NHTSA says "Don't make small vehicles lighter"!
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NHTSA says "Don't make small vehicles lighter"!
National Highway Traffic Safety Administration (NHTSA) says "Don't make small vehicles lighter"!
http://www.autonews.com/news.cms?newsId=6683
quote:
“Cutting vehicle weights across the board would make vehicles even more unsafe than previously thought. But reducing the weights of the larger light trucks on the roads would have little effect and could lead to fewer highway deaths overall.
These are key conclusions of a highly anticipated federal study of the safety effects of reducing vehicle weights. Made public Tuesday, it updates a 1997 study, also by the National Highway Traffic Safety Administration. And it is certain to be fodder for upcoming debates about how to change corporate average fuel economy standards, or CAFE, after the 2007 model year. CAFE rules are set until then. “
http://www.autonews.com/news.cms?newsId=6683
quote:
“Cutting vehicle weights across the board would make vehicles even more unsafe than previously thought. But reducing the weights of the larger light trucks on the roads would have little effect and could lead to fewer highway deaths overall.
These are key conclusions of a highly anticipated federal study of the safety effects of reducing vehicle weights. Made public Tuesday, it updates a 1997 study, also by the National Highway Traffic Safety Administration. And it is certain to be fodder for upcoming debates about how to change corporate average fuel economy standards, or CAFE, after the 2007 model year. CAFE rules are set until then. “
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It's nice to see that the Federal Government finally caught up with Newtonian physics....
FORCE = mass*acceleration
ENERGY = 1/2*velocity^2
My only hope now is that they finally realize the world is a sphere and not flat.
FORCE = mass*acceleration
ENERGY = 1/2*velocity^2
My only hope now is that they finally realize the world is a sphere and not flat.
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Re: NHTSA says "Don't make small vehicles lighter"!
Originally posted by johnsocal
But reducing the weights of the larger light trucks on the roads would have little effect and could lead to fewer highway deaths overall.
But reducing the weights of the larger light trucks on the roads would have little effect and could lead to fewer highway deaths overall.
Maybe we should all stop being afraid of the soccer mom in the Suburban.
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From: The Golden State
This is what helped the Clinton administration keep the safety nuts at bay when they were pushing for higher CAFE standards about 6 years ago, before they turned attention to SUVs.
Government is generally neutral. Unfortunately it's the very loud very small fringe group of people that stir up the pot. Sometimes for great things, but not here.
Government is generally neutral. Unfortunately it's the very loud very small fringe group of people that stir up the pot. Sometimes for great things, but not here.
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From: Ontario
The first point they're missing is the effect of mass on the handling and braking of a vehicle. All things being equal, a heavier vehicle will not stop as fast nor be as nimble as a lighter vehicle. Therefore, by advocating heavier vehicles, they are increasing the chance that a given vehicle will be in an accident.
The second point is that weight is relative. If every vehicle weighs 6000 lbs then it's a draw. It's kind of like standing out of your seat at a baseball game: you only get a better view until everyone else does it too, then you're all equal again. On a moral level, I find it to be a very selfish decision when someone buys 6000 lb vehicle thinking it's "safer", because their extra safety is completely at the expense of whoever they hit. Add that to the increased chance they have of hitting something, and buying heavy vehicles becomes an increasingly irresponsible decision.
You know, I think a good lawyer using that reasoning could have some luck suing SUV drivers that are involved in accidents:
Lawyer: "Ms Jones, why did you buy that Excursion"
Ms. Jones: "Because it was safe"
Lawyer: "Why is it safe"
Ms. Jones: "Because it is so big"
Laywer: "Do you know anything about physics, Ms. Jones ...."
The second point is that weight is relative. If every vehicle weighs 6000 lbs then it's a draw. It's kind of like standing out of your seat at a baseball game: you only get a better view until everyone else does it too, then you're all equal again. On a moral level, I find it to be a very selfish decision when someone buys 6000 lb vehicle thinking it's "safer", because their extra safety is completely at the expense of whoever they hit. Add that to the increased chance they have of hitting something, and buying heavy vehicles becomes an increasingly irresponsible decision.
