"That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!"
Americans drive an aggregate of 3 trillion miles every year, while Tesla drivers have done 100 million (and they don't cite this number; are they including test drives?). That's well over an order of magnitude difference. Plus, the average Tesla driver is currently probably a superior driver (if for no other reason than they have a brand new expensive car) and has taken better care of their car (since it's within 2-3 years old, tops). In theory, Teslas will eventually become more mainstream over the years -- resold, price drops, lower-end models, etc.
Again, I don't think their conclusion about Teslas being safer overall is wrong. However, their conclusion of the likelihood of a Tesla catching on fire seems off, and the exclamation mark makes this press release seem glib.
I can play the conjecture game too.
The average Tesla driver is probably a worse driver than the average gas-powered car driver. Why? Because they have the disposable income to purchase a Tesla, which means they're probably less careful with their possessions (as they can presumably afford to replace them), plus the Model S is a sports car so they're probably driving faster and more carefree than your average person.
Not that I really believe this, but come on, your argument is completely made up.
Musk is speaking definitively, and has literally a billion dollars at stake with this post.
My point wasn't necessarily that I'm right -- much like you, I'm just arguing that the logic isn't as simple as it's made out to be.
So if I drove that 100 mile/workday commute for 4,000 years, something like this might happen approximately once.
Incidentally, I have seen, during said commute, the remains of an ordinary car that caught on fire. There was nothing left but a burnt skeleton of a car that appeared to be made of ashes. I'd rather be in the Tesla while it was still on fire than the burnt wreck I saw.
But risks must be compared to the relevant alternatives. Certainly, those who arrange their life such that they do not drive at all are removing a significant risk, as I can personally attest to having encountered several drivers who were, frankly, suicidal. I speak specifically of the person who pulled into a turning lane to pass (when I was already in it, stopped), and gunned it driving straight at me. By no means should you think that I am diminishing the very real risk we engage in every day while driving.
But most people measure risk by how easily they can imagine a scenario. As such, I offer this for you to contrast with the photos in the article: https://www.google.com/search?q=burnt+out+car&tbm=isch Such things are not uncommon and I have, personally, witnessed such. While measuring risk according to one's memory is a useful cognitive shortcut in many situations, but with the way our news sensationalizes things by highlighting unusual events and under-reporting common ones, it is not a useful metric.
Just like Elon did it, it sounds nice but doesnt make a lot of sense.
Note that there have been a lot of fires in those 3 trillion miles driven by ordinary cars (not just 1), as even a quick search shows: https://www.google.com/search?q=burnt+out+car&tbm=isch
On an individual level, I am far more worried about identifying and avoiding the disturbingly large number of idiotically suicidal drivers I have met. And I mean that very seriously: as soon as I identify someone driving erratically, I find some way to get away from them, whether it means forcing them to pass me, taking an unplanned exit, or what have you, I will make sure I put distance between us.
But I remain unconcerned about a single report of a small car fire when there are many worse ones every single year (if not every day...)
I do use the Prius in the city though, I easily get 75+ mpg when supermiling.
I love my 1 year old Son. That makes me more terrified to drop him.
Do not assume just because someone is able to get enough money to buy something expensive,that they have tons of money. By that same logic, anyone who is able to buy a home is clearly flush with cash and able to throw it all around. Completely ridiculous.
As for the house argument, you and I both know that the two are totally incomparable. Putting a roof on your head is a much bigger priority than buying an electric supercar. People need to pay for shelter. They generally can't afford to pay a lot for luxury cars. If you argument is true, why isn't everyone buying $63,000 cars? (Not to mention the millions of people who can't even afford homes.)
Your posts demonstrates everything that is wrong with class stratification in America. I don't think you or your friends who elected to choose Teslas over Porches know what it means to be "average."
That means this SF bay area laborer must give up a Saturday or Sunday afternoon every week, but it's hardly impossible "to afford" or a "massive tradeoff in quality of life." On the other hand, it's challenging to haul a few thousand pounds of mulch in a Tesla, I expect.
Oh, and the $600/mo assumes a $7100 down payment, which needless to say is far more than the average down payment on a car and is really more like what the average american puts down on a HOUSE. In other words: c'mon.
Not to mention the opportunity cost of that money. If you're making $25/hr in SF you do not have a high standard of living, especially when compared to your neighbors which, studies have shown, is exactly how we measure our own financial happiness.
Though you're right about the down payment, so let's assume it will be a used Tesla and therefore cheaper. And you're right about the relative comparison point. But these were rough numbers, remember, and not intended to be a detailed argument as much as a refutation of the impossible "to afford" claim above.
I'm really confused by "average, middleish class people who normally would have bought a porsche or a tesla" - is that a typo? Did you mean "would not normally"? If not, your idea of "average middleish class people" is really oddly out of whack.
Many people by homes because of a calculation that owning a home is cheaper in the long run than paying rent over that same period of time. Many people buy homes not based on such a calculation and simply because they have disposable income and owning a home is nice. Many people also buy homes based on neither financial decision-making nor disposable income, and I seem to recall this having some negative impacts on our economy a few years back, which may make it a poor analogy to why it makes sense to buy a Tesla (or a porsche?!) without disposable income.
Then go look up the real numbers.
I suspect you're in for a surprise.
You're either being disingenuous or your perception of reality and normality is really skewed.
You'll probably see the posts saying this to you as condescending, but if you can even think of purchasing a Model S you're in a very exclusive group of people.
When one tiny sliver of society (web engineers) simultaneously wields so much influence (as web companies do) and is so cut off from the reality of America (as you apparently are), it doesn't bode well.
