CONSUMER STATED WHILE DRIVING ON HIGHWAY AT APPROX 70MPH, THE LEFT REAR TIRE'S TREAD SEPARATED RESULTING IN CONSUMER LOSES CONTROL OF VEHICLE AND CRASHING. INSPECTION OF REMAINING 3 TIRES SHOW HAIRLINE CRACKS IN TREAD. VEHICLE IS A 1999 CHEVROLET SUBURBAN. TIRE INFO: B.F. GOODRICH 245/75R16 36K MILES ON TIRES ORIGINAL DOT NO.-??? TS