1995 BMW E46 Tires Problems

ON 8/13/07, I WAS TRAVELING APPROXIMATELY 70 MILES PER HOUR ON NC HWY 52 NORTHBOUND (A 4 LANE DIVIDED HIGHWAY) WHEN I HAD A SUDDEN MASSIVE BLOW OUT OF A MICHELIN TIRE ON THE LEFT REAR OF MY VEHICLE, A 1995 BMW 325 IS. THERE WAS NO WARNING. THE TIRE WAS NOT LOW ON AIR PRESSURE AND DID NOT HAVE ANY PUNCTURE AS VERIFIED BY THE TIRE DEALERSHIP OWNER. THE TIRE IS A MICHELIN ENERGY PLUS MXV4, SIZE 205/60R15. IT HAS THE FOLLOWING LETTERING ON IT: DOT APTM W17X 2306. THE DEALER SAID THAT THE 2306 INDICATES THE WEEK OF MANUFACTURE. THE TIRE HAD 12,000 MILES ON IT. THERE WAS A COMPLETE SEPARATION OF THE OUTSIDE SIDE WALL FROM THE REST OF THE TIRE. WITH SOME STRUGGLE, I WAS ABLE TO MAINTAIN CONTROL. FORTUNATELY THERE WAS NO VEHICLE BESIDE OF ME AS I HAD TO UTILIZE BOTH OF THE LANES...