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 layers of different temperatures you needed measure at multiple locations to know the overall energy in the water. Then a series of water draws are performed with pauses between them and the total energy used is compared to the energy delivered.
Our engineer realized that if he could put the temperature layers at just the right locations then the calculations with the limited number of probes could be skewed. And this can be done by tweaking the height of the 2 heating elements. Just moving them a few inches.
The first time he tried this, an internal test came back at 101% efficiency. At little more tweaking and the test returns a consistent 99.x% that was respectable.
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".
The industry has made a bit of progress, surprisingly unprompted by regulations - female and child dummies came into circulation before they were required in tests. But overall, testing is still run against a tiny handful of body types which move 'realistically' in only a few regulation-guided respects.
The main reason the DOT standard is so bad is because its mired in bureaucracy and managed by a severely underfunded organization.
Though I'm not aware of a law stating that for any given principle there is an existing eponymous law.
... oh, wait: https://en.wikipedia.org/wiki/Stigler%27s_law_of_eponymy
The water heater was designed with the test in mind but functions the same regardless.
VW was clearly cheating whereas the water heater is taking advantage of known deficiencies in the test (is that cheating?).
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 to improve their sales figures.
The only differences are a bit pedantic. VW's "configuration" was more elaborate. But, both groups gamed the test.
Apparently it is common for cars to have a "test mode" bit, because they run on a dyno (only one set of wheels spin), and the car may disable certain traction control systems, etc.
VW changed the way other systems (the engine itself) function in this mode. So even if everything is exactly the same on the road (e.g. 30mph in a straight line for hours), the car will perform differently and have different emissions. You don't drive around on a dyno.
Optimizing for the test may go up to the line, but VW crossed it.
The VW engineers designed the car to do different thing while being tested vs used by consumers. While being tested, the emissions system was on. While being used by consumers, the emission system was entirely disabled.
The water heater engineers designed the water heater to do the same thing while being tested vs used by consumers.
If the water heater engineers designed the water heater to never turn on and keep the water at room temperature while being tested, ("works good boss, water heater efficiency is infinity percent") then yes, it would be reasonable to claim they did essentially the same thing.
I think the difference between what they did and this is only a difference in degree and not kind though, right?
In both cases there was an intentional design change to deliberately changed mislead a measurement, and the final product does not match the intended thing. Both adversarially directly cause the consumer's purchase to not be the intended item; no one gets a car that has emissions measured and no one gets a heater that has the efficiency measured.
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 wised up a bit and set the quota by weight next month and got one useless massive nail instead. It isn't even too far from the truth given actual management involved things like a train line circularly shipping coal between depots instead of retrieving from source or distributing to end users to boost their "metric tons transported kilometers" metric.
VW meanwhile had a covert illegal configuration while claiming mileage and lack of maintenancd urea. The claims are outright false - that it provides all three benefits instead of two of three.
The water heater runs the same regardless of whether it's being tested or is running normally in someone's home. Really, this test "cheat" exposed that the test itself was not measuring what it thought it was measuring; and hell, a manufacturer could accidentally cheat with their design.
The car would run differently if it detected it was in a test situation. In the real world, with a real driver, it would run in a way that would give different test results (if you were in a position to run the test while it's being driven).
"Cheating" a better efficiency rating is significantly less reprehensible than cheating a legal obligation which was legislated for public health and environmental reasons.
There are other differences here too, I think. The water heater trick is passive manipulation that stays in place at all times, which limits how far from "real" performance it can get. And per the story, it seems more like "teaching to the test" than "cheating". That is, Volkswagen consciously moved away from the mandate outside of testing. The water heater was (potentially) as energy-efficient as they could design, with the test score manipulated on top of that.
None of that makes it harmless - if "as good as you can make" doesn't hit standards without manipulating them, that's still a problem. But I do find it less galling than "intentionally worsens emissions outside the test bench".
