QuoteSmall cars get poor marks in collision tests
By KEN THOMAS, Associated Press Writer Ken Thomas, Associated Press Writer Tue Apr 14, 6:46 am ET
WASHINGTON – Micro cars can give motorists top-notch fuel efficiency at a competitive price, but the insurance industry says they don't fare too well in collisions with larger vehicles.
In crash tests released Tuesday, the Insurance Institute for Highway Safety found that drivers of 2009 versions of the Smart "fortwo," Honda Fit and Toyota Yaris could face significant leg and head injuries in severe front-end crashes with larger, mid-size vehicles.
"There are good reasons people buy mini cars. They're more affordable, and they use less gas. But the safety trade-offs are clear from our new tests," said Adrian Lund, the institute's president.
Automakers who manufacture the small cars said the tests simulated a high-speed crash that rarely happens on the road. They also said the tests rehashed past insurance industry arguments against tougher fuel efficiency requirements. The institute has raised questions about whether stricter gas mileage rules, which are being developed by the government, might lead to smaller, lighter vehicles that could be less safe.
"If you were to take that argument to the nth degree, we should all be driving 18-wheelers. And the trend in society today is just the opposite," said Dave Schembri, president of Smart USA.
Sales of small cars soared when gas prices topped $4 per gallon last year but have fallen off as gasoline has retreated to about $2 a gallon and the economic downturn has slowed car sales. The small cars are affordable — prices of the three cars tested range from about $12,000 to $18,000 — and typically achieve 30 miles per gallon or more.
The tests involved head-on crashes between the fortwo and a 2009 Mercedes C Class, the Fit and a 2009 Honda Accord and the Yaris and the 2009 Toyota Camry. The tests were conducted at 40 miles per hour, representing a severe crash.
In the fortwo collision, the institute said the Smart, which weighs 1,808 lbs, went airborne and turned around 450 degrees after striking the C Class, which weighs nearly twice as much. There was extensive damage to the fortwo's interior and the Smart driver could have faced extensive injuries to the head and legs. There was little damage to the front seat area of the C Class.
Schembri said the test simulated a "rare and extreme scenario" and noted that the fortwo had received solid ratings from the government's crash test program. The fortwo has received top scores from the Insurance Institute in front-end and side crash tests against comparably sized vehicles but in the front-end tests against the C Class, the institute gave the mini car poor marks.
In the Fit's test, the dummy's head struck the steering wheel through the air bag and showed a high risk of leg injuries. In the vehicle-to-vehicle test, the Fit was rated poor while the Accord's structure held up well.
Honda spokesman Todd Mittleman said the tests involved "unusual and extreme conditions" and noted that all 2009 Honda vehicles had received top scores from the Insurance Institute.
In the Yaris test, the institute said the mini car sustained damage to the door and front passenger area. The driver dummy showed signs of head injuries, a deep gash on the right knee and extensive forces to the neck and right leg.
The Yaris has received good ratings in past front and side testing but received a poor rating in the crash with the Camry. Toyota spokesman John Hanson said the car-to-car test had little relevance to consumers because of its severity.
"It's fairly obvious that they have an agenda here with regard to how smaller cars are going to be entering the North American market in larger numbers," Hanson said.
___
On the Net:
Insurance Institute for Highway Safety: http://www.iihs.org/
It always dumbfounded me why frontal crash tests only used to test for the collision with a vehicle of the same size. If I drive a Smart car, then I would have to look for months to find another Smart car to crash head-on into. Therefore, its excellent front impact ratings are of little benefit in a type of crash that is most likely to be fatal. I think the comments from carmakers in this article are more than just a little disingenuous, and dangerously misleading.
On the other hand, advocating large cars for safety is really advocating an arms race. The reason why small cars are more dangerous is precisely because there are heavier cars out there to crash into. Therefore by getting a big car for safety you're taking away from the safety of other drivers.
QuoteTherefore by getting a big car for safety you're taking away from the safety of other drivers.
(https://languish.org/forums/proxy.php?request=http%3A%2F%2Fxs138.xs.to%2Fxs138%2F09162%2Fcounterpoint565.jpg&hash=53d1a13ab8c1e6f3f208232c1d17b2884fe5eeac)
I say...Screw them. Let 'em crash.
Actually, the original IIHS article refutes my point. While it would help to have every car be small, the smaller cars are still far more dangerous even in single car collisions. That's because heavier cars can deform the objects they hit better, and thus decelerate less abruptly. This makes me question the point of safety ratings even more, since most small cars get good ones these days, and yet the death rate is much higher in them.
Quote from: DGuller on April 14, 2009, 10:26:08 AM
Actually, the original IIHS article refutes my point. While it would help to have every car be small, the smaller cars are still far more dangerous even in single car collisions. That's because heavier cars can deform the objects they hit better, and thus decelerate less abruptly. This makes me question the point of safety ratings even more, since most small cars get good ones these days, and yet the death rate is much higher in them.
