A VAN LOST CONTROL IN HEAVY RAIN MERGING ONTO A VERY BUSY INTERSTATE AND CROSSED 2 LANES OF TRAFFIC BEFORE ENTERING MY 3RD LANE. IT WAS PERPENDICULAR TO MY VEHICLE AS I STRUCK IT IN THE CENTER OF THE DRIVER'S SIDE AT APPROXIMATELY 65 MPH. MY DRIVER'S STEERING WHEEL AIRBAG DID NOT DEPLOY AT ALL. THERE WAS EXTENSIVE DAMAGE TO BOTH VEHICLES. I THEN SPUN AROUND AND SLID SIDEWAYS STRIKING A GUARDRAIL IN MY DRIVER'S DOOR WHICH CAUSED ME TO ROLL ON THE GUARDRAIL FOR APPROX 112 FT. BEFORE COMING TO REST ON MY WHEELS. THE SIDE CURTAIN AIRBAGS DEPLOYED BUT THE STEERING WHEEL NEVER DID. THE TRUCK SUSTAINED EXTENSIVE DAMAGE BEING A TOTAL LOSS.