Outside of a couple critical mass areas in the US -- I'm thinking SV, greater Boston, NYC (just because everyone there is in their own little bubble ;) ) -- it's just another job.
And if you're not in the US, I wouldn't even know where this sort of SV halo exists.
I grew up in a ~30k household in the 90's. Something I would call lower middle class. Upper middle class is probably ~70k-100k.
$100k does not go very far in San Francisco and Manhattan. Nobody making $100k in those places could reasonably afford a Tesla without severe over-spending (which they're welcome to do if they want to--whatever floats your boat). If you view the middle class as owning detached single family homes with yards, you would be lower middle class at best in those cities at $100k. If your spouse also made $100k, you could afford the crappiest single family home that was still livable.
But it's a really good salary in Denver or Houston; you could definitely find a nice house to buy and afford comfortably, though it might have a bit of a commute. If your spouse also made $100k, you could afford a nice home in any neighborhood with no commute.
And it might nearly qualify you as wealthy in a small rural town of 15k people total, where you would never need to spend more than $150k on any house.
You know what else? Travel. Domestic and international travel is a LOT more affordable when you're making $100k in SF.
And a big one: Retirement. You sock away your SF salary for 40 years and then retire in a cheaper COL area with no state income tax.
The truth is, even here, $100k is a lot of money. It really is. It's not rich by any stretch, but it's certainly not average middle class living. It is frustrating that a couple making over $200k can hardly buy 1000sq ft house while staying inside 30% (of gross income) housing budget, a metric widely seen as "affordable housing." But still, on balance, that couple making $200k is doing very, very well.
And the truth is, there are a lot of engineers here that, with liquidity events (which might just mean vesting your RSU's in an already public company), are earning $200k a year. That literally puts you in the top 1% of wage earners. (But not in THE "1%" of course which is usually a term referring to net worth and not gross income. But still.)
The math is different of course if/when you add children to the mix. But I deliberately left them out, because in reality, it's just not a common lifestyle choice in San Francisco.
And, yes, of course I'm aware that a Model S is the same price no matter where you buy it, to a first approximation. The point is that housing is so expensive in the Bay Area that you can actually end up having less disposable income left over for your car than someone making $20k less than you on paper in a much cheaper city and in a state with lower (or no) income taxes (Washington, Texas, maybe a few others?). If you don't believe me, you need to just sit down with a calculator that will do taxes and everything, look up comparable rents, and do the math. You sound like you might be surprised.
Small correction -- state income tax in CA is a big deal even if you're saving for retirement. And once you retire, you presumably won't care what the state income tax is.
Retirement savings goes into tax advantaged accounts like 401ks and iras. This is pre tax income. You pay the taxes at the end, when you're drawing from your accounts during retirement.
But for those people, taxes are immediate rather than deferred.
Actually, Roth IRAs are limited to $5000 a year per person, and once your income reaches ~$110k you can't deposit into a Roth at all. The vast majority of private retirement dollars are saved in 401k accounts that have have a cap much higher than in a Roth. Three times higher.
And actually, if you do the math (or just go read the math) you'll see that there is very little difference in your total retirement funds whether you use a pre-tax or post-tax account. This is because in a pre tax account you have the advantage of earning capital gains on the IRS's dime. The wisest choice is of course to use both if you can. Though many many people living in this area, due to income restrictions, cannot.
Anyway, I intended my reply to you as just honestly informative. I'm happy that you now are informed, but there was no reason to say "uhh, i mean a roth. yeah. a roth."
My reply was in the context of the $100k earner mentioned earlier, who would not be restricted from contributing to a Roth. Our hypothetical young tech worker is going to expect his or her real salary (and tax rate) to go nowhere but up as the years roll on. It's not bizarre to imagine this person might choose Roth rather than traditional for individual savings, independent of any 401k they might be contributing to.
There is only one way to read your comment:
"Small correction -- state income tax in CA is a big deal even if you're saving for retirement. And once you retire, you presumably won't care what the state income tax is."
You didn't qualify that! You added a "small correction" that was anything but. And yes, you got me, I didn't realize that for 2013 (possibly 2012?) the Roth limit was increased to $5500. Still not much stacked against the $24,000 I saved in my tax deferred accounts last year.
Listen man, i'm not one for silly debates on the internet, so go ahead and have the last word. But If you're going to add a "small correction" that is not really a correction, you should expect some disagreement.
Perhaps what you really meant was "That's true, unless you chose a Roth IRA as your only form of retirement savings. In that case, current tax rates matter and future tax rates don't."
That still glosses over the fact that I'm talking generally and you're talking about a specific, somewhat rare scenario. But at least it's accurate. As it was, had I not replied to you, a casual reader would've read my post, then yours, and walked away assuming that retirement savings is taxed at your current tax rate, in your current state of residence, when in reality it's just not so.
Consumer goods like cars and laptops and TVs will cost the same, to a first approximation, anywhere in the continental U.S. But in some coastal areas, you have real estate costs that are 20x that of cheaper areas with salaries/compensation packages that are generally not 20x higher. In central Pennsylvania towns the median household income, for instance, tends to be around $26K and the median house cost is $64K, meaning houses are 2.5X median income.
In Palo Alto, on the other hand, the median house cost is around $2.25M, and the median family income is around $160K, meaning houses are 13.75X median income. Part of this are older PA families who bought when land was cheap many decades ago and are grandfathered in with lower tax rates, but part of this is also people who are stretching their finances dangerously to be able to afford there. (Even though those $2.25M median homes are often smaller than the national average, measured by square footage.)
