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How well do cars do in crash tests they're not optimized for?

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Re: How well do cars do in crash tests they're not optimized for?

#291

Post by hansvm »

sokoloff wrote: post #184
hansvm wrote: post #159

Earlier quoted context omitted.

I've always found it a bit amusing how common this belief is, especially in snowier areas. Most people would be safer without 4WD/AWD -- less likely to oversteer around a curve, and less likely to drive aggressively because of a false belief that AWD will help you stop faster or have better control of your vehicle in low-traction conditions. It's still a really nice feature that has its uses, but most people I talk t…

The likelihood to oversteer depends on whether the 2WD alternative is front or rear wheel drive. RWD is more likely to oversteer on acceleration in slippery, turning conditions.

No argument here. That was my regional bias slipping in -- RWD is incredibly uncommon in the cold places I've lived except for pickups, and most people are aware of the potential dangers of RWD.

Re: How well do cars do in crash tests they're not optimized for?

#292

Post by catalogia »

duskwuff wrote: post #210
baxtr wrote: post #76

Earlier quoted context omitted.

Thanks! That’s really a great source. I am so glad I asked. Highlights: - Fishing seems to be quite dangerous!!?? - Swimming is less dangerous than living (all other causes)!

"Fishing" might include "working on an industrial-scale fishing boat", which is a notoriously dangerous line of work.

For some, "fishing" means "getting drunk on a boat, with no real intent of seeing a fish." Alcohol is a very common factor in boating accidents, somewhere between 15-50% depending on which source you look at. (I think the higher end of that range is likely closest to the truth.)

Re: How well do cars do in crash tests they're not optimized for?

#293

Post by viraptor »

Nasrudith wrote: post #240
alistairSH wrote: post #200

Earlier quoted context omitted.

I'm not sure that's an accurate description of VW's cheat. VW knew the parameters of the test (stationary car, no steering input, prescribed throttle inputs, etc). And they configured the car to pass the test. Water-heater engineer knew the parameters of the test (number and location of probes). And he configure the water-heater to pass the test. Same-same. In both cases, an engineering team willfully committed fraud…

One added difference is that the water heater. The intent may be deceptive but they provided what was asked for and what they claimed. It is almost malicious compliance. Dickish gaming and probably worth suing over but not sure if it is criminal fraud per se. It is like the joke about Soviet factory metrics for some item like nails. They set the quota on numbers and got useless ones better described as needles. They…

That kind of mentality was the joke in many eastern eu movies in the 80s. Pretty much the standard comedy in Polish movies from that time.

Re: How well do cars do in crash tests they're not optimized for?

#294

Post by adrr »

dublinben wrote: post #12
laegooose wrote: post #5

The whole car safety topic is very confusing. Car accidents is top1-top2 death reason in US for people in 20-40 age group [1]. Probably less in Europe but still one of the leading ones. I was thinking about how I can make myself safer. Which car brand/model is better? Which seat is better for passenger? How much riskier it is to drive during the night? In the rain? How dangerous is it to overtake on road with 1 lane…

You're right that there aren't meaningfully significant differences between car brands. Driving itself is just very dangerous. Other forms of transportation like buses, trains, and airplanes are orders of magnitude safer.[0] If you want to make yourself safer, avoid driving as much as possible. [0] https://injuryfacts.nsc.org/home-and-community/safety-topics...

Distance isn’t the best measure. It should be time of travel or trips. If we had a teleportation device that could teleport us to another solar system but had a 50% chance of killing the person, by using distance it would be the safest method of travel.

Re: How well do cars do in crash tests they're not optimized for?

#295

Post by the_pwner224 »

Marsymars wrote: post #268
nxc18 wrote: post #143

Earlier quoted context omitted.

Also worth considering is that anything after 2018 likely has intelligent crash prevention features. In addition to modern cars being much safer in a crash, the benefits of avoiding collisions altogether have to be worth it. I’ve been driving a car with the pre collision warnings, lane departure warnings, etc since 2017 and it has saved me at least once. There’s a concern about moral hazard with the new technologies,…

> Also worth considering is that anything after 2018 likely has intelligent crash prevention features. In addition to modern cars being much safer in a crash, the benefits of avoiding collisions altogether have to be worth it. I expect they're a net gain for the public, but that for an individual who's conscientious and never drives under the influence, tired, or distracted, that they're only marginally useful at bes…

Some distractions are inevitable and unavoidable while driving, even if you know not to get distracted.

Lane departure avoidance systems that been when you start to drift sideways are really annoying, but the preemptive braking stuff seems like a really good thing to have.

Re: How well do cars do in crash tests they're not optimized for?

#296

Post by moonchild »

dublinben wrote: post #12
laegooose wrote: post #5

The whole car safety topic is very confusing. Car accidents is top1-top2 death reason in US for people in 20-40 age group [1]. Probably less in Europe but still one of the leading ones. I was thinking about how I can make myself safer. Which car brand/model is better? Which seat is better for passenger? How much riskier it is to drive during the night? In the rain? How dangerous is it to overtake on road with 1 lane…

You're right that there aren't meaningfully significant differences between car brands. Driving itself is just very dangerous. Other forms of transportation like buses, trains, and airplanes are orders of magnitude safer.[0] If you want to make yourself safer, avoid driving as much as possible. [0] https://injuryfacts.nsc.org/home-and-community/safety-topics...