You know, I think a good lawyer using that reasoning could have some luck suing SUV drivers that are involved in accidents:
Lawyer: "Ms Jones, why did you buy that Excursion"
Ms. Jones: "Because it was safe"
Lawyer: "Why is it safe"
Ms. Jones: "Because it is so big"
Laywer: "Do you know anything about physics, Ms. Jones ...."
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Originally posted by R377
The first point they're missing is the effect of mass on the handling and braking of a vehicle. All things being equal, a heavier vehicle will not stop as fast nor be as nimble as a lighter vehicle. Therefore, by advocating heavier vehicles, they are increasing the chance that a given vehicle will be in an accident.
The first point they're missing is the effect of mass on the handling and braking of a vehicle. All things being equal, a heavier vehicle will not stop as fast nor be as nimble as a lighter vehicle. Therefore, by advocating heavier vehicles, they are increasing the chance that a given vehicle will be in an accident.
Year in and year out, the safest vehicles in deaths per 1,000,000 miles driven are large, heavy sedans.... not nimble little sports cars.
Originally posted by R377
On a moral level, I find it to be a very selfish decision when someone buys 6000 lb vehicle thinking it's "safer", because their extra safety is completely at the expense of whoever they hit.
On a moral level, I find it to be a very selfish decision when someone buys 6000 lb vehicle thinking it's "safer", because their extra safety is completely at the expense of whoever they hit.
Second, larger vehicles are not only safer in 2 (or more...) vehicle accidents, but they are also safer in accidents that involve hitting things other than other vehicles.
Third, if you buy a little car because you want the rest of the world to be safer, I feel no responsibity whatsoever if I accidentally run your a$$ over with a K3500 Diesel. You made a choice, and it was a dumb one at that.
Fourth, my primary responsibility in this life is to health, safety and welfare of my family. Yours is to your family. I'll handle mine, you take care of yours. I would invite you not to compromise their safety on a set of fatally flawed assumptions.
Originally posted by R377
Add that to the increased chance they have of hitting something, and buying heavy vehicles becomes an increasingly irresponsible decision.
Add that to the increased chance they have of hitting something, and buying heavy vehicles becomes an increasingly irresponsible decision.
I'm not responsible for you. If you buy a Yugo and get killed in an accident with a 1959 Cadillac Eldorado, I call that natural selection.
Originally posted by R377
You know, I think a good lawyer using that reasoning could have some luck suing SUV drivers that are involved in accidents:
Lawyer: "Ms Jones, why did you buy that Excursion"
Ms. Jones: "Because it was safe"
Lawyer: "Why is it safe"
Ms. Jones: "Because it is so big"
Laywer: "Do you know anything about physics, Ms. Jones ...."
You know, I think a good lawyer using that reasoning could have some luck suing SUV drivers that are involved in accidents:
Lawyer: "Ms Jones, why did you buy that Excursion"
Ms. Jones: "Because it was safe"
Lawyer: "Why is it safe"
Ms. Jones: "Because it is so big"
Laywer: "Do you know anything about physics, Ms. Jones ...."
Ms. Jones is right, Newton says so, Einstein says so, and so does everyone who knows anything about vehicle engineering.
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Joined: Aug 2002
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From: Houston, TX
Pacer,
I would like to respectfully say that you missed his point. If you are driving a K3500 diesel and you hit me while i am driving a k3500 Diesel then the weight issue has nothing do with safety. You are only safer in you K3500 if you hit a Yugo. Thats what he meant by making yourself safer at the expense of others.
Chris
I would like to respectfully say that you missed his point. If you are driving a K3500 diesel and you hit me while i am driving a k3500 Diesel then the weight issue has nothing do with safety. You are only safer in you K3500 if you hit a Yugo. Thats what he meant by making yourself safer at the expense of others.
Chris
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Nope, I got his point, it's just wrong.
Let's take two K3500 diesels and smash them into each other at 30 mph. Given the equation Energy = 1/2*mass*velocity^2, we very quickly see that due to the fact that velocity is the squared component and the effect of mass is halved, impact energy goes up radically for velocity, but not too much for mass.
