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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?

#51

Post by Someone »

kcolford wrote: post #19
JoeAltmaier wrote: post #17

Earlier quoted context omitted.

Drive the largest vehicle you can. When in a collision the momentum is converted to crushing force, you want to be in the less-crushable vehicle. Hey this may be an unpopular choice, but it is the one with the biggest safety impact! And that was the question.

Correction: you want to be in the vehicle with the most crushable distance of material. That way the force is spread out more over time and there's less going through your body at any moment.

That’s not the entire story. If you value your health over that of all others, you will want to crush the car the others are driving in over its full length before the crushing of the parts of your own car where you are sitting starts.

That’s where having the sturdier car can help.

You also will want to be in the car that decelerates less briskly. That’s where, in collisions with movable objects, having the heavier car helps.

A heavy car without crumple zones from the 1950s that could kill you when hitting a wall at 20 km/hour might still be the safer car in a head-on collision with a much smaller car with a few meters of crumple zone (cars from the 1950s were incredibly unsafe, so I think this would require extra-ordinary circumstances)

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

#52

Post by ryanianian »

wscott wrote: post #30

The article reminds me of a story from a friend that was an engineer at a major water heater company. Modern electric water heaters are already fairly efficient, but every model gets tested by the government to be given an efficiency rating. The test consists of replacing the anode with a rod that has a series of temperature probes to measure the water at different levels in the water heater. Since water would form l…

Isn't this a symptom of the exact testing procedure being a white box that rarely changes? Many students would score 100% on the ACT if the entire question and answer set were widely published.

Also that seems like a silly test. Couldn't you just measure the differential after mixing? TFA also mentions it, but noise is also a factor. For the water-heater example, the limited number of probes introduces a known amount of potential variance.

Rather than a straight % efficiency, a more useful number to report would include the confidence interval - Its 99% ± 3%. Consumers can't do stats but at least it's more honest. TFA touches on this but doesn't draw any conclusions other than "we need to look at the source data and do our own analysis".

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

#53

Post by Merrill »

>For a long time, adult NHSTA and IIHS tests used a 1970s 50%-ile male dummy, which is 5'9" and 171lbs. ... >For reference, in 2019, the average weight of a U.S. adult male was 198 lbs and the average weight of a U.S. adult female was 171 lbs.

So the average mass of the American male has increased 15% in 50 years! No data on whether he is taller, but I'd bet the BMI has gone up.

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

#54

Post by kube-system »

andykellr wrote: post #26
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…

This reminds me of the fact that my grandmother who recently passed away at 96 refused to make left turns. She stopped driving years ago, but before she did, my father would always help her find a way to get to the pharmacy, the grocery store, church, and family and friends houses making only right turns. Sometimes she went miles out of her way.

At what point does the risk of the extra miles on the road outweigh the risk mitigated by avoiding left turns?

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

#56

Post by dangus »

ghaff wrote: post #35
dangus wrote: post #27

Earlier quoted context omitted.

The way to make yourself safer is to move to one of the few American cities and towns with walking and transit-oriented development. Seriously! You'll spend a fewer hours in the car risking car accident death. A family can easily downsize to one car or less. You'll also spend more time getting light exercise by walking to the bus/train, walking to the store, walking for enjoyment. You'll also save from no longer buyi…

I think it's hard to generalize that living in Manhattan without a car is safer and healthier than living in, say, Vermont with one--especially if you rent cars for weekend and other vacations. Depends of course on location, lifestyle, commute, etc.

Yes you’re right, and a big factor I didn’t think of is pollution.

The car accident death rate may be low enough that it’s really not worth mitigating against.

But also, I don’t mean Manhattan specifically. When I say “city” maybe you are thinking high rises. A neighborhood with predominately 2-4 story buildings can be incredibly walkable. You just have to stop designing everything to accommodate cars ahead of all else.

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

#57

Post by hpkuarg »

Merrill wrote: post #53

>For a long time, adult NHSTA and IIHS tests used a 1970s 50%-ile male dummy, which is 5'9" and 171lbs. ... >For reference, in 2019, the average weight of a U.S. adult male was 198 lbs and the average weight of a U.S. adult female was 171 lbs. So the average mass of the American male has increased 15% in 50 years! No data on whether he is taller, but I'd bet the BMI has gone up.

Over 70% of adult Americans are overweight or obese, according to BMI. Of course, BMI is an imperfect measure, but you're quite right to bet on the average American male having gotten fatter, not taller.

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

#58

Post by strict9 »

Whenever metrics are instrumented that measure productivity, safety, quality, or efficiency, the metrics and metrics alone are what matter, not the over arching goal.

Whether it's car crashes, fuel efficiency, lines of code, completed tickets, OKRs, or anything else, players in the system adjust to optimize output for the evaluated metric.

A tale as old as time.

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

#59

Post by kube-system »

nradov wrote: post #48
nostrademons wrote: post #29

Earlier quoted context omitted.

An interesting instance of the self-selection problem seems to show up if you select small 4-door 2017 cars. The Nissan Juke 2WD has a death rate of 12; the 4WD version of the same car has a death rate of 65. I have trouble believing that there's a significant difference in the cars themselves, so it seems likely that people who would buy a 2WD small SUV are a significantly different demographic than those who would…

The same discrepancy appears in the 2014 data as well so it's probably not a statistical fluke. Maybe there's a real design flaw in the Juke 4WD model?

The person is not suggesting it's a statistical flaw -- but that it's a self-selection bias.

Hypothesis: The people who opt to spend more for a 4wd version are people who know they will use it because they operate the vehicle in inclement conditions, and/or they are uncomfortable with their ability to operate a 2wd vehicle in those conditions and/or they do not have the option to stay home when the weather is bad.

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

#60

Post by EamonnMR »

blakesterz wrote: post #6
gorgoiler wrote: post #4

Volvo was always marketed as a safety product years ago. Seatbelts, seatbelt warning lights, airbags, and daytime lights — a requirement in Sweden — all spring to mind. I had assumed that Volvo lost that edge this century so it’s good to see them at the top of the list.

I just took a quick look at Consumer Reports for Vovlo's reliability and they're not great. A couple were even bad. If my memory is right, this has been the case for a while. It looks like maybe Volvos are safe, but not super reliable I guess?

Very nice engines if you put oil in them but supported with expensive, fragile electronics.
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