The difference between the water heater and VW is the water heater manufacturer is providing a representative sample. And VW was not. It'd also be dubious to say that the water heater company is acting in bad faith. Where VW's bad faith rose to the level of criminal. On the other hand Volvo appears to be acting in strictly good faith.
Bad faith for a crash test would be crafting a silver plate model for testing. Reminds me that's what my uncle said the power supply manufacturer he worked for did.
While I agree that this particular water heater manufacturer was doing something shady in order to get the best score, at least they weren't selling a product that did something differently while under test conditions vs. in real-world usage. They merely realized that the test itself had wide error bars, and designed their heater to "err" in the positive side of those.
VW, in contrast, sold a product that lied to the testers about its emissions in order to pass certifications, while in real-world driving would behave in a way that would not pass muster.
And to me I think that's the key: VW's cars intentionally behaved differently depending on if they were being tested or if they were being driven in normal real-world usage. This water heater behaved the same regardless of whether it was being tested or was heating water in someone's home.
In a way I think of this in academic terms. The water heater manufacturer studied the SAT to learn what kind of questions were going to be asked. VW stole the answer key to the test and memorized it.
1. Actively detecting test and behaving differently. It's like stealing a test vs teaching to the test.
2. Lower stakes. Health issues are much more serious than inefficiency.
3. It affects the buyer. It's more acceptable for the buyer to be cheated than everyone around them.
4. People could have created these layers by accident. Favouring those who got lucky is unfair.
Honestly I think basically all my gadgets exaggerate how energy efficient they are, by tuning parameters for tests that don't correspond to the real world. My dishwasher has an energy efficient mode, the manual literally says it's just for compliance and recommends other modes. It's just a fact of life.
Your point about fairness and passive design is the one that makes me view these cases differently also. In the anecdote, the product being tested was the same one being sold, and there's no sign the heater was worsened to improve test performance. The designers just picked the best-scoring option among some reasonable configurations. (Frankly, once they noticed that issue, what were they supposed to do? Pick the worst-scoring, or pick the spec out of a hat?)
In the VW story, the test-bench vehicle was fundamentally different from the market vehicle, and the road version was designed to behave worse on the metrics to get other gains. I happen to know someone who bought a diesel Jetta specifically because it was more eco-friendly than other options, and I think he'd draw a clear line between tuning for test metrics and VW consciously lying to their buyers.
Having measured all my gadgets with a Kill a Watt meter, that's not my experience. It seems that many gadget-makers realize that people don't really care about power draw, so they just slap the maximum draw onto the specs.
The VW test is not like that. There's no way to innocently arrive in the scenario they did. They did not game a bad test, they literally lied to the test administrators. The car ran in "clean mode" only if it was in the test environment. If the car ran like it did on the road, they'd have failed (which is how they were caught, with a mobile testing setup).
One of the points in the article is that regulating for safety based on known testing conditions is going to result in over-fitting for the test. The water heater company is guilty of intentionally over-fitting. VW just straight up lied. I don't think those 2 actions are equal, VW is worse, but I agree that both are dishonest to a degree.
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.
What VW did was to take a clean-burning car and disable the pollution controls under normal driving conditions, for performance reasons. So while to the consumer it seems deceptive that VWs get better performance than they should, given how clean they’re supposed to be, in reality the cars are illegal and spewing toxins they were supposed to be removing from the exhaust. This makes the cars not only a pollution source but a health hazard to people living nearby.
To get on the same level of VW, the water heater would have to be doing something like emitting low levels of carbon monoxide into the home while having a feature that avoids doing that in the laboratory. In other words, reckless and willful disregard for human health and life.
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.
What placement of components would be ethical? Should engineers required to be separated from the test parameters by a Chinese wall? Do they need to build the system for the worst result? Some middle ground? If the engineers are unethical, where is the line?
The obvious answer to optimizations like this are for the testing body to tweak the test procedure based on what manufacturers do over time. That provides an incentive to be more conservative or accurate.
