AIR BAG DEPLOYED WITHOUT WARNING AND NO IMPACT. DRIVER WAS DRIVING DOWN 2 LANE ROAD GOING ROUGHLY 25 MPH. ROAD SURFACE WAS SMOOTH AND FLAT (NO POT HOLES). IT HAD JUST STARTED RAINING. NO OTHER VEHICLES ON THE ROAD. AIR BAG DEPLOYED WITHOUT IMPACT TO ANY OTHER OBJECT AND WITHOUT WARNING. DRIVER SUSTAINED INJURIES TO HEAD, ARM, AND CHEST. *TR