I was driving on the freeway at 70mph, the indicated speed limit. It was cloudy, drizzling rain. No large vehicles near me. All of a sudden it sounded like a gunshot went off right above my head. I had the panoramic sunshade closed so I couldn't see anything, but my first thought was that the glass of the panoramic sunroof had shattered. After 5 more minutes of driving (so I could safely get home), I parked the car and stepped out of the door and looked at the roof. Sure enough, the front of the two pieces of glass had shattered right in the middle, about 150 square inches open to the sky, and dozens of pieces of broken glass had fallen in between the interior sunroof shade and where the glass was supposed to be. Thank goodness I had the shade closed, otherwise the pieces of glass would have landed on me and my girlfriend (who was sitting in the passenger seat.) There was no hail, no lightning, and no loose rocks from any vehicles in front of me. It was about 82 degrees Fahrenheit, so not abnormally warm.
NHTSA ODI 11478019