WHILE DRIVING THE 2018 ESCALADE ESV RWD ON INTERSTATE 87 NORTH YESTERDAY, DRIVING ABOUT 33MPH, THE ESCALADE SUDDENLY SWERVED LEFT AND SLID INTO THE MEDIAN AND THEN ROLLED OVER ON ITS ROOF. AFTER THE ACCIDENT, I NOTED I HAD RECEIVED DIAGNOSTIC ONSTAR EMAILS THAT MORNING WHILE DRIVING THAT THE VEHICLE STABILITRAK AND ANTILOCK BRAKE SYSTEM WERE EXPERIENCING ISSUES. I ALSO PHONED ONSTAR TODAY ABOUT IF AND WHEN THEY RECEIVED A CRASH NOTIFICATION. THE CRASH NOTIFICATION DID NOT OCCUR WITH ONSTAR UNTIL THE VEHICLE WAS TURNED BACK OVER, NOT WHEN THE CRASH OCCURRED BUT AN HOUR LATER. THE VEHICLE IS LESS THAN 60 DAYS NEW.