNDER THE BELT CAUSING MY KNEES TO HIT THE DASH. OTHER THEN GOOD BRUISES AND MILD SORENESS I WAS FINE. THE OTHER PERSON WAS FINE AS WELL. MY SEAT BELT DID NOT ENGAGE AND I AM WONDERING WHY MY AIRBAGS DID NOT DEPLOY. THE GRILL AND RADIATOR WERE DAMAGED?