It's possible to make $100K in the SF bay area and be, in real terms, poorer than someone making half that in central Pennsylvania.
Population of San Francisco: 0.8 Million.
Population of Manhattan: 1.6 Million.
Population of London: 8.1 million.
Percentage of the world's population living in either San Francisco, Manhattan or London: ~0.0015%
Exactly what do you think an outlier is? If you live in one of those three urban areas, you're already a member of an elite class.
But I don't really understand why living in an expensive urban area automatically puts one in an elite class. The standard of living is not much better than other places for one thing--what you gain in diversity is lost in housing conditions. Also, it's not like $100k wages there are super rare. You don't need to be a 4.0 Ivy League graduate to score a livable wage in San Francisco. That's the starting salary for a lot of professions in cities like that, not just software developers. Police officers in the SFPD can make as much as a Twitter engineer fresh out of Stanford: http://www.sf-police.org/index.aspx?page=1655
Edit: I can't edit my prior comment. Time window?
I'm not crazy about percent notation. I find it confusing. I might have written it thusly:
> 0.0015 of Earth's population are living in San Francisco, Manhattan or London
I wouldn't buy a Tesla on $100k in North Dakota either. Maybe, if I felt like blowing through money, I'd get a BMW 3 series or Audi A4, both of which are still considerably cheaper than a Model S.
I was just pointing out that besides housing (especially owning) the cost of almost everything in CA is the same if you move somewhere where the cost of living is lower yet the salaries elsewhere are significantly less. So there is an opportunity to save a lot of money if you are willing to compromise somewhat on your living conditions.
I suppose it depends on whether you think it's important to own your home and/or you mind having roommates. When I first moved to CA I had severe sticker shock re: the rents so I rented a room in nice houses with other young professionals for the first 5 or so years I lived here.
If you can afford to spend the average household's entire annual income on a car coolness upgrade, then yes, you have disposable income to throw around, and no, you're not middle class.
Or sense. Or street smarts. That was the OP's point.
That said, I'm not really sure why this is such big news. Accident happened due to debris on the road. No one was hurt. The car was severely damaged, but got the owner to safety.
AND THEN a small fire happened...
Then I read things like this: http://www.dailynews.com/general-news/20130928/5-killed-1-in...
Let's consider this for a second - Tesla Model S had a no-injury accident and made national news. 5 kids burned alive in a Sentra, and this barely stayed on local news for 3 days.
Tesla Model S is a phenomenal vehicle with an excellent, if short-ish, track record. It really annoys me that reporters go out of their way for sensationalist articles, when there are far worse tragedies to cover.
What does that mean? Taking a common definition of "marketing" to be "expressing the value of a product to potential customers," any article that is about safety or about a recent product incident is also marketing. It sounds like you're using "marketing" as an ill-defined term that basically just means "something bad about the way a company publishes information."
This is not a dry facts page, but a public relations communication that is intended to sell you on the fact that Tesla Model S is a safe vehicle. Nothing wrong with that and nothing "bad" as you seemed to imply.
"The nationwide driving statistics make this very clear: there are 150,000 car fires per year according to the National Fire Protection Association, and Americans drive about 3 trillion miles per year according to the Department of Transportation. That equates to 1 vehicle fire for every 20 million miles driven, compared to 1 fire in over 100 million miles for Tesla. This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!"
* 150,000 car fires per year according to the National Fire Protection Association.
* Americans drive about 3 trillion miles per year according to the Department of Transportation.
* 1 fire in over 100 million miles for Tesla.
Sales pitch at the end: "This means you are 5 times more likely to experience a fire in a conventional gasoline car than a Tesla!".
The reason I call this a sales pitch or a marketing messaging, is that while the facts technically support this, as pointed out earlier, it's based on a data set of 1 occurrence.
Personally, I buy Musk's argument and if I was in the market for a new car, figuring out how to pay for Tesla would actually be at the top of the list for me. This story only re-enforces my own personal opinion that these are great cars.
Particularly for people such as Musk, who are doing so much to advance the expectations of consumers and raise the bar for what is possible with new technology (and here I'm speaking as an un-abashed Musk supporter), I can't help but support his rigorous defense of his projects. Whether it's the NYT "review" that attempted to slam the Model S mile range or the astonishingly good crash ratings for the same car, I think it serves us all to let Musk use his soapbox to be an advocate for his work at Tesla, SpaceX, etc.
The data on 100 million is probably enough to compare with the 3 trillion miles. The populations don't need to be equal to compare them, just big enough that they are random and distributed enough.
However, there was one fire over 100 million miles. The problem isn't the 100 million, it's the 1 fire. This wasn't a controlled experiment, either -- they just stopped the clock as soon as the first fire happened, and multiplied. A week ago, they could have said "You have exactly a 0% chance of your Tesla catching on fire" and have been right by this logic.
To think of it another way -- let's say you get lucky and get a hole-in-one your 10th time golfing. Does that mean you'll have 10 hole-in-ones if you golf 100 times? Doubtful.
EDIT: Also, don't forget that Elon is mixing numbers. There's no fire if someone doesn't run over something. All these numbers show is that the average driver is more likely to run over something. Of course Tesla drivers run over fewer things -- there are no 16 year old kids texting while driving a Tesla... yet.
For the purpose of our simple modeling, suppose that there is a constant risk per mile of the car catching fire, making an exponential model reasonable. Under this model, observing the first fire at 100 million miles would give a 95% confidence bound on the rate of fires of about one fire every 33 million miles.
