MY DAUGHTER WAS ON A 2 LANE STRETCH OF I-15 HIGHWAY SOUTHBOUND, APPROX 7 MILES NORTH OF LASVEGAS NV. SHE WAS IN THE LEFT LANE SLOWLY CREEPING BY A 18 WHEEL RIG W/TRAILER. SHE WAS DOING 74 WITH CRUISE CONTROL AND WITNESSES SAY THE RIG MUST HAVE BEEN DOING 73MPH. HE VIOLENTLY TURNED INTO HER LANE CAUSING HER TO DO EVASIVE MANEUVER LEFT AND BRAKE HARD SKIDDING INTO THE SOFT SHOULDER THEN SPINNING CLOCKWISE CROSSING TO THE RIGHT SIDE HITTING A SMALL SHOULDER ELEVATION CHANGE WITH BOTH DRIVERS SIDE WHEELS, CAUSING A DOUBLE ROLL OVER AND A CARTWHEEL LANDING ON THE TRUNK, THEN COMING TO A REST ON THE ROOF. NOT A SINGLE AIR BAG DEPLOYED! SHE SUFFERED MULTIPLE BLUNT HITS TO THE HEAD FROM HITTING AGAINST THE DOOR, SHE HAS A CONCUSSION WITH SPRAINED SHOULDER AND ANKLES. GRANTED SHE SHOULD BE IN MUCH WORSE CONDITION BUT WE ARE GRATEFUL SHE HAD HER BLANKETS AND HER DOGS BEDS THAT FLEW FROM THE BACK SEAT TO THE FRONT HELPING TO KEEP HER PADDED FROM EVEN MORE TRAUMA. I FEEL THAT A SIDE CURTAIN AND STEERING BAG SHOULD HAVE DEPLOYED. IS THIS A FLUKE THAT TOYOTA ENGINEERS MISSED? BECAUSE NO PARTICULAR CORNER WAS IMPACTED? THE ROLLOVER IMPACTS WERE AT THE WHEELS, JUST ABOVE BOTH BUMPERS AND THE ENTIRE ROOF AREA.