If the water heater manufacturer had special heating elements that only ran during the test, it would be equivalent.
I think this is what I disagree with.
The water heater story is about a viable-for-market design which also optimized for the test. The equivalent for a car emissions test might be optimizing the transmission to reduce emissions at the specific speeds which will be tested. Those speeds could be sweet spots of the engine curve by accident, or they could be planned that way. I don't think that's necessarily right, but it's within the bounds of "natural" design for the product.
Instead of doing that, VW submitted something for testing which was fundamentally different from what went to market. Rather than being misleading, the test results were fundamentally irrelevant. Creating two completely different modes of behavior isn't something you could do by chance, and it means there's no real limit on how badly they could cheat.
Rarely the purpose of tests is to assure the public of your fitness (e.g. a driving test) and cheating those might be a problem, but if you cheat my CS 101 course and then struggle because you needed remedial classes but the cheated test means you don't get them that's your problem.
> Sun managed to increase its score on 179.art (a sub-benchmark of specfp) by 12x with a compiler tweak that essentially re-wrote the benchmark kernel.
I agree that what Sun did is very similar to what VW did, with the exception that VW's increased emissions (statistically speaking) killed people, and what Sun did likely had no health impact on anybody except a few hurt paychecks.
The water heaters don't sound like they'd fail any given test.
Why are we not holding those doing the measurement accountable as well?
If you produce a test that can be gamed and your job is to test things to meet consumer expectations, you've failed at your job.
After all is said and done, what is a better outcome:
a) VW is punished for gaming the test
b) the test is significantly harder to game
With (a), we have only one less manufacturer gaming the tests, VW. With (b) we have tests that none of the manufacturers can game any longer or at least will take time to game. The testers should be expected to always be two steps ahead.
This is not unlike whitehat/blackhat security engineering. We should pay bug bounties to teams that successfully exploit the tests and we should be actively running red team drills.
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?
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.
It's your claim "the water at the level of the heating elements gets hotter and hotter and the water away from it gets cold" which is surprising me; water being quite a good conductor of heat, and "efficient boiler" suggesting that the tank will be insulated so not much heat is lost to the outside world, so the water away from the element should warm up by conduction from the other water faster than it gets cold from losing heat through the insulation (in my head). OK maybe I can imagine that in a fixed pressure with no room for expansion, the warm water cannot be less dense, so there can't be much convection - but then won't the heat radiate and conduct outwards in a "sphere" from the heating element including up and down, and not make any layers?
And here is a video of Thunderf00t putting an infra-red thermal camera on a closed water bottle with a peltier cooler attatched to the side of it, and showing that the cold water does sink, there is some convection happening with a cold "heating element" halfway up the "tank" on one side. (But there is compressible air in the top).
Maybe it's that you don't want to run a boiler long enough for all the water to get to a uniform temperature before you can get warm water out of it, and if you don't then you risk getting super hot and cold water unmixed from "impatience" more than anything else?
Suspicion of mine is part of the answer is that the viscosity of water drops with temperature. Rising hot water in a warm layer hits the cold layer above it and spreads out then turns down. Also water is a middle of the road non metallic solid when it comes to heat conduction. But it has high heat capacity and is a liquid.
Complicating things stratification at least in a well designed water heater happens rarely. So it's easy enough to set up conditions where it doesn't happen. But of course it's a known problem. And not a totally solved one either. Suspect that simplified models probably don't display the behavior.
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 in each direction?
What is most dangerous: crossroad with no traffic lights? Turns? City? Highways or smaller roads?
I was not able to find any meaningful research. There are ratings by different government agencies (US, UK, Australia etc), but basically all cars have highest rating which I find hard to believe.
A little nitpick: Motorcycling, cycling, and walking are all significantly worse than traveling by car.
If this interests you, it's possible to find a lot more interesting research by searching for "microlife" and "micromort".
Motorcycling, cycling, and walking are all significantly worse than traveling by car.