If we're comfortable with the stated rate of about one fire every 20 million miles for other cars, then this would give a 95% confidence upper bound on the Tesla's rate of fires at about 60% of a normal car's rate. This isn't the 20% that Elon's statement would imply, but it does suggest a difference (which could just be due to other problems with the comparison).
That said, I also think the 1 fire is the problem here. Just think about how that relation changes with 2 fires.
If I had the cash I would still purchase a Tesla after the second fire as well.
But since the number of cars is increasing, it's not a Poisson distribution; if the chance per car per time is constant, you'd expect the time to the next fire to be shorter.
The median car in the US is ~11.6 years old, while Tesla's oldest vehicles were released in 2008, and the vast majority of their fleet was sold in the last couple years.
Obviously, the massive differences between electric powered cars and internal combustions engines means that they may never reach parity, but unless Musk has figured out a way to beat entropy, its pretty safe to assume that older cars will break down/suffer leaks/explode more than newer ones.
Please don't argue against statistics (mathematical information based on fact) when you don't understand them.
The Law of Large Numbers states that as more miles are traveled, the fires per mile will approach the expected value. It is entirely possible to have 10 fires in the next week.
We won't know what the expected fires/mile is until a much larger sample is collected. It will take years to prove out.
Here's a question (for anyone in this thread arguing statistics) that has an actual numerical answer: given the information in the article, what is the probability that Tesla's indeed experience less fires per mile than other cars? If someone doesn't know how to calculate the answer to that question, he shouldn't be arguing here.
This seems a bit dodgy since I'm "designing the experiment" after the fact, but I'm not sure how to correct for that. Any Bayesian experts?
You need an exhauseted state space. You cannot empirically infer a legitimate probabliliy, eg n/100m miles) with only a single failure observation, if there are 100 possible ways to fail. At best you have data on (1) of (N) ways to fail, but surely in the case of car accidents N=large.
A total of 2,650 cars were delivered to retail customers in North America during 2012, 4,900 during the first quarter of 2013, and 5,150 during the second quarter of 2013
Assuming 13000 cars on the road, each car would have logged 9k miles to get 110m road miles, as quoted by Tesla. But we know from past industry experience, that road fires are proportionate also with fleet age.
So, if anything we the probability of a road fire is likely to go up as more failure modes are discovered (including by chance), and as the vehicles cycle through a normal working life.
Our data is the fact that we went 100 million miles before a fire, after which exactly one fire happened, so we want to find the distribution `P(a|t = 100 million)` which tell us everything we want to know about `a`.
Then use Bayes' theorem: `P(a|t) = P(t|a) P(a) / P(t) = aw exp(-a(t+w)) / P(t)`. The normalization factor `P(t)` involves an integral over `P(t|a) P(a) da` from 0 to ∞, which wolfram alpha tells me evaluates as w / (t+w)^2.
So our posterior probability is `P(a|t) = a (w+t)^2 exp(-a(t+w))`, but we can take the limit `w -> 0` at this point for a fully uninformative prior: `P(a|t) = a t^2 exp(-at)`.
So we can just set `t=100e6 miles`, and now calculate things like the expectation of the distribution: `E[a] = 2/t = 2e-8 per mile`. Or the probability that the hazard rate is less than other cars, which is the integral from 0 to 1/(20 million miles): `P(a < b) = 1 - exp(-bt) (bt + 1) = 0.96`.
This wasn't after driving 100 miles. Aren't you off by 6 orders of magnitude?
By all accounts it comes down to the old bayesian/frequentist battle lines.
Of course, I'm exaggerating in the other direction. What we really should be calculating is the odds that Teslas burst into flames less often than the average car, given that the average car does so every 20 million miles and the first such event in a Tesla was at the 100 million-mile mark. We're still failing to account for the fact that the average Tesla is newer and probably better-kept than the average car, but it would at least be a reasonable start.
I don't know enough statistics to perform this calculation, but I would like to see how it is done.
For an exaggerated example, if Tesla had driven a billion miles and had 0 fires, you shouldn't say that there's not enough data - you definitely would have enough data to say that the chance of fire is below the gas-car rate of 5 fires per 100 million miles.
I'm honestly curious how one models this type of thing statistically, and I am not convinced enough of its obviousness to just accept numbers that someone throws around.
Polling 10,000 Americans would be vast overkill, in any case.
You can sample less than 2000 people and get 99% accuracy with a 3% margin of error for a population of 325 million. Increasing the sample size to 10k simply reduces the margin of error to 1.29%, hardly worth the extra sampling of 8k people.
Which is not true here, as the GP correctly notes.
 Assuming that you're not measuring average age or measuring 'who is at home', but if you want to see, say, the average political opinion of total USA population, which tends to correlate with age.
Furthermore, how do you gather the data needed to correct the polling numbers without being able to accurately poll people in the first place? Seems like a complete chicken-and-egg problem.
Of course, the refrain I often hear is that as long as you pick the RIGHT 1,000 Americans, it's as good as polling all 319 million.
If it's a proper random sample, then it's far better than sampling all 319 million because it's 95% accurate with about a 3% margin of error and vastly cheaper and actually practical; you can't poll 319 million people.
If you read the reports from the National Fire Protection Association they do estimate the number of "highway vehicle fires" at around 150 000 per year , but they also explicitly say that 'the term “highway vehicle fires” is used to describe the type of vehicle, not the location of the fire' .
If you look at fires caused by collision or overturn (which I guess this would be classified as) that's only 4% of the total, or 6000 per year.
