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This is the part that gets me: The Institute’s results also demonstrate the exceptional strength of Model 3’s all-glass roof, which is supported by a very
by SEJeff 7y ago
This is the part that gets me:
The Institute’s results also demonstrate the exceptional strength of Model 3’s all-glass roof, which is supported by a very strong metal body structure and helps protect occupants in roll-over crashes. During testing, the car’s roof was able to successfully resist more than 20,000 pounds of force – that’s more than if we placed five Model 3s on top of the car’s roof at once. And, the roof earned a higher strength-to-weight ratio score than any other fully electric vehicle that IIHS has ever tested.
It takes the weight of ~5 Model 3s ontop of a single one for the glass roof to shatter. That's good engineering.
- mc32 7y agoIn a rollover the glass might encounter a sharp point (ala “ninja rocks”) which exerts impact on a very small area causing failure, no? Or is their glass capable of absorbing these impacts?
- SEJeff 7y agohttps://www.iihs.org/ratings/about-our-tests#roof-strength-test https://www.iihs.org/ratings/about-our-tests#roof-strength-t...
- mc32 7y agoThanks that’s good information. I still have a concern in that it appears this is a controlled pressure (it’s not a sudden violent impact), if it is a sudden violent impact then it’s not expressed that way to me. Metal gives and then fails. Glass gives minimally, and depending on tempering, can fail very, very quickly.
- SEJeff 7y agoBut it is safety glass, and the roof is still re-enforced with metal.
- hanniabu 7y agoI also suspect this isn't a real world value because if you find yourself in an upside down car, chances are it's because you were in an accident. This means the vehicle likely acquired some damage and therefore would likely have a compromised support structure for the glass.
- MFogleman 7y agoRollover crashes are generally pretty safe assuming the roof doesn't collapse and squish you to death, and you are wearing your seatbelt. The energy dissipates without you suddenly coming to a stop like if you hit a tree. Most of the damage will be from broken windows/debris causing cuts/scratches. If you are not wearing a seatbelt, you run the risk of being ejected from the vehicle, and the higher risk of being 'partially ejected' from the vehicle, which is often worse. I personally observed only 1 vehicle where the roof caved in on rollover (I believe it was a mid 2000s mustang). If the driver had been a few inches taller, I imagine he would've been hurt pretty badly. The only other time I saw a roof collapse in wasn't from a roll over, but striking a tree roof first at a high rate of speed. The only rollover crash I ever observed that the driver couldn't walk away from was a rather fortunate partial ejection. The vehicle only rolled onto its side, pinning the drivers arm between the road and the door as it slid for a few dozen yards. The durability of the laminated safety glass should not be understated. A fire department's extraction team's approach is likely to be "cut through the glass with a circular saw". Granted, all of this is anecdotal, with a very small sample size. Either way, wear your seat belt.
- modeless 7y agoThe glass will almost certainly break in a rollover crash. But it's laminated safety glass, so it won't be dangerous. More importantly, the metal frame of the roof acts as a roll cage, and that's what IIHS tests the strength of. They're not really testing the glass. See pictures of a rolled over Model 3 here: https://electrek.co/2018/07/15/tesla-model-3-rollover-crash/ https://electrek.co/2018/07/15/tesla-model-3-rollover-crash/ The glass is broken but the rigid metal frame clearly protected the occupants from harm.
- anewguy9000 7y agoand how many model 3s does it take to shatter a metal roof? im not discounting that the claim is impressive, but from a purely safety point of view, wouldnt you expect even more significant forces on this thing in a crash?
- SEJeff 7y agoLots of vehicles have less crush strength than the Model 3, and most of them don't have glass roofs. If you recall... the NTHSA testing of the Model S literally broke their machine. The NTHSA said the Model S had the best rollover test (top impact from their machine trying to crush it) of anything they've ever tested. https://www.roadandtrack.com/new-cars/videos/a5238/watch-the-tesla-model-s-break-the-nhtsa-crash-test-scale/ https://www.roadandtrack.com/new-cars/videos/a5238/watch-the... To really answer your question, I've arbitrarily picked a few common vehicles with metal roofs. The IIHS says the Civic roof withstands 13,195lbs of force: https://www.iihs.org/ratings/vehicle/honda/civic-2-door-coupe/2019#roof-strength https://www.iihs.org/ratings/vehicle/honda/civic-2-door-coup... A Subaru Outback: 18,533lbs of roof strength: https://www.iihs.org/ratings/vehicle/subaru/outback-4-door-wagon/2019#roof-strength https://www.iihs.org/ratings/vehicle/subaru/outback-4-door-w... A BMW 3 series has roughly the same roof strength as a Model 3: https://www.iihs.org/ratings/vehicle/bmw/3-series-4-door-sedan/2019#roof-strength https://www.iihs.org/ratings/vehicle/bmw/3-series-4-door-sed... An Audi A5 is only 16,327lbs of roof strength: https://www.iihs.org/ratings/vehicle/audi/a5-coupe-2-door-coupe/2019#roof-strength https://www.iihs.org/ratings/vehicle/audi/a5-coupe-2-door-co... You get the idea!