Here lays the body of William Jay,
Who died maintaining his right of way,
He was right, so right, as he sped along,
But he's just as dead as if he were wrong.
If you're talking about trips of no more than a few miles (that don't include hauling too much cargo to carry), you can compare driving with walking. If you're talking about trips of tens or hundreds or thousands of miles, you have to compare driving with flying or taking a train.
I would be interested to see crash/injury/fatality stats for car trips under certain distance thresholds. I wonder if those are tracked anywhere.
Of course, part of the reason these crashes were newsworthy is that they were unusual. Are there enough takeoff- and landing- related losses to make these statistically irrelevant?
I didn't count them all, but from eyeballing it a 1000-mile journey is 3x as likely to kill you as a 100-mile one, not 1x or 10x.
When a car and a human collide, it's not the driver that's likely to die.
I got my stats from https://en.wikipedia.org/wiki/Micromort which shows walking approx 12 times as dangerous per mile.
On a time basis walking would be less dangerous than driving I reckon. Walking also has other health benefits.
I mentioned it specifically, because walking to the store instead of driving for safety reasons would not be a smart choice. Doing some daily walking in a park likely would be a smart choice though.
Per se walking is definitely safer, given decent walking conditions. If all you got are sidewalk-less streets and only big shops that are a decent distance away, that's not the fault of walking but of bad city design. similarly in winter, if there's snow and your city clears the street but not the sidewalk then of course the sidewalk is less safe.
Consider a spherical traveler following a certain path in a field of randomly moving projectiles. The chances of being hit with one depends on path length, your own size, and how long you stay on the field.
Seriousness of the hit depends on your durability and speeds involved.
Maybe pedestrians just spend a lot of time exposed (assuming they have to cover similar distance) and bikers are extra fragile.
I think part of the dissonance is that intuitively I tend to compare on a time basis. I guess it depends on whether one is traveling to a destination (constant distance) or traveling for recreation (constant time).
Here in the Bay nobody stops at stop signs (3-10mph is typical), and they don't even really slow down to look both ways till after the white line and after the sign -- plowing straight into sidsewalks and bike lanes. I'm honestly shocked it doesn't cause more deaths.
Cyclists themselves usually aren't much better -- not even bothering to slow down for a 4-way stop, failing to signal before turning, etc....
As a personal anecdote, I was biking home down a pretty steep hill (I had lights, a helmet, etc) last fall on a road without any shoulder or bike lanes whatsoever. It was a short stretch, there were plenty of signs warning cars of cyclists, and I thought it would be fine, but shortly after I started the descent I had an SUV tailgate me the entire way down the mountain (again, nowhere for me to pull over, no way to get out of the way). If I'd hit a rock or anything and lost control I would've been toast.
When I checked my GPS after the fact I had been going a minimum of 10 over the limit, but that wasn't enough for somebody in a hurry and apparently not aware they were risking my life.
Commuters over several years who cycled, were 44% more likely to be hospitalised than other commuters.
However...! This cycling was associated with some quite dramatic health benefits. If 1000 people switched to cycling... The benefit would be 15 fewer cancers, four fewer heart attacks or stroke and three fewer deaths.
The news, social media, etc should be plastered with the 100+ people who needlessly die every day in car accidents. ALERT: 10 YEAR OLD CHILD SLAIN SO DRIVER COULD GET TO WORK 30 SECONDS EARLIER
(Side note: This is why I'm going long on the stock market again.. it looks like the public and the media have gotten over being scared of the virus. Even if we have another 100-200k deaths in the USA this year, my guess is it'll get swept under the rug just like 50k car deaths, regular flu deaths, heart attacks, etc)
Being inside a big metal shell that can’t fall over and with active safety measures is a great place to be, risk-wise.
In fact, once you take into account severity, the GP's claim seems extremely suspect: maybe the chance of any injury on a bike or by foot is higher, but I'd be skeptical of claims that the same applies to death, or even chance of serious injury (since that's what I, personally, care about), without serious backing evidence.