Yes, this fire was caused by a collision, but fires caused by other things are relevant. If a Tesla car caught fire in somebody's driveway, people would be concerned about that too, right? So comparing 150,000 highway vehicle fires to 1 Tesla fire, regardless of cause, is pretty reasonable.
And finally, if you've bought an expensive car like the Tesla, you may be more likely to drive it more carefully than the average person does their Honda Accord.
I don't think Musk is any more dishonest than any other CEO, and he's probably more honest, by far, on average. However, it kind of pains me to see how easy it is for him to sway the hacker crowd with data-interpretations that would be questionable by any standard. If this is among the strongest empirical evidence he can provide, then I think we should maintain some skepticism.
For whatever reason BMW stood out most of all as the worst of the worst in this study, but 'expensive car drivers are better drivers' has been proven to not be an assertion you can make from common sense or intuition.
1. We can't assume that Tesla drivers are the same as traditional luxury car drivers. While cars are a statement of wealth, and many arrogant bastards like making that statement...A Tesla is ostensibly a statement of a few other things, such as concern for the environment, optimism about technology, etc. etc...in the same way, even though many programmers make high-end salaries (low-6 figures), I wouldn't say that we can expect these programmers to golf as much as the average non-programmer low-6-figure-earner.
2. Reading the link you posted, it said the study evaluated based on the frequency of accidents and the size of payout...I couldn't find the study on the website, but this statement from the article was ambiguous to me:
> According to data from IIHS website, the collision insurance losses on BMW 7 Series are more than twice the average for vehicles nationwide, and BMW 3 Series two-doors are more than three times.
Twice the average of what...? Payouts total? Payouts per claim? Payouts per claim normalized by number of total cars of that kind on the road?
3. The NHTS data concerns the number of fires. For the study you cited to be more relevant, we'd have to know what proportion of the insurance claims also involve vehicle fires. If you're thinking, "Well, if a car caught on fire, then that's likely because of an accident...so more accidents mean more fires"...well, a> That's a classic logical fallacy (All dogs are animals. Sara owns a lot of animals. Therefore, Sara owns a lot of dogs) and b> the kinds of accidents that make up a majority of insurance claims (my guess is low-to-medium speed fender benders) may not represent a significant portion of incidents that end up in a flaming wreck.
All in all, I wouldn't say that Musk is clearly wrong here...He could be right, we just don't have enough information either way...so it feels slightly dirty -- a slap in the face of analytical thinking -- for him to cite these statistics as being anywhere near conclusive.
I firmly believe that what's happening on the stockmarket and the fire are merely a coincidence, there isn't a causal relation between them. Tesla stock has been due to correct back for a while, and a downgrade came in as well (unrelated to the fire).
Edit: first rule of the HN club: only positive things about Tesla, otherwise you are going to be voted down. Neutral opinion is considered negative. :)
If the battery really was punctured by an unfortunately placed piece of metal in a sort of surprising scenario, we ought to stratify by collision type in order to really understand the problem. How do gas cars perform during a gas tank puncture? At similar speeds? And how common are such collisions? The relevance of this consideration is expressed by Simpson's paradox:
I.e. analyses of performance when conditions differ ought to take into account those conditions, at least when they are both a: known (true in this case) and b: not causally connected to the variable under consideration (also true in this case).
A good point. It would be interesting to compare the miles drive on "brand new expensive cars" not just all cars which include obviously older and/or poorly maintained vehicles.
Agreed, there's insufficient data for meaningful statistics, but his main points were amour-plating, firewalls and that batteries are less fire-prone than "highly flammable liquid".
The 30,000x larger sample in the aggregate means the calculated fire rate for non-Tesla cars is probably a more reliable number. Maybe those 100M Tesla miles were "lucky"? Possibly not, though - I don't know enough about cars to guess.
The 3 trillion aggregate miles includes a lot broader sample size of car age than those from a single company that's 10 years old. This, to me, seems important to control for.
Finally - I bet the usage profile of a Tesla is different from the median usage profile of every random car on the street and throughout the country.
It takes a LOT of force to pierce 1/4 inch plate. My boat weighs 12 tons, and it hardly has a dent from the collissions I and previous owners have been in.
I was simply sharing my personal experience with ramming 1/4 inch plated vehicles into hard immovable objects to give some perspective as to what kind of strength we're talking about.
It would have been nice to include a little, more personal, summary. Something like:
In this extreme test, we feel that the car performed as designed and we are very happy that the car owner safe.
Edit: the original parent said that the tone of the Tesla posts seem defensive. I'm not really sure what was wrong about the comment... they do seem a little defensive in tone. (Often understandably so...)
I would only point that 25 tons of force, isn't really a lot - I mean, the small jack that you use to lift your car can be a 5 or 6 ton device.
You have a vehicle traveling a decent rate of speed, for it to strike or run over anything at all will involve tons of force.
Neat explanation of the sort of math involved, with both SI and US units http://hyperphysics.phy-astr.gsu.edu/hbase/carcr.html . In the example, a car going 30 mph (50km/h) striking a tree will hit with about 48 tons of force.
Floor jacks easily punch through most points on modern cars. In fact, the only place that it is safe to jack up your car are special jack points which are reenforced to bear the load of the jack. The center ones on my car are pretty annoying to get to. Also, your estimate for the ratings of jacks is off by a factor of x2 to x4. Floor jacks, which have a leaver and a hydraulic component, are typically only rated for 2 to 3 tons. Scissor jacks, a manual jack that comes with your spare tire, are typically only rated at 1.5 tons or less.