Now, here's a simple rule of thumb for a body...
For any body with a given frontal area, an increase in one component of frontal area increases volume BY THE SQUARE of the value changed. Like this:
10*10*10=1000, 11*10*10=1100 (1100-1000=100, which equals 10^2)
50*50*50=125,000, 51*50*50=127,500 (127,500-125,000=2500, which equals 50^2)
Did you follow that?
The best approximation for crush area in a car (we're using rules of thumb here to keep things simple) is the volume of that area up front. The bigger vehicle has, by definition, more impact area. Greater impact area = more volume to crush, which means more energy can be traded off for deformation in an impact.
Now... follow this...
Two K3500's crashing into each other have VASTLY more volume to crush than two Cavaliers do. The only trade-off against that is the actual amount of energy to be dissipated within that volume, which only went up by a factor of 1/2 (1/2*mass in the energy equation).
This also indicates a very basic problem with the insurance industry using an offset frontal crash to validate vehicle safety:
To do well in an offset frontal crash, you have to stiffen the area that is going to be impacted. When you do that, you automatically bias the vehicle against doing as well in the Federal Government's full frontal crash testing. The two specifications fight each other. To make one better, I sacrifice performance in the other.
GM's tack has been to do well in the Federal Testing to the detriment of the insurance testing. Toyota has generally done the opposite.
To sum up:
Larger, heavier vehicles are inherently safer than small, light vehicles simply due to the fact that they are larger and heavier.
Let's take two K3500 diesels and smash them into each other at 30 mph. Given the equation Energy = 1/2*mass*velocity^2, we very quickly see that due to the fact that velocity is the squared component and the effect of mass is halved, impact energy goes up radically for velocity, but not too much for mass.
Now, here's a simple rule of thumb for a body...
For any body with a given frontal area, an increase in one component of frontal area increases volume BY THE SQUARE of the value changed. Like this:
10*10*10=1000, 11*10*10=1100 (1100-1000=100, which equals 10^2)
50*50*50=125,000, 51*50*50=127,500 (127,500-125,000=2500, which equals 50^2)
Did you follow that?
The best approximation for crush area in a car (we're using rules of thumb here to keep things simple) is the volume of that area up front. The bigger vehicle has, by definition, more impact area. Greater impact area = more volume to crush, which means more energy can be traded off for deformation in an impact.
Now... follow this...
Two K3500's crashing into each other have VASTLY more volume to crush than two Cavaliers do. The only trade-off against that is the actual amount of energy to be dissipated within that volume, which only went up by a factor of 1/2 (1/2*mass in the energy equation).
This also indicates a very basic problem with the insurance industry using an offset frontal crash to validate vehicle safety:
To do well in an offset frontal crash, you have to stiffen the area that is going to be impacted. When you do that, you automatically bias the vehicle against doing as well in the Federal Government's full frontal crash testing. The two specifications fight each other. To make one better, I sacrifice performance in the other.
GM's tack has been to do well in the Federal Testing to the detriment of the insurance testing. Toyota has generally done the opposite.
To sum up:
Larger, heavier vehicles are inherently safer than small, light vehicles simply due to the fact that they are larger and heavier.
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Joined: Mar 2001
Posts: 13,713
From: The Golden State
Something interesting (sort of follows what Pacer was saying):
http://www.detnews.com/2003/autosins...b01-298332.htm
The article covers the same story, but is a bit more detailed.
"Large four-door passenger cars had the lowest death rates, followed closely by minivans. Small, four-door cars had the highest fatality rates, with mid-size SUVs and compact pickups second.
In certain types of crashes, pickups and SUVs are equal to or better than cars in terms of safety. But the possibility of a rollover crash makes an SUV more dangerous overall than a similarly-sized car.
NHTSA found that mid-size SUVs weighing on average 4,022 pounds are nine times as likely to roll over than large cars weighing 3,596 pounds, and were twice as likely to kill an occupant of another vehicle. "
In certain types of crashes, pickups and SUVs are equal to or better than cars in terms of safety. But the possibility of a rollover crash makes an SUV more dangerous overall than a similarly-sized car.
