Spontaneously exploding panoramic sunroof: I was driving northbound on I-5 in Everett, WA, on 27 January 2023 around 7pm. It was clear, the road was dry, it was around 45 degrees, and there was medium traffic. We were going about 65mph. Just myself and my 4 year old daughter were in the car. With no warning and no visible reason there was a gunshot-like sound and then wind (and a crying daughter). I figured out that it was the rear panel of our two-panel sunroof and glass was sprinkling down. Luckily the sunshade roller was holding much of it. We pulled over and checked it out and that is it. Nobody was injured, but there was glass all over my daughter and in her car seat. facts: -2016 GL350 Mercedes; 59500 miles, excellent shape, two-panel panoramic sunroof (front sliding; rear fixed in place) -I have a Packasport 90 rooftop box on low profile Whispbars that covers the entire sunroof with only about a 1.5" gap over the rear glass panel -the box has been on the roof for at least 3 years and the sunroof has not been operated in that time -there have been no modifications to the car besides the rooftop box -it is very, very, very unlikely that a rock could've hit it (although the dealer and insurance don't really want to hear this) -the temperature was normal for January -the highway was smooth and clean and dry -the glass was cratered upward after breaking (may not mean anything) -I was not following a dump truck or a logging truck -I didn't see or hear any rocks or debris in the split second before the breakage My assessment is that the glass shattered of its own accord. I do not know why, but I have seen reports of this on the internet in auto forums.
NHTSA ODI 11508928