Moreover, there are plenty of vehicles out there that cannot be made smaller. Buses, dump trucks, tractor-trailers, steamrollers, etc.
That's a bummer. But also, duh? Physics?
Smart cars on the highway. :bleeding:
Duh. Isaac Newton knew that 300 years ago.
As I said, the big shock to me is how dangerously misleading the official safety ratings are. Yes, they do make a disclaimer that frontal impact results can be compared only against like cars. However, would you really know from that disclaimer that a car with perfect safety ratings can still be up to three times as likely to kill you compared to a heavier car?
Aren't the frontal crash tests usually done against a concrete barrier which is presumably the same for all cars?
Quote from: Zanza2 on April 14, 2009, 12:09:20 PM
Aren't the frontal crash tests usually done against a concrete barrier which is presumably the same for all cars?
Yes?
Why don't they make rubber cars?
Quote from: Jos Theelen on April 14, 2009, 12:20:23 PM
Why don't they make rubber cars?
Rubber is a terrible structural material. Imagine your shock when the rubber that your seat is bolted to gives way and throws you, seat and all, through the windshield.
Quote from: DGuller on April 14, 2009, 12:13:21 PM
Yes?
So why is the result only valid against a car of similar size?
Quote from: DGuller on April 14, 2009, 11:58:46 AM
As I said, the big shock to me is how dangerously misleading the official safety ratings are. Yes, they do make a disclaimer that frontal impact results can be compared only against like cars. However, would you really know from that disclaimer that a car with perfect safety ratings can still be up to three times as likely to kill you compared to a heavier car?
Crashes often involve things like trees, trucks or pillars which are not going to give way, no matter how big your car is. In that sense the standard test is much more accurate.
Mind you, the article is unclear on a very significant point, I suspect these car to car tests were carried out at a combined velocity of 80 mph. That is a lot, and it is no wonder lighter cars suffer heavily, since they experience much more decel than in standard tests against a barrier, thus the comments from the manufacturers.
Quote from: DGuller on April 14, 2009, 11:58:46 AM
As I said, the big shock to me is how dangerously misleading the official safety ratings are. Yes, they do make a disclaimer that frontal impact results can be compared only against like cars. However, would you really know from that disclaimer that a car with perfect safety ratings can still be up to three times as likely to kill you compared to a heavier car?
That is scary and the comparisons here were just between the very small cars and mid size cars, not vs large cars or large SUVs. Plus the single car accidents hitting trees, poles or what ever which can be bad; I kind of think those kinds of accidents aren't counted in the safety stats? Not sure though. Cars are a lot safer though over all.
Quote from: Zanza2 on April 14, 2009, 12:33:40 PM
Quote from: DGuller on April 14, 2009, 12:13:21 PM
Yes?
So why is the result only valid against a car of similar size?
The physics of a car hitting an immovable object at 40 mph is equivalent to the physics of the car hitting another car of the same size head-on when both are going 40 mph in opposite directions.
Quote from: Iormlund on April 14, 2009, 01:13:41 PM
Mind you, the article is unclear on a very significant point, I suspect these car to car tests were carried out at a combined velocity of 80 mph. That is a lot, and it is no wonder lighter cars suffer heavily, since they experience much more decel than in standard tests against a barrier, thus the comments from the manufacturers.
If two cars of the same weight crash at 80 mph combined velocity, then the result is the same as crashing one car at 40 mph into immovable barrier. They shouldn't experience more deceleration in one test compared to another.
The small cars will suffer more damage in car-to-car tests if crashed against bigger cars, but that was the whole point. In the real world, if you're in a small car, you're likely to crash into a bigger car when you have a head-on, not into a car of the same size.
Quote from: DGuller on April 14, 2009, 01:57:05 PM
Quote from: Iormlund on April 14, 2009, 01:13:41 PM
Mind you, the article is unclear on a very significant point, I suspect these car to car tests were carried out at a combined velocity of 80 mph. That is a lot, and it is no wonder lighter cars suffer heavily, since they experience much more decel than in standard tests against a barrier, thus the comments from the manufacturers.
If two cars of the same weight crash at 80 mph combined velocity, then the result is the same as crashing one car at 40 mph into immovable barrier. They shouldn't experience more deceleration in one test compared to another.
That's impossible. You can't bypass the laws of physics.
Quote
The small cars will suffer more damage in car-to-car tests if crashed against bigger cars, but that was the whole point. In the real world, if you're in a small car, you're likely to crash into a bigger car when you have a head-on, not into a car of the same size.
I guess that depends largely on your city. On mine it is rare to drive on a fast, two-way street that has no physical separation in the middle. Crashing onto a tree or a lamppost is much more likely than into oncoming traffic.
