Tire Sidewall problems of the 2011 Toyota Prius

Since I purchased a 2011 Toyota Prius in December 2011 I have had to replace 2 irreparable original equipment yokohama avis s33 tires due to side wall damage. I am concerned that the side walls are not strong enough to resist potential hazards. This is part of yokohama case #[xxx] which included other concerns. I have rarely had a sidewall problem and never a flat tire with new tires. The first occurred at about 300 miles of use the next at 8300 miles, the approximate incident date. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).