It's not clear to me why you'd say it's not a lot of force while making the comparison to a jack. Take a jack and use it under the wrong spot on a vehicle and you might get a pretty painful display of vehicle penetration, which is what we're really talking about here.
Just to put it into explicit perspective.
A jack, although maybe rated to 5 tons, is unable to pierce the bottom of my car at 25 tones of force because my car only weighs 1.5 tons. I'd have to run over something at speed that angles upwards after I drive over it, or drop my car onto something sharp (at 35km/h) to achieve a similar force.
Regardless of Musk's statement, a gasoline powered car would not have suffered a fire most likely in this incident as its fuel source does not stretch to the front of the vehicle. More than likely the debris would have done some serious damage to the underside of the car, if any. There is a lot of open, hollow, space in the underside of most modern cars.
He is handling it wrong by trying to tell people that this car fire is not anything special. Seeing that the fire department had to do quite a bit to contain it means his cars will burn to the ground just like any gasoline car will. I doubt any fire will leave the car in any state but salvage.
"A fire caused by the impact began in the front battery module – the battery pack has a total of 16 modules – but was contained to the front section of the car by internal firewalls within the pack."
If the fire was able to jump cells, does this make the battery pack "fundamentally unsound", as Elon has described the Boeing battery? Not necessarily. However, merely puncturing the gas tank of a ICE car in this way is not guaranteed to set the gasoline on fire. The ignition temperature of gasoline is over 500 F and the gas tank itself is plastic, most likely. Gasoline vapor is explosive, but the car was traveling fairly rapidly and a there's a fair amount of wind to dispel vapor. The ignition source would have to be heat from the metal of the debris self-striking metal of the debris, or though both layers of plastic to the auto frame itself, and that spark would have to find some gasoline, which is pooled at the bottom of the tank and not near the top. I suppose it's possible. Car crashes do produce burning gasoline, though usually it's a very severe crash that mixes gas vapor with the heat of the engine.
This is worth noting. The fire did not stop and kept reignighting. The FD had to flip the car on its side and physically gain access by cutting the car up, to put the fire out. Under this scenario, it seems dubious that compartmentalization would be sufficient. Thermal conductivity at some stage would overcome the situation.
Also, you are right to highlight that petrol fuel systems are a cause only on a tiny minority of real-life auto accident related fires (~2%). The safety of petrol engines is actually quite high in this regards (counter-intuitive, perhaps). Plastic has the ability to deform rather than crack (flexibil vs brittle) and also the position of the fuel cells is much more protected. Think about the debris from front-tires -- much more likely to hit the undercarriage (where the Tesla battery is) than behind the rear axel (where many tanks are). Debris hit by the rear tires of course exits behidnd the car in either scenario. This setup is obviously not by chance. The Li Ion battery is probably low for COG reasons and fore-aft weight distribution. Li ION is much heavier than petrol.
My conjecture: The Model S is a heavy car. Hit something pokey at speed and you've got an awful lot of forces channeled to a point.
I also thought it a bit much that Musk tried to compare this to severing "fuel supply lines" in a gas car. The likelihood of a 3 inch puncture severing a fuel line or entering the gas tank is vastly lower than compromising a battery pack that runs the length of the underside of the car.
The Tesla's underbelly vulnerability zone is vastly larger than fuel tanks and lines.. and a punctured battery doesn't need an ignition source to start a fire, either.
First of all, most automotive gas tanks are made out of ~1/8" HDPE. While it has decent cut and abrasion resistance, it's of virtually no use when trying to combat punctures and is also pretty flimsy, leading to deformation and possible cracking during an accident.
While, yes, a punctured battery pack is guaranteed to ignite while a gas tank is not, that is also the only way for the pack to ignite. An object has to physically pass through the battery pack, while a gas tank could potentially start a fire if it cracks and starts leaking. There's a reason why you're supposed to try to get out your car as quickly as possible in case of a crash: fuel leaks very easily. In comparison, batteries are much more impact resistant due to their more solid state nature.
Also, it seems that whatever struck the car seemed to hit under or very close to where the front passengers sit. Had that armored battery pack not been there, there's a very real possibility that the driver would have been impaled. With that in mind, it should be pretty clear that this was a freak accident and not really representative of the average car crash.
AFAIK, all the Lithium Ion Battery electrolytes are flammable (they are pressurized in the battery container too). Depending on the chemistry of the Lithium-ion battery that Model S uses, some (I.E. LFP) are safer than the others, but still, 1% potential?
EVs like Chevy Volt, Fisker Karma and even Boeing 787 Dreamliner and UPS/FedEx freight flights had been caught Lithium fires in air before.
The total combustion energy of the battery pack is only 10% of that of the petrol tank in a petrol-fueled vehicle partially because the energy density of Lithium-ion cells is significantly less than petrol or diesel fuel, which is why the Model S has half the range of similar conventionally fuelled cars in it's class. I'd also speculate that he's only measuring the combustion energy of the hydrogen that could escape & ignoring any electrical heat generated. The control systems on the batteries ought to cut the connections to the cells if they detect a short of course, but no system is perfect & he's very careful to use the more specific term "combustion energy".
Maybe. When the dreamliner battery fire happened, had quite a bit to say regarding batteries and cascading failure. He's surely making some assumptions (such as discounting an external factor as you state), but it's not like he isn't on record asserting they have put some effort into preventing or mitigating this exact problem.