Quote from: Iormlund on April 14, 2009, 02:53:57 PM
Quote from: DGuller on April 14, 2009, 01:57:05 PM
Quote from: Iormlund on April 14, 2009, 01:13:41 PM
Mind you, the article is unclear on a very significant point, I suspect these car to car tests were carried out at a combined velocity of 80 mph. That is a lot, and it is no wonder lighter cars suffer heavily, since they experience much more decel than in standard tests against a barrier, thus the comments from the manufacturers.
If two cars of the same weight crash at 80 mph combined velocity, then the result is the same as crashing one car at 40 mph into immovable barrier. They shouldn't experience more deceleration in one test compared to another.
That's impossible. You can't bypass the laws of physics.
Elaborate.
Quote from: Iormlund on April 14, 2009, 02:53:57 PM
That's impossible. You can't bypass the laws of physics.
I'm not trying to. In what way do you think I'm bypassing the laws of physics?
A friend of my wife's bought a smart car. Definitely one of the most inappropriately named vehicles ever.
Quote from: Iormlund on April 14, 2009, 02:53:57 PM
That's impossible. You can't bypass the laws of physics.
Quote from: About.ComForce - Colliding With a Wall
Consider case A, in which car A collides with static unbreakable wall. The situation begins with car A traveling at a velocity v and it ends with a velocity of 0. The force of this situation is defined by Newton's second law of motion. Force equals mass times acceleration. In this case, the acceleration is (v - 0)/t, where t is whatever time it takes car A to come to a stop.
The car exerts this force in the direction of the wall, but the wall (which is static and unbreakable) exerts an equal force back on the car, per Newton's third law of motion. It is this equal force which causes cars to accordion up during collisions.
It is important to note that this is an idealized model. In case A, the car slams into the wall and comes to an immediate stop, which is a perfectly inelastic collision. Since the wall doesn't break or move at all, the full force of the car into the wall has to go somewhere. Either the wall is so massive that it accelerates/moves an imperceptible amount or it doesn't move at all, in which case the force of the collision actually acts on the entire planet - which is, obviously, so massive that the effects are negligible.
Force - Colliding With a Car
In case B, where car A collides with car B, we have some different force considerations. Assuming that car A and car B are complete mirrors of each other (again, this is a highly idealized situation), they would collide with each other going at precisely the same speed (but opposite directions). From conservation of momentum, we know that they must both come to rest. The mass is the same. Therefore, the force experienced by car A and car B are identical and are identical to that acting on the car in case A.
http://physics.about.com/od/energyworkpower/f/energyforcediff.htm
The cars are not mirrors of each other. So if one weights much less than the other conservation of momentum dictates it'll experience much more deceleration during a crash. There's no way around it.
Also, there is certain drawback from massive cars: the amount of energy they need to absorb in a crash against something like a tree or a bus is accordingly greater.
Quote from: Iormlund on April 14, 2009, 03:54:12 PM
Also, there is certain drawback from massive cars: the amount of energy they need to absorb in a crash against something like a tree or a bus is accordingly greater.
True, but they are generally much better built than smaller cars. Steel has a much better strength/weight ratio than unibody plastic.
Quote from: Iormlund on April 14, 2009, 03:50:33 PM
The cars are not mirrors of each other. So if one weights much less than the other conservation of momentum dictates it'll experience much more deceleration during a crash. There's no way around it.
What if one weighs more but the other has more mass?
Quote from: Iormlund on April 14, 2009, 03:50:33 PM
The cars are not mirrors of each other. So if one weights much less than the other conservation of momentum dictates it'll experience much more deceleration during a crash. There's no way around it.
I was talking about cases where they were mirrors of each other. Re-read the post you quoted when you said it was impossible.
If Kirk and mirror universe Kirk collide, what is the damage?
Quote from: Ed Anger on April 14, 2009, 04:17:34 PM
If Kirk and mirror universe Kirk collide, what is the damage?
Series gets canceled in a season and a half.
Quote from: Ed Anger on April 14, 2009, 04:17:34 PM
If Kirk and mirror universe Kirk collide, what is the damage?
Over the 4 day weekend I started growing a goatee.
I started to feel like my evil twin and shaved it off this morning.
Quote from: Neil on April 14, 2009, 03:59:14 PM
Quote from: Iormlund on April 14, 2009, 03:54:12 PM
Also, there is certain drawback from massive cars: the amount of energy they need to absorb in a crash against something like a tree or a bus is accordingly greater.
True, but they are generally much better built than smaller cars. Steel has a much better strength/weight ratio than unibody plastic.
Too strong is as bad as not enough, though. You'll die of massive internal injuries. The only part of the vehicle that doesn't have to be deformed by a crash is the driver/passenger area. Every other section has to absorb as much energy as possible.