NHTSA found that mid-size SUVs weighing on average 4,022 pounds are nine times as likely to roll over than large cars weighing 3,596 pounds, and were twice as likely to kill an occupant of another vehicle. "
The article covers the same story, but is a bit more detailed.
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Joined: Nov 2000
Posts: 2,712
From: Ontario
Originally posted by PacerX
This is wrong.
Year in and year out, the safest vehicles in deaths per 1,000,000 miles driven are large, heavy sedans.... not nimble little sports cars.
This is wrong.
Year in and year out, the safest vehicles in deaths per 1,000,000 miles driven are large, heavy sedans.... not nimble little sports cars.
Also you need to factor in driving habits when touting accident statistics because we all know drivers of sports cars are more reckless than soccer moms in Caravans, and that has nothing to do with the capabilites of the vehicle itself.
Originally posted by PacerX
First, keep your morality out of my garage, especially when it flies in the face of easily deduced physical facts.
Second, larger vehicles are not only safer in 2 (or more...) vehicle accidents, but they are also safer in accidents that involve hitting things other than other vehicles.
First, keep your morality out of my garage, especially when it flies in the face of easily deduced physical facts.
Second, larger vehicles are not only safer in 2 (or more...) vehicle accidents, but they are also safer in accidents that involve hitting things other than other vehicles.
Originally posted by PacerX
Third, if you buy a little car because you want the rest of the world to be safer, I feel no responsibity whatsoever if I accidentally run your a$$ over with a K3500 Diesel. You made a choice, and it was a dumb one at that.
Fourth, my primary responsibility in this life is to health, safety and welfare of my family. Yours is to your family. I'll handle mine, you take care of yours. I would invite you not to compromise their safety on a set of fatally flawed assumptions.
Third, if you buy a little car because you want the rest of the world to be safer, I feel no responsibity whatsoever if I accidentally run your a$$ over with a K3500 Diesel. You made a choice, and it was a dumb one at that.
Fourth, my primary responsibility in this life is to health, safety and welfare of my family. Yours is to your family. I'll handle mine, you take care of yours. I would invite you not to compromise their safety on a set of fatally flawed assumptions.
? We're talking theory here, okay? I have no desire to get into one of your pissing matches.But on your fourth point. I will say it's an incredibly selfish stance when a person puts their own good above everyone else's, especially for little reason. Most societies have advanced a little beyond that.
Originally posted by PacerX
And I will be happy to be the expert rebuttal witness who will re-educate this misguided liberal arts major attorney relative to impact physics.
Ms. Jones is right, Newton says so, Einstein says so, and so does everyone who knows anything about vehicle engineering.
And I will be happy to be the expert rebuttal witness who will re-educate this misguided liberal arts major attorney relative to impact physics.
Ms. Jones is right, Newton says so, Einstein says so, and so does everyone who knows anything about vehicle engineering.
Again, I'm not saying she's wrong when she thinks she's more likely to survive an accident. But what I am saying is she made a conscious choice to do something for no other reason than to increase the chance of harming someone else versus her own perception of safety.
Buy hey, it was a tongue-in-cheek comment and I'm no lawyer (and certainly not a liberal arts major). I just thought it was an interesting possibility. Maybe we'll see it on an NBC movie of the week.
FWIW, I'm not in any way advocating limiting people's choice of vehicles. If you need a F350 because you haul horses then that makes sense. I'm just saying people who buy the biggest thing out there just because they think it's safe, well there's flawed reasoning and questionable ethics behind their choice.
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Joined: Jun 2001
Posts: 4,600
From: Pewee Valley, KY
Originally posted by R377
...
Again, I'm not saying she's wrong when she thinks she's more likely to survive an accident. But what I am saying is she made a conscious choice to do something for no other reason than to increase the chance of harming someone else versus her own perception of safety...
...
Again, I'm not saying she's wrong when she thinks she's more likely to survive an accident. But what I am saying is she made a conscious choice to do something for no other reason than to increase the chance of harming someone else versus her own perception of safety...