- baybal2 7y agoOne moment you missed. Electric cars are very heavy, and their centres of mass tend to be right below the cabin. Having very strong pillars is pretty much a prerequisite for surviving a rollover in an EV.
- SEJeff 7y agoMost people tell me the BMW 330i is very comparable to a Model 3, and its curb weight is 3,582 to 3,764 lbs (per BMW). The Model 3's curb weight is 3,627 to 4,072 lbs (per Tesla). That isn't as big of a difference as I'd have expected.
- saiya-jin 7y agoStatic load is a nice number, but that's not what car safety test should be about - car crash is a rather violent dynamic event. I guess most common situation is rolling of the car, with possible stop at some wall with roof absorbing most of the impact. I am not sure tests of such an event would be still so favorable. Or to put it differently - that's an impressive achievement of a situation that will never happen to a Tesla driver. What about performance in crash situation that might actually happen?
- SEJeff 7y agoAsk literally anyone who's been in a horrific wreck in a tesla and walked away. They're incredibly safe vehicles. There have been some pretty insane examples of this, such as this one: https://www.autoblog.com/2016/05/06/tesla-model-s-crash-germany-report/ https://www.autoblog.com/2016/05/06/tesla-model-s-crash-germ...
- kalleboo 7y agoLiterally the definition of survivor bias.
- whenchamenia 7y agoNo doubt! I crashed violently, twice, at highway speeds, in tiny 80s economy cars. Im fine. They must be safe! /s
- kalleboo 7y agoYou joke but I've literally heard people make this argument about seat belts.
- SEJeff 7y agoI guess what I was attempting (and admittedly failing!) to say was that Tesla vehicles hold up very well in very bad wrecks. The cars have tons of driver assist / active safety features, but they also have a huge crumple zone due to not having an engine, and an exceptionally low center of gravity due to the battery. There are many cases where people walk away from bad wrecks in a tesla where they'd have been intensive care or worse in most vehicles.
- semi-extrinsic 7y agoWhere is that quote from? When I open TFA, I can't even find the word "glass" when I search for it.
- SEJeff 7y agoTesla's followup on this: https://www.tesla.com/blog/model-3-earns-2019-iihs-top-safety-pick-award https://www.tesla.com/blog/model-3-earns-2019-iihs-top-safet...
- weaksauce 7y agohttps://www.tesla.com/en_CA/blog/model-3-earns-2019-iihs-top-safety-pick-award?redirect=no https://www.tesla.com/en_CA/blog/model-3-earns-2019-iihs-top... Must have been moved from the Tesla press release to the institutes website press release.
- semi-extrinsic 7y agoMakes sense, the language in that quote sounds much more like a company press release. I would have been surprised if the IIHS actually said things like "the exceptional strength". On the contrary, IIHS didn't even find this fact important enough to mention in their press release at all.
- w-m 7y agoThe roof strength test is performed "by pushing an angled metal plate down on one side of the roof" (https://www.iihs.org/ratings/about-our-tests#roof-strength-test https://www.iihs.org/ratings/about-our-tests#roof-strength-t...). So it is the metal body structure that is tested here, not the glass in the center of the roof.
- black6 7y agoStrength and toughness are different properties in materials science. A ceramic mug is strong enough to support great amounts of weight, but it's not very tough. I would think toughness (and elastic modulus) plays more of a safety role in a roof than strength, because strength comes from the pillars.
- imeron 7y agoIt can also turn orange in certain conditions: https://www.google.com/search?q=tesla+orange+roof https://www.google.com/search?q=tesla+orange+roof
- SEJeff 7y agoIt is only the front part, and it is due to being polarized glass, which only manifests when the car is wet. I think it is kind of pretty actually (note that I own a Model 3).