OK; some concerns from an EMS point of view:
1) "First impact" is where the car hits. The largest and most rigid cars are the most dangerous at this point, because in this phase of the crash, the vehicle body has to crumple enough to transmit only non-lethal force to the restrained bodies in the cabin.
2) "Second impact" is actually where most life-threatening injuries occur, and is the reason the seat belt is so effective- the internal trauma is minimized because the body never gains the momentum for organs to hit the rib cage or pelvis with sufficient force to receive life-threatening damage.
My concerns about the Smart Car's safety have nothing to do with the frontside safety; we've engineered all that we can out of that. My concern is that the Smart Car is top heavy. Since virtually no traffic accidents happen in a direct line, that car could easily roll, and they've cut substantial roof support from the frame of the car.
Quote from: Barrister on April 14, 2009, 06:14:13 PMOver the 4 day weekend I started growing a goatee.
I started to feel like my evil twin and shaved it off this morning.
:(
Quote from: DontSayBanana on April 15, 2009, 07:41:18 AM
1) "First impact" is where the car hits. The largest and most rigid cars are the most dangerous at this point, because in this phase of the crash, the vehicle body has to crumple enough to transmit only non-lethal force to the restrained bodies in the cabin.
That's important, but it's even more important that there is no cabin intrusion. Look at the video where Yaris is crashed into Accord. The whole front of the car caves in on the driver.
Anybody who buys a Yaris deserves to be crushed.
Direct head-on collisions are pretty rare anyway. Most impacts are at odd angles.
Quote from: DGuller on April 15, 2009, 10:33:06 AM
Quote from: DontSayBanana on April 15, 2009, 07:41:18 AM
1) "First impact" is where the car hits. The largest and most rigid cars are the most dangerous at this point, because in this phase of the crash, the vehicle body has to crumple enough to transmit only non-lethal force to the restrained bodies in the cabin.
That's important, but it's even more important that there is no cabin intrusion. Look at the video where Yaris is crashed into Accord. The whole front of the car caves in on the driver.
Which is perfectly natural for a car going from 60 to zero mph in a crash. An Accord driver hitting a lamppost at such speeds would be just as dead. That's over twice the kinetic energy at standard 40 mph tests.
If your point is that heavier vehicles should be somehow classed as safer, then pray tell, how would you do it? You 'd need to take into account the amount of heavier or lighter vehicles in an area, the streets you'd travel on, the time of day or date and a whole lot of other variable data. That doesn't make sense at all.
That's why tests measure the capability of vehicles to withstand crashes at a set relative speed to the occupiers.
Quote from: Iormlund on April 15, 2009, 01:27:26 PM
Which is perfectly natural for a car going from 60 to zero mph in a crash. An Accord driver hitting a lamppost at such speeds would be just as dead. That's over twice the kinetic energy at standard 40 mph tests.
Where did you get the 60 mph figure? The cars were going at 40 mph in tests.
QuoteIf your point is that heavier vehicles should be somehow classed as safer, then pray tell, how would you do it?
Crash them head on against a standard vehicle size. Don't crash small cars against small cars, and big cars against big cars (that's not what is really being done, but that's the equivalent of crashing cars into immovable barriers).
Quote from: DGuller on April 15, 2009, 02:07:52 PM
Quote from: Iormlund on April 15, 2009, 01:27:26 PM
Which is perfectly natural for a car going from 60 to zero mph in a crash. An Accord driver hitting a lamppost at such speeds would be just as dead. That's over twice the kinetic energy at standard 40 mph tests.
Where did you get the 60 mph figure? The cars were going at 40 mph in tests.
It's a guess, but if you're really curious you can calculate it by way of the conservation of momentum.
Quote
QuoteIf your point is that heavier vehicles should be somehow classed as safer, then pray tell, how would you do it?
Crash them head on against a standard vehicle size. Don't crash small cars against small cars, and big cars against big cars (that's not what is really being done, but that's the equivalent of crashing cars into immovable barriers).
But that's not giving you a complete picture either. Frontal crashes against other vehicles are hardly the norm. Even worse, it would lead to heavier, unsafer cars as the manufacturers opt out of using expensive electronic and mechanic devices in favor of installing heavier engines or whatever. The one thing that's made safety as good as it is today is that it's a frenetic race to get those perfect scores in NCAP tests.
Quote from: Iormlund on April 15, 2009, 04:04:14 PM
But that's not giving you a complete picture either. Frontal crashes against other vehicles are hardly the norm.
Who's saying that this should be the only test? There are many types of crashes, and many types of tests. Head-ons are pretty rare, but very deadly when they happen, and in US they account for 10% of fatalities. It would be useful to have a reliable safety rating associated with it, especially if you're living in an area where head-ons are more likely (rural area with two-lane roads, for example).
San Francisco is full of two lane roads without dividers. (Although many of the larger multi-lane roads have them.)