They're also somewhat difficult to compare at a nationwide level because driving in the suburbs is not really comparable to biking in the city, in part because the miles per trip in suburban and rural areas are so great that biking and walking aren't really feasible, anyway. This poses a big selection bias problem: What if the real underlying effect is that suburban transportation is generally safer per mile, perhaps even independently (as much as they can be separated) of transportation mode? For that matter, are we even measuring the right thing? What if the metric that really matters is deaths per passenger-hour, or deaths per passenger-thing-you-need-to-get-done?
City driving and city biking or city walking, on the other hand, can be much more comparable. For example, I own a car, but typically use a bike to buy groceries. In part because, where I live, it's the quicker and easier option. Similar story for driving vs. walking to go to my favorite restaurant, or to go to the hardware store.
Finally, I think we'd be remiss not to think about how it's being framed: The original data focus on likelihood of being the victim of an accident. It's maybe more properly called "deaths experienced per passenger mile." The numbers would look entirely different if they were framed as "deaths caused per passenger-mile." That's kind of a big deal, because one framing suggests, on an instinctual level, that cars generally increase public safety, while the other, I'm guessing, would suggest that cars generally reduce public safety. It's the difference between saying that Elaine Herzberg died because she was walking across the street, and saying that she died because an Uber self-driving car hit her.
When was the last time you saw a bus get north of 60mph? Exactly.
And for crashes with other vehicles their mass makes them pretty safe for occupants (in the places buses tend to roam it's hard to find enough space to get a small car up to the speeds necessary to hurt the occupants)
If it was for safety or because he hated lefties is not clear.
Citation please. This is the first time I've ever heard him called that. There was some speculation he was gay but nothing conclusive AFAIK. In any case he's one of the last people anyone should pick as a positive representation of their group.
I was just trying to be witty when telling a story. Not make any grand statement about anything.
However my gender remains resolutely unaffected and I have no time for people who expect otherwise. Judge a book by a cover you might, but slipping the dust jacket from Moby Dick onto a copy of The Princess Bride certainly won't make it into a story about whaling.
Also, this word always reminds me of Eddie Izzard: "They're not women's clothes, they're my clothes, I bought them".
Similarly, I estimate ~2 deaths per million cigarettes smoked (~1000 cigarettes/year/person >= age 15, 480k deaths/year), and while driving a hundred miles in a day is unremarkable, smoking 100 cigarettes in a day is pretty astonishing, but I wouldn't say that cigarettes are not that risky. The total deaths per capita are high.
(To be clear: cigarettes are more dangerous than driving any way you measure it. I'm just showing that you get to weird places if you look at risk/unit, without looking at total volume).
If 1 women can produce a baby in 9 months, then 9 women can produce a baby in 1 month.
And a further 16% of those deaths were related to the use of other drugs such as marijuana.
And those are just the drugs/alcohol related deaths related to driving.
death rates per million hours of activity
It must be "fatalities from X during Y", and that makes sense when X and Y are the same thing (e.g. sky diving), but it seems like X and Y diverge in some of these entries.
Whereas other activities that may have similar risk profiles for typical "active participants" may have much different rates relative to the time spent actively participating in the activity.
There's no single metric that really represents a correct view.
- Fishing seems to be quite dangerous!!??
- Swimming is less dangerous than living (all other causes)!
Airline pilots have sometimes been caught, most flights just aren't long enough for you to be sober at both ends yet drunk during the flight - but for the crew of a tramp freighter so long as they sleep it off before they come into port nobody will know - unless there's an accident and suddenly everything is happening with unseemly haste.
Rocks are slippery.
Note that this says nothing about how many actually die from X. And what is the Nth leading cause, depends entirely on how you classify causes.
The leading cause of death could be 80% of deaths or 4%. But most people will read probably the phrase as "more than half of deaths".