Gasoline is about 12kWh/kg or 9kWh/l (http://en.wikipedia.org/wiki/Gasoline#Energy_content)
So, that 85kWh battery, when driving an engine, is equivalent to about 10 liters of gasoline. I guess that's more or less what could get released in a fire (corrections welcome; I don't know what kind of factor that 'effective' could introduce)
If that logic stands, to get at 1%, the typical car would have to have 1000 liters of gasoline on board (for the metric impaired: that's over 250 US gallons/over 200 imperial gallons). That, clearly, is unrealistic.
Elon may have knowledge of the loading state of the battery, but if so, I think he should have mentioned that. Gasoline tanks aren't 100% full all the time, either.
The less gas a tank has, the more dangerous it could be. It's a common mistake to think a close to empty tank of gasoline is safer than a full one when the reverse may be true because of the fumes.
So basically if you want it to explode hollywood style, then you need gas vapors, but if you want a very bad car fire, then you need lots of gas.
Lots of gas can do much more - say, if a gas lorry spills under a concrete bridge, then the fire can do structural damage to that.
I suspect that more people are killed by big flames than explosions, but more fire fighers are killed by explosions than big flames.
In contrast, the combustion energy of our battery pack is only
about 10% of the energy contained in a gasoline tank and is
divided into 16 modules with firewalls in between. As a
consequence, the effective combustion potential is only about
1% that of the fuel in a comparable gasoline sedan.
1. I have had my gasoline car catch on fire in my lifetime. (That was the end of the car.) However, it was having a lot of trouble at the time and we had just taken it to the mechanic. (That's right, it caught on fire at the mechanic's shop. We were still waiting to talk to the mechanic before going back home when it caught on fire.) This was not the only on-fire incident among our friends. One had his minivan catch on fire in a gas station.
But both of them were old cars. What is to say that most of the cars that catch on fire aren't much older than the Tesla? What is to say that the Tesla won't have more trouble as it gets older?
Oh yeah. The batteries will have to be replaced before the car is run down as much as our old beaters were. And Tesla owners will have the money to maintain their cars better than we did as teenagers.
So, what I'm saying is that the real test will be in a decade. More fires will probably happen, just like regular cars do.
Either way, it's probably not dangerous enough to be worth avoiding buying a new one.
Otherwise it looks like making excuses and that is bad.
Much of that danger is inherent to the way the system works and the current level of technology and the costs people are willing to pay. A single car maker will never be able to get anywhere remotely close to airliner levels of safety.
That means that Tesla's products will be used in dangerous circumstances, and Tesla customers will die while using their product.
For a normal car company, this would not be a problem, because the public accepts the current risks of automobile travel. The problem is that Tesla is Different and gets far more scrutiny.
Tesla needs to convince people to accept the risks inherent in using their products. Pointing out that people accept the even greater risks inherent in using their competitors' products is a perfectly reasonable thing to do.
Fact is, there are thousands of people who die every year in motor vehicle accidents. Gas tank leaks and fires are a nonzero portion of those accidents.
A battery fire, especially one where the driver walked away unharmed, is only news because it's the first one for Tesla. How is putting things in perspective to be construed as redirection or deflection?
In the meanwhile, Car companies are notorious for denying anything's wrong:
He seemed to skip that last bit. (?)
All cars: 1 fire per 116 million vehicle miles/year
Tesla: 1 fire per 113 m vehicle miles/since inception
Obviously, the Model (s) being a newer Tesla model does not have the full historical amount of "Tesla" Miles as the denominator.
 Furthermore, only 2% of non-deliberate fires start in the fuel line or fuel tank of a normal vehicle
They've always published First Responder fact sheets for their cars which talk about how firefighters should handle a battery on fire.
We all know there is negative rhetoric bouncing around about this incident. It seems to me that, precisely because of this, there really isn't a need to write in such a manner—trying to block all possible avenues of attack as if one is a afraid of what will be written in response.
The tone, to me, betrays insecurity, and this seems something at odds with the bullish, innovative nature of the non-PR aspects of the business.
- All Tesla cars are new and almost all of them have superior drivers.
- They drive their cars only on certain roads where as Gasoline cars are almost everywhere.
- You can not compare 100m sample set with 2 trillion size sample set.
And who would have thought a side-effect of disrupting the automotive industry would be training fire-fighters on the correct techniques for battling a lithium fueled fire?
That being said, If that part had punctured a gas tank of a petrol vehicle the damage could've been explosive or caused a fire also.
I like how they have calculated how this happened because that most likely means in the next revision they may improve the skid plate or the battery wall to protect it from such things. Or recall them and retrofit, if needed. They aren't being mysterious like I've seen from other auto manufacturers. But then again, not every company dives in $1B in worth after a car has an accident.
Mythbusters did it:
Although, there was the Pinto, which was just poor design: https://www.youtube.com/watch?v=qZDVqhWGILA
source: the same one Musk quoted.
Then there's this: http://articles.baltimoresun.com/1993-03-23/features/1993082...
But I know what you mean. You mean the hollywood explosion. That's not real life.
It sounds more like they're congratulating themselves on designing the failure to be so easily contained.
Diesel-powered car would be much safer, since oil requires something like a wick in it to burn. It's hard to argue with Tesla's statement, since argument is true; but it doesn't include this issue in electric vs ICE vehicle competition.
I LOVE THE COMPANY. I DON'T ENJOY OR APPRECIATE THE LAME MARKETING ATTEMPTS THEY SOMETIMES MAKE. Just like that whole business of jumping through hoops to make it seem like there was some new magical way to finance a Tesla, this is wrong.
Trying to create a safety metric by comparing the number of fires to the number of miles driven per vehicle type is pure nonsense. You have to look at the causes and mechanisms of the fires and dig a lot deeper than that in order to even hope to generate a meaningful metric.
