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Tesla Model S achieves best safety rating of any car ever tested

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Re: Tesla Model S achieves best safety rating of any car ever tested

#291

Post by dredmorbius »

jacquesm wrote: post #159
dredmorbius wrote: post #121

Earlier quoted context omitted.

Interesting. The change is almost totally attributable to ESC (electronic stability control), which directly addresses SUV's Achilles' heel. It's also interesting to note the variability in results -- the Audi A6 is one of the safest luxury vehicles (I suspect the Tesla S will change that), and the Honda Accord is remarkably safe for a mid-sized sedan (though the Civic doesn't do as well relative to its class). It's…

That's per million vehicle years not per million miles. When I read your comment I realized something must be off and went to check the source data. Imagine if the average driver drives 20K miles / year it would take only 50 drivers to get to million miles. If the death rate of cars would even approach 50 deaths per million miles then everybody would stand a good chance of dying in a car accident. Clearly this is not…

Thanks for the clarification.

For some stats:

In 2009 there were 10.5 million accidents, and 35,900,000 motor vehicle fatalities. Your odds of dying in any given accident are 0.3%.

In 2013 projections were for 1,203.6 billion vehicle miles travelled. Travel mileage has actually been declining slightly (about 1%/year) since the 2008 depression.

You could expect to travel 33,526,462 without a death, on average.

http://advisorperspectives.com/dshort/updates/DOT-Miles-Driv... https://www.census.gov/compendia/statab/2012/tables/12s1103....

Re: Tesla Model S achieves best safety rating of any car ever tested

#292

Post by nzealand »

JshWright wrote: post #209
sitharus wrote: post #120

Earlier quoted context omitted.

> All I'm saying is, never trust Elon Musk PR to tell you the whole picture. Never trust anyone's PR to give you the whole picture! Though as a counterpoint, I've seen cars with the roof cut off to extract people, but never the side doors or the floor cut open. I don't think they'd cut the floor since it's quite thick and has all sorts of wires and pipes anyway.

Firefighter here... The major thing that concerns me about the Model S is the placement of the DC-DC converter in the front right wheel well. There's a common maneuver called a 'dash lift' where you make a couple relief cuts and then lift the dash using a hydraulic ram. Properly place, those cuts are dangerously close to that high voltage system. Explanation of relief cut placement: http://advancedextrication.com/201…

Looks challenging. How does that compare with a Prius?

Re: Tesla Model S achieves best safety rating of any car ever tested

#293

Post by icelancer »

abalone wrote: post #142
agumonkey wrote: post #137

Earlier quoted context omitted.

And I guess it's unrealistic to think of a special draining device to be brought on crash sites to exhaust the car battery. All in all, are electric vehicles more 'instable' energy wise when crashed, compared to petroleum based one ? or is it different flavours of similarly sh*tty situations ?

That's a very big question and probably only time will tell. Without getting into it too much, a very basic difference is.. Gas can explode like a bomb but (a) it needs an ignition source and (b) there can be visible signs when the fuel is leaking to let you know to take extra precautions (like spray fire retardant). You can actually get fuel on you and you'll be fine. High voltage systems don't (usually) explode, bu…

>Basically Tesla deserves props for making an extremely strong car. That's what was tested here. But the spin is they're claiming "safest car" while completely side-stepping the high voltage safety issue.

That's not a side-step. IIHS doesn't test for this, and Tesla is not beholden to do so.

Re: Tesla Model S achieves best safety rating of any car ever tested

#294

Post by _mulder_ »

klinquist wrote: post #122
curiousDog wrote: post #39

Earlier quoted context omitted.

Not exactly a diagram but the a video of the test: http://www.youtube.com/watch?v=dz2FMfv-CSc A bmw 3 series (not full frontal): http://www.youtube.com/watch?v=4XG8BQt4sHY

0:58 - 1:07 of the first video link... the car continues to attempt to propel itself into the wall.

Only for 0.3 seconds. The first camera shot at normal speed show's how quick this is all happening.