Little things. Motorcyclists in white helmets get hit slightly less, so I wear a white helmet. 50% of Motorcycle fatalities involved dwi level BACs, so I obviously don't drink, but then another 40%ish of the remainder involve any amount of alcohol at all, so I simply don't get on the bike if I've even one drink in the past several hours.
Rain adds risk, night adds risk. Choose one and I'll ride. Both, no.
Majority of accidents happen at intersections, so every single green light has me slowing to look both ways. I watch behind me at reds. I don't get in the middle of intersections to make a left turn, I wait in the turning lane.
The first person I bought a bike from gave me fantastic advice: if you have to think about it for a second, just don't do it. Thinking about that narrow pass on the freeway? Let it go, you can pass in a couple seconds after the gap widens. Thinking about gunning through the yellow? Relax. Just stop. Etc.
I can't speak for cars but so many things are measured for motorcycles. Where our heads hit the ground, what our gear does for us, where we crash. There's also tons of videos from GoPro mounts of many kinds of crashes we get into. Over time you can build a sort of risk management software inside your brain I think.
That totally applies to driving a car as well!
That also applies to driving.
edit: Unintentional. I meant, it's not those situations where I think for a second and make a bad call - it's those situations where I act without thinking at all.
What you've said basically is to convince motorcyclists that they're 200% responsible for their own safety. Unlike cars, you just can't trust in the horde.
Which makes riding in places like Vietnam all the more interesting - the horde of 2 wheeled vehicles flows like water. The more you think about it, the more you fail to mesh with it. Better to flow with the rest of them. Very interesting place.
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 buying an expensive, depreciating asset. Sure, maybe your housing cost is higher in a city like this - but your house doesn't lose value like a car.
It's also more pleasant to live in. I love the rural areas, and I love the cities, but the suburbs are just the worst of both worlds.
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.
So long as that is the requirement it won't be done, nobody will do it. You need to find a different starting place.
Start by not requiring buildings be far apart and have parking. Right not the neighborhood you envision isn't legal to build if you want to. Make it legal.
Make tax codes encourage building high. Charge higher taxes for the ground floor.
Allow everyone to build by right (meaning no public hearings, permits must be approved by buerocrats) up to the road/sidewalk or property line.
Even if the building is setback from the property line require the outside walls be built to up the lot line on all sides standards. That means fireproof if the building next door burns. That means can be demolished without anything falling to the outside, or even a need to do anything outside to demolish it.
For bonus points define places where a door to the next building must be located. (you might never visit your neighbors that way but the door still exists and can be repurposed to a public walkway when you leave and the new owner has other ideas.
If you have a larger family and a limited budget, suburbs are the best of both worlds.
Also cars are quite reasonable unless you want new ones before their useful life is exhausted. A modern car will usually last 25+ years, which is more than many homes before they need major renovation (new roof, windows, etc. in the US).
Exactly. Nissan and FCA will finance anyone with a pulse and they make cars at low price points. The Juke is just about the cheapest AWD crossover so you get a statistically unflattering clientele driving it. You can see the reverse situation with the Dodge Journey. It is known for being the cheapest people hauler on a per-seat basis and also has a very unflattering set of customers. The 2wd is statistically more dangerous than the 4wd presumably because the riskiest buyers don't care how many driven wheels it has they just need something with a lot of seats for cheap to haul around their massive family.
It's still a really nice feature that has its uses, but most people I talk to about it (admittedly a small subset of people who use AWD) greatly overestimate its safety benefits.
Everyone(TM) prefers AWD for it's superior go-ing abilities even if the turning and stopping abilities are unchanged. An obnoxious vocal minority tells them they're wrong. Since it's a matter of performance and consensus the overwhelming majority can't be wrong though.
