We have a local school bus that took a head-on collision at speed (bus traveling 45mph, oncoming pickup at 60mph) and treated the occupants very well. The bus was full of high schoolers, the pickup was driven by another high schooler. The bus driver took a break near the ankle and none of the students sustained anything more than bumps and bruises.
Now, a lot comes into play here - the bus outweighs the pickup by several times, so it has the momentum to absorb the oncoming momentum and keep moving. But it's certainly not like hitting a flying bug. All that energy from the truck headed the opposite direction has to go somewhere, and it slows the bus dramatically in an instant. And these are high schoolers - no matter how many times the driver reminds them to sit down, sit correctly, they just won't. And even after all that, with no one besides the driver in a seatbelt, the students were all OK. (To satisfy curiosity: the driver of the pickup took serious injuries of which none were life-threatening; he spent two days in the hospital. He'd gotten impatient driving behind a tractor/trailer and decided to pass immediately after a curve without checking the lane first. This was a two-lane state "highway" and he was indeed in a zone that allowed passing.)
Then there's the Really Bad Accidents where the bus ends up on its side or upside down. Seatbelts are designed the hold under stress-- the button becomes near-impossible to operate and release. Smaller children will require the assistance of an adult. And there's ONE on the bus. With 50 kids. They make a safe belt cutter that a driver can carry, but now the driver has to visit every seat with multiple belts, cutting kids free, supporting them so they don't fall. This is not a scenario I'd care to have enter reality.
I can't speak to every seat belt buckle - but I went off a 20' foot cliff in a 70's sedan of some kind. (Grandmother was driving, she fell asleep). The seat belt left a perfect imprint of a bruise, down to the stitching on my chest and waste, but I (and my grandmother) had absolutely zero difficulty popping the seatbelt. The fall when we popped them wasn't that far, as 3/4 of the car had crushed.
Both of us walked away without a single injury other than the bruises from the seat belt. I've worn them religiously ever since that day.
> The seat belt left a perfect imprint of a bruise, down to the stitching on my chest and waste
One of the serious accidents I was in (my grandmother turned a corner very slowly and the other driver was going 130km/h, with a pregnant lady in the passengers seat) did the exact same thing to me. I also got a black eye; apparently right as the accident happened I entered the brace position so quickly I hit my eye socket on my own knee!
Are you sure the button becomes difficult to use? I might be very wrong here, but I'd at least hope that "release easily even when hanging upside down" might be a design requirement of the average safety belt buckle. Perhaps this is why aircraft belts have very different buckles than car belts? Can anyone provide more detail?
I'm not sure the claim is true. I only have one personal experience to base this on (fortunately) but I was in an accident as a passenger in a Jeep Wrangler which ended up upside-down on its roll-cage. Both the driver and I were hanging from our belts and had no problem undoing the buckles. We had to do it one-handed with our other hand trying to support ourselves so as not to drop on our heads after releasing the buckle. Click, release, just like normal.
I was in a severe single car accident in a 80s era truck, where I ended up rolling many times down into a ditch, and finally resting upside down. Seat belt did not release, the button was just solid, and I had to hold my body up to un-catch the strap ratchet so that it would relax, and I could wiggle out. In the whole event, the hardest part was kicking out the driver side window to get out of the cab.
The only part that saved my life was that I had stacked a bunch of HP servers right behind the driver seat, the rest of the cabin was completely crushed in ;-)
(Edit: I will never own a 4x4 or any high center of gravity vehicle which doesn't have a roll cage ever again. The day after the accident, I was sitting at the junk yard looking at the mashed ball of metal which used to be my truck, I couldn't believe I walked away without a scratch.)
Now, a lot comes into play here - the bus outweighs the pickup by several times, so it has the momentum to absorb the oncoming momentum and keep moving. But it's certainly not like hitting a flying bug. All that energy from the truck headed the opposite direction has to go somewhere, and it slows the bus dramatically in an instant. And these are high schoolers - no matter how many times the driver reminds them to sit down, sit correctly, they just won't. And even after all that, with no one besides the driver in a seatbelt, the students were all OK. (To satisfy curiosity: the driver of the pickup took serious injuries of which none were life-threatening; he spent two days in the hospital. He'd gotten impatient driving behind a tractor/trailer and decided to pass immediately after a curve without checking the lane first. This was a two-lane state "highway" and he was indeed in a zone that allowed passing.)
Then there's the Really Bad Accidents where the bus ends up on its side or upside down. Seatbelts are designed the hold under stress-- the button becomes near-impossible to operate and release. Smaller children will require the assistance of an adult. And there's ONE on the bus. With 50 kids. They make a safe belt cutter that a driver can carry, but now the driver has to visit every seat with multiple belts, cutting kids free, supporting them so they don't fall. This is not a scenario I'd care to have enter reality.