While no consolation for those who have had the exploding sun/moon roof experience, in the great scheme of things they are exceedingly rare given the proliferation of makes, models and years that are suspect, counting in the millions or perhaps 10's of millions of vehicles.
According to Consumer Reports:
- The first reported incident in the NHTSA data base involved a 1995 model.
- Between that time and the Consumer Reports story in 2017, there were 859 complaints filed with the NHTSA involving 35 brands and 208 models.
- Even if you multiply those complaints by a factor of 10 they are still exceedingly rare.
- Consumer Reports identified a spike in such incidents around 2011-2012 with the proliferation of panoramic sun roofs.
If you throw out the panoramic sun roofs, including the notorious 2012 Hyundai Veloster and Hyundai/Kia in general, the incidents are that much rarer.
Different manufacturers have responded differently: recalls, class action settlements (Hyundai), switching to laminated glass, other changes to manufacturing or design, or flawed glass cause determination. I see no evidence that Mazda has attested to any flaws, alterations or made claims of responsibility. Then again, Mazda has not been high on the hit list (and didn't even register in the 2017 Consumer Reports analysis). It is easy to exagerate the extent of the problem from a small handful of anecdotes. That doesn't mean they didn't tweek something here or there on one generation of one model or another along the way but the fact remains Mazda is low on the list of culprits perhaps specifically because they avoided panoramics in their designs.
So, how does one account for a small handful of incidences among a very large sample size of things that are identical from all appearances? The most likely answer is there is no one single cause but rather multiple factors unique to that particular vehicle, one or more of which may be environmental in the moment.
Perhaps, to take one speculation, Mazda or otherwise, repeated expansions and contractions from heat and cold introduce a weakness in the glass because the frame or glass design or manufacturing did not take that sufficiently into account. But that's not enough with many vehicles so produced with few exploding. Perhaps a flaw was introduced into that particular piece of glass. Or perhaps an unseen and unheard pebble then strikes a weakened piece of glass at a particular angle at a particular temperature while the barometric pressure in the vehicle is at a certain level or some other unique environmental whatnot in the moment as a preciptating cause. If no correlation of causes among the few incidences of a make and model can point to a specific cause or set of causes how are you going to fix it? You can't fix something if you don't know how it gets broken.
Now, Mazda (or some other maker in a similar situation) could switch to laminated glass as a precaution. At least one did, I can't recall which. Maybe it breaks just as often but doesn't blow shards over people and scratch everything in sight. There are a lot of things manufacturers can do differently to resolve a wide range of issues to err on the side of caution but it comes down to frequency, consequence, cost and impact on brand awareness. So far, nobody has been killed or seriously injured by an exploding sun roof in any make or model up through 2018 reports, and the Congressional hearing on the matter came to nothing I can see other than putting manufacturers on notice that they are on the radar if the matter gets worse.
I've owned one convertible and one vehicle with a sun roof. After the novelty wore off, I found I perferred not being wind blown, not having the sun beating on my head, while considering the absurdity of running the climate control with the car open to the outside. But these are matters of personal preference. If I had to buy a sunroof because it came in the car/trim at the price I was targetting I'd consider it a cost of doing business so to speak. That was the case with a 2006 Accord EX-L V6. After trying it a few times because it was there, I'd open it only around once per year just to make sure it was still working and not sticking. But that's me.
When looking at the data in it's entirety, about the only worry to be considered with a sunroof in an existing car or pending purchase might be with a panoramic one. Even then the odds of an incident are very low. In a world full of risks and worries if you care to go looking under rocks for them, this would still be low on the list.
Again, that's no consolation to the rare owners who experienced the problem, suffering panic, minor injuries, inconvenience and cost.