I have a fleet of several identical station wagons. There is one of them that's FWD. They all use the same brand of tires. It's as close to scientific experiment as you can get. The FWD one sucks in the wet/snow/anything but dry. Forcing all the horsepower to go through just two tires that also have to do double duty and steer the vehicle make it peel-out city. The AWD ones are much more tame. But the FWD one gets a couple more mpg so we keep it around. Given the choice between snow tires on the FWD wagon and driving one of the AWD wagons on all season tires I will pick the AWD one every time. Having a marginally shorter minimum stopping distance and being able to corner better is less of an improvement than having a substantially reduced likelihood of peeling out on an uphill.
The above opinion is shared by the other four people who have to drive the vehicles in question which is why I'm the one who gets stuck driving the FWD one when it snows.
Note that your statement could be taken as either confirmation or refutation of the OP's point, entirely depending upon whether the reader believes you're an unreliable narrator. Not knowing you nor having driven an AWD car, I'm not qualified to guess which is true. But as someone who's super interested in the distinction between reality and perceptions of reality, I thought the juxtaposition was pretty intriguing.
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.
I would see way more SUVs in ditches than sedans. People tend to overestimate what their 4wd is going to do for them and aren't sufficiently cautious. The first snow/ice of the year was particularly bad.
Or because when it snows the ones who can afford to do so take the "winter beater" 2002 Trailblazer instead of the car they usually drive.
4x4 drivers might do offroading: so the figures could be much lower than if those people had 4x2 (2wd) vehicles.
That being said, I see obvious self-selection issues show up in that chart all the time. Looking at the extremes usually points it out -- 'old man' sports cars usually have very low accident rates. Vehicles sold with deep discounts or aggressive financing deals usually have high accident rates. These are likely bought by very different buyers with very different life circumstances who use their cars very differently.
Driving while impaired in some way certainly is more dangerous. (Drugs and alcohol but also just fatigue.) Driving too fast for conditions. Bad weather, especially snow. I'd say in general that highway driving was probably safer than secondary roads--again assuming not excess speed.
One of the things I like about greater work flexibility these days is that I rarely have to drive in snow. I just stay home.
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"
The usual counter-argument is that the use of the word "accident" is a statement of intent, and outside of extreme road rage scenarios, nobody intends to cause a crash. However, the creation of an unsafe situation, such as texting while driving, is often absolutely deliberate.
Didn't check your blind spot before making a lane change? That's not an accident, that's negligence.
TBH, I'm not even sure if any crashes could really qualify as an "accident".
Humans are fallible and make unintentional mistakes. It's surprising that humans are as good at driving as we are and that most of us aren't making catastrophic mistakes on a regular basis.
Less than that. There have been many studies done about the efficacy of vehicle "safety" inspections on making roads safer and they range from "no effect" to "positive effect about as big as the noise threshold". There was some Danish meta-study I thought I had bookmarked but can't seem to find that spells it all out.
That said, I 200% disagree with the overall opinion of your comment. Typical human behavior is not negligence. Systems should take into account normal, error making, humans and not expect perfect "behave like a computer humans". Behaving normally, even if that means not checking your blind spot as well as you should 1/100 times is not negligence. Furthermore there's only so much situational awareness a person with two eyes facing the same way can have. As another commenter points out you're gonna be in for a near miss at best if the time you're checking your blind spot is the same time traffic in front of you starts coming to an emergency stop.
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.)
Oh and SUVs are markedly LESS safe. They are more prone to rollover, less likely to avoid an accident, stop slower, and generally have less safe body structure.
But they're also heavier, and there exist cheap, heavy SUVs, while cheap cars are generally lighter.
Dress like a motor-cyclist. Wear a helmet and airbag suit.
This is probably also useful when traveling by airplane.
I have no data on the effectiveness, however.
Interesting, I'd certainly say it applies to me - I dive more in volleyball if I have my kneepads; I tackle harder in football when wearing shin-guards, the moreso with ankle protection; drive far more cautiously on a motorbike than in the metal, crumpled-zoned protection of a car; etc. ...