Re: Tesla Model S achieves best safety rating of any car ever tested

#295

Post by DavidWanjiru »

Is there not a way an emergency responder, or anyone else for that matter, could fully discharge a battery like the one on a Tesla? As ask coz back in the day before digital cameras became mainstream, we used to repair point and shoot cameras at the photo processing lab where I worked. A point and shoot camera has a capacitor for the flash that can give you a short but not insignificant shock, and to avoid it, we'd take a normal light bulb and use it to discharge the capacitor. I realize a cap batteries stores a lot more power, but couldn't some mechanism be built that does the same thing?

Re: Tesla Model S achieves best safety rating of any car ever tested

#296

Post by simonh »

nitrogen wrote: post #124
kbar13 wrote: post #117

Earlier quoted context omitted.

is randomness not good? you aren't going to be driving around on a rail irl

Not when you're trying to make an objective comparison with a small number of trials.

If the test was always exactly the same, designers could optimize the car design for that precise impact force at that precise point.

Re: Tesla Model S achieves best safety rating of any car ever tested

#297

Post by JshWright »

nzealand wrote: post #292
JshWright wrote: post #209

Earlier quoted context omitted.

Firefighter here... The major thing that concerns me about the Model S is the placement of the DC-DC converter in the front right wheel well. There's a common maneuver called a 'dash lift' where you make a couple relief cuts and then lift the dash using a hydraulic ram. Properly place, those cuts are dangerously close to that high voltage system. Explanation of relief cut placement: http://advancedextrication.com/201…

Looks challenging. How does that compare with a Prius?

A Prius is a lot simpler. All the electric components are well away from all the 'usual' cut locations.

Obviously all the normal concerns apply (air bags, pretentioners, etc), but from an extrication perspective, they're pretty straightforward.

The one issue common to all EVs (hybrid or plugin) is that the can silently deliver power to the wheels. With a 'normal' car, you can hear the engine running. With an EV, it can be harder to tell if it's on or not.

One of the first things we do it secure the keys, but with keyless ignition, the key may be trapped in the drivers pocket. That means the big round 'On' button just needs to be bumped by someone for the car to power up. That's why it's critical that we're able to disable the electrical systems of the car, to prevent it from starting up unexpectedly.

Re: Tesla Model S achieves best safety rating of any car ever tested

#298

Post by mncolinlee »

agumonkey wrote: post #127
RomP wrote: post #22

This is simply unkind to the competition (and to the poles alike): "Tesla achieved this outcome by nesting multiple deep aluminum extrusions in the side rail of the car that absorb the impact energy (a similar approach was used by the Apollo Lunar Lander) and transfer load to the rest of the vehicle. This causes the pole to be either sheared off or to stop the car before the pole hits an occupant." There's winning an…

Is it too far fetched to say he benefited from SpaceX research ? if so, this kind of gene transfer reminds me of Apple years when the iPhone benefited from iPod and Mac hard and software knowledge to leapfrog the competition, and then later helped the MBA do it again.

I would imagine this is less the case than Subaru and Saab benefiting from their own aeronautical research. Unlike Subaru and Saab, SpaceX is a different company with different engineers than Tesla.

Rather, I think this speaks more to Elon Musk's uncanny ability to attract and hire good engineers.

Re: Tesla Model S achieves best safety rating of any car ever tested

#299

Post by ErsatzVerkehr »

chongli wrote: post #286
ErsatzVerkehr wrote: post #161

Earlier quoted context omitted.

That's the amount of energy needed to bring nearly 1000 kg of water from 25°C to 100°C, but not enough to begin the phase transition from liquid to gas (i.e. start boiling). The heat of vaporization of water (i.e. the amount of energy required to convert liquid water at 100°C to vapor at the same temperature) is 2260 J/g. So to completely boil your metric ton of water at 100°C would require an additional 1000 kg * (2…

While that's true, I don't think it's what the parent meant. Colloquially, when we say to boil water we don't mean until the vessel is dry , just until a roiling boil is reached (this is typically how we cook pasta).

If the 1000 kg is heated uniformly, this is not enough energy to bring it to a "roiling boil". There will be no bubbles.
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