Here's an imperfect analogy (numbers made-up): One million people run marathons every year world wide. 1000 have heart attacks and die. Ten thousand people have run marathons with our shoes and only one had a heart attack and didn't die. You are far less likely to have a heart attack and die if you run marathons with our shoes.
Almost anyone would look at that and recognize it as a poor attempt to create a nexus where one does not exist. I think it's bad marketing.
Now, if we started to dive into the statistics and identified location, weather conditions, age, physical conditioning, pre-existing conditions (heart problem they did not know about), etc. we might actually be able to attempt a comparison between people wearing the new shoes vs. the other brands. Even then, the nexus would be tenuous at best.
A similar exercise would be needed to compare car fires between brands and types with any degree of validity. I don't have the time to dive into the stats. It was easy enough to Google  and do a quick scan:
It is easy to see that young males are more likely to be involved in a car fire.
There are statistics about different brands having different fatality rates (not necessarily related).
Lots of fires are caused by running equipment. Lots of fires originate in the engine compartment. Mechanical and electrical failures seem to account for over 60% of fires.
The point is simple: Far more extensive and detailed statistical work needs to be undertaken before anyone can conclude absolutely anything on the merits of any particular car or design as it pertains to potential to cause fires.
Elon and his team are very smart. They know this. And this is why some of their marketing of late feels really dirty and beneath them. This is Tesla reacting to news that affected their stock price and, potentially, buyer sentiment, with marketing rather than the truth.
Are Tesla's safer than all gasoline cars? That question is probably not an easy one to answer at all.
There's the potential for a theoretical sort of an answer based on design. For example, there are no fuel lines to rupture. Does that mean it is safer? Hard to say. What do you compare that to? Perhaps you can list all the potential sources of ignition and sort them by probability and MTBF? Not sure.
Of course, then you have the real-life probability. Once you get a million cars on the road with all kinds of people, driving in all conditions, roads and levels of maintenance and neglect things can change dramatically. If I remember correctly Tesla has somewhere in the order of twenty thousand. There's a reason we see major car companies recall hundreds of thousands of cars every so often. Shit happens. Design error are made. And it can take time and a massive installed base to discover them.
THE TRUTH OF THE MATTER is these are the kinds of tests electric cars will have to endure over a period of time in order to reach wide adoption. Despite what's been said here a full tank of gasoline is far safer than a fully charged battery pack with enough energy to go 300 miles.
Before anyone mauls me, consider how many gasoline cars have been driven and, yes, crashed, world-wide since gasoline cars came into mass production. Not last year. Since forever.
There have probably been millions of accidents without fires, even with fuel leaks. There's probably no imaginable way to compare the two at this time. We simply don't have enough data. And, no, linking to a horrible crash video on youtube involving gasoline igniting does absolutley nothing to support arguments on either side.
The one issue with electrics that is not spoken of is the fact that you have a several hundred volt high energy system that could very well electrocute passengers. I fully expect that to happen one day (in general, not necessarily Tesla). If and when that happens you can bet it will set the breaks on electrics for a while and relevant stocks will plummet.
I still believe electric cars are the future. We simply need to go though the evolutionary process that will make them really safe for hundreds of millions of electrics to share the road. What happens when you have a pile-up of ten or twenty electric cars on a fogg-covered highway? A pile of mangled wrecks with 400 Volt high energy systems is unimaginably dangerous. I can think of a few horrific scenarios under those conditions.
At some level part of me thinks that fuel cells are the future, not batteries. Having something relatively benign that can leak out would be a good thing.
A few months ago there was a horrific crash in my neighborhood. This 18 year old kid decided it was OK to go 100 miles per hour on this avenue. He lost control and plowed into a bunch of cars parked by the side of the road. He absolutely destroyed seven of them before coming to a stop. Most of the cars were mangled beyond recognition. He was driving an SUV with a lot of mass. His SUV was nearly cut in half and impaled into one of the cars to a degree that made it difficult to see where one car started and the other ended. Almost like taking two lumps of play-doh and mixing them together.
No fire. Gasoline all over the place but no ignition at all. He hit the first car, fused into it and the "ball" formed by the two cars proceeded to destroy the other six. Absolutely amazing display of how much kinetic energy was dissipated.
Had this been eight fully-charged electric cars I am almost certain there would have been a horrific fire as well as the potential for absolutely impossible to describe electrocution of some of the passengers. And, to make matters worst, it would have taken the rescue crew far longer to remove the victims as they would have to be worries about electrocuting themselves and the victims (at the very least).
Until there are enough electric cars on the road to have a massive pile-up accident  where most cars are electric we will not really understand the practical reality of a world where every car on the road is electric. Imagine having to walk out of a one hundred mangled car pile-up where every car has a battery pack storing enough energy to drive 300 to 400 miles and they are wired to produce hundreds of volts. I can't imagine anyone who understands electronics and electricity that would tell me all would be well after looking at the pictures from this accident  if all cars were electric. Look at pictures 1, 8 and 11. No fires. Gasoline isn't all that bad in this regard.
Fuel tanks/lines and related systems cause only ~2% of Automotive fires in the US (excluding intentional ones).
Elon Musk & Tesla would review its design, would possibly add protection for these type of accidents.
Will any other gasoline car manufacturer be willing to participate in such crash test what model S encountered, I doubt anyone will.
crafty writing. read it as "high speed"
(Knowing the Elon is the Sun God among many here, I want to say this: I do not particularly care about karma, I'm saying 100% of what I am thinking.)