For my commodities, I just have to design and engineer around the packaging space taken up by moon roofs so I am not schooled on this issue. I can see though that the glass panel mounted to a roof directly exposed to the sun could see some huge differentials between outside surface and inside surface on a hot summer day when the AC is running full blast in the interior. Now add some torsional twist during that exposure, I could see where it could pop.
I'll be looking for more data on these incidents and you've hit the two thoughts I'd have as major contributors.
Where are these incidents happening... Houston and Phoenix... extreme heat!
Detroit and Flint... rough roads and torsional twist are likely!
Had these vehicles been in some kind of prior crash?
Odd looking at the 2 Ford vehicles... The Focus is the smallest vehicle in the Ford lineup (I guess the Fiesta is smaller but I don't know if they have a moon roof) and the Edge is by far the largest moon roof that I am aware of. They've built a lot more Focuses over the years but probably a much higher percent of the Edges have moon roofs. The Focus moon roof would be probably 1/8th or even a 1/10th the square area of an Edge roof but I'm sure at 75 mph over the same road the Edge will ride much smoother...
lots and lots of un answered questions