Why are buses safer? They drive on the same roads as cars.

Re: How well do cars do in crash tests they're not optimized for?

#297

Post by catalogia »

Sohcahtoa82 wrote: post #213
ohples wrote: post #163

Earlier quoted context omitted.

> Car accidents is top1-top2 death reason in US for people in 20-40 age group [1] Car crashes where the top 1-2. I am willing to bet most of those involved DUI, and therefore negligence, and shouldn't be classed as "accidents" #CrashNotAccident.

I don't have statistics to back it up, but I would be willing to bet money that at least 95% of crashes are from negligence with slightly less than 5% being from a sudden unexpected mechanical failure (Such as a tire exploding), with less than 1% being something you could truly call an "accident". The usual counter-argument is that the use of the word "accident" is a statement of intent, and outside of extreme road r…

> TBH, I'm not even sure if any crashes could really qualify as an "accident".

There are some. One that comes to mind is a freak rock falling off a truck in the opposing lane coming through your windshield. Possible negligence on the part of whoever loaded the truck, but for the victim it may as well be a lightning strike on a clear sunny day. Falling trees or things like that could do it too.

However, I think "car crashes aren't accidents" is probably close enough to the truth that it makes sense to use as a mantra in drivers ed (as my drivers ed teacher did.)

Re: How well do cars do in crash tests they're not optimized for?

#298

Post by elihu »

tpmx wrote: post #183
globular-toast wrote: post #161

Earlier quoted context omitted.

It is not the prisoner's dilemma at all. If everyone gets big cars then everyone is equally as safe. They don't all die. For crying out loud, people, I know it's stupid, I know it's wrong, but it's the truth. It's an uncomfortable truth that your downvoting will not change.

I think you're on to something. First: there's vehicle-to-barrier crashes (think trees, etc): Having a vehicle with a large well-designed crumple zone seems obviously good from a survivability POV. Second: there's vehicle-to-vehicle crashes: Is it really a zero-sum game? If a small car crashes head on with a large car, will the people in the small car suffer worse than if they crashed into another small car? To what…

If a heavy car collides with a light car head on at, say, 60mph, the heavy car might slow to 20mph whereas the light car might be pushed backwards at 20mph. So one car experience 40mph of velocity change in a short time interval, whereas the other experience 80mph of velocity change.

This is hypothetical; I don't know what real numbers from real collisions are like, but light cars are definitely at a disadvantage in that they can get knocked around a lot more. There's also the possibility of a light car getting pinned between a heavy car and an immovable object or another heavy car.

I don't think this is zero-sum: ideally, we'd all be driving around in large bubbles that weigh 200 pounds or less and have huge crush zones filled with styrofoam or something.

Re: How well do cars do in crash tests they're not optimized for?

#299

Post by dmurray »

ebg13 wrote: post #134
henryfjordan wrote: post #121

Earlier quoted context omitted.

Imagine the water heater company didn't know they were gaming the test. They first design a water heater and it gets a B- on the test. Being overachievers, they work hard and submit a second design that gets an A+. They might not realize that both heaters are basically the same with the only difference being some heating element spacing that works better for the test. Both times they submitted a legit design that was…

> Imagine the water heater company didn't know they were gaming the test. We don't have to. In this case we have clear admission of intent. The intent to deceive is what makes it fraud and not just being wrong.

There's no intent to deceive necessary in the water heater example. The water heater company could have sent it in with a note to the regulator saying "we moved the second element up, because we believe it will perform better on your test" and the regulator would likely just accept it instead of redesigning the test.

Also, for the water heating one, there's a plausible reason for the regulator to care about the discrete measurements rather than the total amount of thermal energy in the water. Hot water at the top of the tank is more valuable, because it's used first and less likely to be wasted, so you could wait it more heavily in a test. There's no parallel for the VW test cheating. No indication that's what happened here, of course.

Re: How well do cars do in crash tests they're not optimized for?

#300

Post by dmurray »

jodrellblank wrote: post #284
Gibbon1 wrote: post #236

Earlier quoted context omitted.

I think because with a modern water heater especially electric models the heat loss is so low convection often stops completely. So the water in the tank doesn't mix. I think you can get situations too where the water at the level of the heating elements gets hotter and hotter and the water away from it gets cold. My water heater strongly suggests adding a mixing valve for that reason.

> " water at the level of the heating elements gets hotter and hotter and the water away from it gets cold. " Eh? How come that temperature differential doesn't cause convection? The colder water being more dense and sinking down, the warmer water being less dense and rising up. If the heating elements aren't at the bottom, specifically for this reason, how come they aren't?

> If the heating elements aren't at the bottom, specifically for this reason, how come they aren't?

There are typically two heating elements, one near the bottom and one further up. You can use the higher one if you only need a half-tank of hot water.

I'm not sure if this is the complete answer to your other question, or if sometimes conditions are such that convection occurs extremely slowly despite a substantial temperature difference.

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