That tweet leads to https://www.sciencedirect.com/science/article/pii/S136984781... "Bicycle helmets and risky behaviour: A systematic review" which concludes:
>"Although two out of the 23 studies were supportive of risk compensation, ten other studies found helmet wearing was associated with safer cycling behaviour." //
So, risk averse people wear helmets.
Some of the support in the review comes from results like helmet wearers obeying traffic laws: the issue seems much more nuanced and complicated than that.
FWIW, risk compensation doesn't require that the entire risk is negated (or even over-compensated) so statistics on accident occurrence and severity alone - for example - would not be sufficient to prove if the effect is real: take my car driving, no matter how much I exhibit riskier driving in a car - short of being a lunatic - it's not going to make it more dangerous than motorbike riding because of all the other people on the road.
[This post relies on part on past activities and experiences!]
Hey this may be an unpopular choice, but it is the one with the biggest safety impact! And that was the question.
Vehicles and Crashes: Why is this Moral Issue Overlooked? by Douglas Husak
People are starting to wake up to the notion of "systemic issues," but still too slow to apply what they've learned about that topic to other matters. It's a mistake to focus on the behavior of individuals in a system that's sanctioning and encouraging bad behavior.
Safety equipment inside cars does the same -- people who feel more safe in their car drive more dangerously and take more risks. Maybe that's addressed in the full article.
So I'm not sure "big car safe" is necessarily true.
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)
If you crash into a wall at 20km/hr, it's a lot better if the engine bay gets smashed up, than if the compartment you're in collapses around you.
"No fatalities ever recorded in a Volvo XC90 in the UK
- Analysis of official figures finds no driver or passenger fatalities have been recorded in Volvo's XC90 since records began in 2004"
Volvo XC90 is a relatively popular SUV there, and for the UK, quite large.
"Around 70,000 XC90s have been sold in the UK since the original model launched in 2002"
I would guess the magic here is:
a) the car is designed with safety as the number 1 design criterium (it's a Volvo)
b) it's quite large (lots of crumple zone mass)
c) it's probably not driven at insanely high speeds by young male drivers with poor impulse control very often.
Start including the effect on other cars in crash tests.
In other words, yeah, if I drove a frickin' monster truck, yes, it's going to be extremely safe for me, but it's absolutely deadly to anybody in a sedan. So that monster truck should get low crash test scores.
Your answer merely creates an arms race of larger and heavier cars.
So if you really want to reign supreme on the road you ought to get a semi truck, with a sleep cab you convert it to seating for the kids too.
Is this the end game of suburban families race to owning the biggest hunks of steel on the road?
Pluuus, Larger vehicles suffer from worse handling, worse braking distances and higher accident rates. It's all just dumb.
Its the "truth" until you run into something that's bigger than you.
It's a shame. The pedestrians will have to find a way to get taller too.
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.
When you all have big cars, you're back in an equilibrium where everyone seems as safe in head-on collisions as the equilibrium where everyone drove small cars. But each car now has way more kinetic energy and momentum, and needs bigger crumple zones to absorb it (oops! You won't find room to expand those in side collisions!), is more prone to rollover, has less visibility of pedestrians, bicycles, and children playing in your driveway, worse gas mileage, more pollution, less parking space, etc.
And then someone decides to get an edge over the crowd by driving a monster truck and you're back to scrambling into a new, even worse equilibrium.
All the pedestrians and cyclists they mow down are less safe though.
And everything becomes more polluted, which is presumably also not equally safe.
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 degree?
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.
Well it's zero sum in the linear sense as the relative total velocity change is the same, but crash survivability isn't linear. Rather, it decreases exponentially, since kinetic energy is proportional to the square of velocity - so a head-on crash between a semi and a compact car subjects the occupants of the compact car to nearly 4x the force that they'd be subjected to if they crashed into another compact car.
However, please read what I wrote here:
I guess what I was looking for was actual data, not assumptions.