- andrewmunsell 7y agoThe Model 3 has gone through several iterations of glass, and some builds actually have nearly the entire roof (including the back glass) turn orange in the rain, but I believe new builds actually have no coloration at all since they changed the glass again.
- cptskippy 7y agoIt isn't polarized, it's just an IR filter.
- gamblor956 7y agoNote: this quote is from Tesla, not the IIHS. It's marketing speak and isn't supported by anything in the IIHS's actual public announcement on their most recent vehicle safety ratings. Tesla has received flak in the past for misstating the results of IIHS and NHTSA testing.
- helpPeople 7y agoSome people seem more accepting of misinformation than others. The whole Mars thing + no 30k electric car after all these years have me immune. Tesla and musk are simply not trustworthy.
- thebluehawk 7y agoContext is important. Pretty much the entire aerospace industry is terrible at time estimates. SpaceX has accomplished some incredible things, so bashing them for "the whole Mars thing" when they are still hard at work on it seems premature and pithy. And as far as I'm aware they never promised a 30k car? They promised a 35k car, which you can buy today (you just have to email them or go in person and ask for it, it's not available online)
- hndamien 7y agoYou appear to be quite accepting of misinformation. Nobody promised a $30k electric car. It was $35k and they delivered it.
- helpPeople 7y agohttps://www.caranddriver.com/news/a27120534/tesla-model-3-lineup-changes-standard-range/ https://www.caranddriver.com/news/a27120534/tesla-model-3-li... From this year. There will be no 35k Tesla. Anyone who got one was merely lucky.
- hndamien 7y agoSo we agree that they delivered it.
- lucb1e 7y agoSo my phone may not yet have 5G, but my car can definitely pull 5G on its roof. Sure how many Gs one typically pulls during a car crash. 5 doesn't strike me as a lot, but of course this is specifically about force applied to the roof. I guess you have to not just roll but actually fall on top of it somehow. At any rate, some actual data would be great instead of being amazed at this marketing statement.
- thenewwazoo 7y agoWeight, a force in lbs, is not the same as g-force (m/s^2), which is an acceleration. You can't directly compare the two without knowing the time over which the acceleration occurs (and even then you only get an average force over time).
- ummonk 7y agoThe comment you’re replying to correctly used F=ma to impute the amount of sustained acceleration the roof could support.
- cptskippy 7y ago> It takes the weight of ~5 Model 3s ontop of a single one for the glass roof to shatter. That's good engineering. But that's not what it says at all. No where does it say the glass won't shatter. The Model 3 roof has two roll bars, one links the A pillars and the other links the B pillars. That's what's strong.
- prolepunk 7y agoI think the quote mischaracterizes static and dynamic load. Yes, the roof can hold 5 teslas stack one on top of the other, but this doesn't tell you much. More practical knowledge would be at what speed the car will fall on the roof before the roof collapses? 50km/h 70km/h 100km/h?
- eatbitseveryday 7y agoPlease do not use code formatting for quotes. It creates a terribly long unbroken side-scrollable box. > The Institute’s results also demonstrate the exceptional strength of Model 3’s all-glass roof, which is supported by a very strong metal body structure and helps protect occupants in roll-over crashes. During testing, the car’s roof was able to successfully resist more than 20,000 pounds of force – that’s more than if we placed five Model 3s on top of the car’s roof at once. And, the roof earned a higher strength-to-weight ratio score than any other fully electric vehicle that IIHS has ever tested.
- SEJeff 7y agoupvoting you for this. I thought it would break it into a block, and was wrong.
- kenhwang 7y agoThat's not even that impressive and pretty standard for the industry. The relatively pedestrian Mazda3 resists 18,239lbs, which is 6x it's weight. Just about every family sedan on the market does >5x body weight.
- peaktechisnow 7y agoIs the Mazda3 roof made out of glass?
- fucking_tragedy 7y agoWhat's being measured is the strength of the bars that make up the roof, not the glass.
- kenhwang 7y agoIt doesn't matter because the glass isn't load bearing. Sunroofs are even less rigid and safe than panoramic glass roofs and cars have been passing safety tests with those for decades.
- roland35 7y agoThe glass may be strong but it is probably not "tough" in a material science sense. Metals and plastics can absorb more force and impact without fracturing which is probably what you want in a crash: http://www-materials.eng.cam.ac.uk/mpsite/properties/non-IE/toughness.html http://www-materials.eng.cam.ac.uk/mpsite/properties/non-IE/...
- thetinguy 7y agoThat’s pretty much as strong as other cars in the class.