Panoramic Glass Roofs. Are they safe.

Jamie_Carter

AdrianC wrote: »

Laminated glass is safe, as is toughened - but neither is 100% perfectly safe. Toughened will, as has been said, shatter into lots of small pieces, like gravel. BUT laminated has give in it. In a hard front-end crash, the head of an unbelted occupant can go through a laminated windscreen. The shoulders don't. Then they slump back, inside the car, pulling the windscreen back. The hole they've created then closes up on their neck, causing thoroughly horrible and usually fatal injuries. As you can imagine, in a heavy roll-over the same could easily happen with a laminated roof. In some crashes, a toughened glass roof could be safer by shattering than a laminated one. It'd also be easier for emergency services to get injured occupants out through.

But these are massively rare edge-cases. The odds of a panoramic roof being a safety issue are negligible - probably smaller than the risks from an opening sunroof.

Laminated has no more give than any other glass. But in most impacts it holds it's shape due to the fact that it is made up from two sheets of glass with a layer of plastic sandwiched between. The advantage when being used as a windscreen is that you don't lose your whole windscreen just from an impact from a small stone.


In most modern cars (without panoramic roofs), the glass provides up to 30% of the structural strength of the upper part of the vehicle. This would be a far higher percentage with a panoramic roof. So when a car rolls over the chances are that most, if not all of the glass will break leaving little protection for the occupants from anything that the vehicle may slide over, or come to rest upon. Manufacturers have attempted to combat this by using boron steel in many of the posts. But this creates huge problems for the fire service, as even their most powerful cutting equipment struggles with boron steel.


So in my opinion a metal roof gives far more protection than a glass one.

Headly

Jamie_Carter wrote: »

So in my opinion a metal roof gives far more protection than a glass one.

I agree with this. I've been looking at the pros and cons of panoramic roofs for several years now as various members of our family have changed their cars.

It seems that all of us have become less convinced over time that a panoramic roof is a necessarily a good choice, for several reasons including being prone to chips and other damage, risk of shatter failure, cost of repair, and safety issues (a steel roof might dent but at least it's more likely to stop sharp objects entering the cabin in the event of a roll-over or anything falling onto the car, such as tree branches - there's plenty of dead wood falling from trees overhanging the roads around where we live).

Of course I accept that in most cars we're surrounded by glass and that a windscreen presents a similar risk. But I'd prefer not to add to that risk. We all know that even windscreens break, sometimes with disastrous consequences.

My real gripe is that manufacturers (e.g. Honda, Nissan, etc.) have for a while been including parnoramic roofs on higher spec models as a standard item rather than an option, making their vehicles an impossible choice for purchasers who want a higher spec model, e.g. with leather seats, but who specifically do NOT want a panoramic roof.

I'd like to see panoramic roofs being offered as an option to give customers who don't want one more freedom of choice. Might encourage more sales for some manufacturers too, come to think of it, as clearly not everybody likes or wants a glass roof over their head.