Driving on the highway, heard a very loud pop, followed by a crackling noise above us. Investigated and found the sunroof had spontaneously shattered. On the drive home, the sunroof glass collapsed into the car. The initial incident was very disruptive, and we were lucky that the sun shade was closed, which blocked glass fragments from falling on us. There are no signs of impact from any objects or rocks. There were no cars driving in front of us, and we did not drive beneath an overpass. There were no dents on the car. Photos of the glass after shattering but before collapse dont show a clear sign of an impact point. My best guess is a manufacturing flaw exacerbated by temperature changes. It was a very sunny day, and we had the shade open with cold AC blowing for 30+ minutes. The sun became a distraction, so we closed the shade. I think the heat then built up quickly between the shade and the glass, and caused the glass to shatter.
NHTSA ODI 11689028