CAFE Standards Kill 2000 per Year

Off Topic
41

Hi,

I’m not sure who you were addressing your response to, but you and I agree. :slight_smile:

[quote]tom63 wrote:
Damici wrote:
I’m not saying that it’s the weight IN AND OF ITSELF that causes the larger vehicle to be safer in a given crash situation (like hitting a tree, in this example). It’s ALL THE FACTORS THAT CONTRIBUTE TO MAKING IT A SAFER CAR (which I listed) that make it safer – and those things all CAUSE THE CAR TO BE HEAVIER. (Much sturdier passenger safety cage with more metal in it; longer front end, which entails more metal; bigger, longer, more spacious passenger compartment, which entails more metal . . . ). It’s not the weight itself that makes it safer – it’s all the things I mentioned – (which happen to make it weigh a lot) – which make it safer.

The bottom line remains:

You’re much better off hitting a tree at 45 mph in a Mercedes S600 than you are doing the same thing in a Mini Cooper.

And yes, or course, if the two were to hit each other, it’s a given, as you mentioned, that the person in the bigger car is better off.

Carnak wrote:
Damici wrote:
No offense to you either, but you’re completely misunderstanding how the physics work in this particular situation. Assuming they hit the tree at at the same rate, traveling at a steady state of, say, 45 mph, the passengers in the Benz are far better off for a number of reasons, all of which contribute to that car being heavier, for better or worse:

More size (longer front end and larger passenger compartment in particular), which indeed provides a larger crumple zone which can absorb the impact, as well as more space in the interior of the car between passengers and the dashboard, or between rear seat passengers and the seat in front of them; more overall mass (steel etc.) in the frame, chassis and engine of the vehicle, which past a certain speed (beyond which the crumple zones have already done their job) prevents the passenger compartment from being crushed like it would be in the Mini; a stronger, stiffer, heavier “safety cage” around the passenger compartment than the Mini has, due in part to just a lot more metal being used to form it.

If you honestly mean to tell me that you’d rather be in a freaking MINI when you hit that tree at 45 mph versus a MERCEDES S600, then you, my friend, have serious judgement issues.

No, what I’m telling you is that size/weight does not necessarily equate to safety. Also, you are confusing a vehicle vs vehicle collision with vehicle vs stationary object (tree or concrete barrier). In a vehicle vs. vehicle collision, it will most likely be “safer” to be in the larger vehicle, largely because of its larger mass. It’s all about momentum. The heavier vehicle traveling at the same speed will have a lot more momentum than the smaller one and will transfer more force onto the smaller vehicle when they impact than the smaller vehicle will to the larger. Then you take in their safety ratios and force transfer ratings and you get an idea of how injured people might be.

When hitting a stationary object, it will LIKELY be safer to be in the smaller car, due to less force being involved in the collision. It is not necessarily so, due to different safety ratings in the vehicles. It also wouldn’t be so if the vehicle has much more kinetic energy than the potential energy of the thing it’s hitting. A semi could plow through a barrier and the driver would be alright whereas somebody in a civic might be fucked (assuming very high speeds).

Anyways, it’s silly to argue large vs small. I’ll take the vehicle with the best ratings. I used to own a Saab and I’d get another one. There’s a small, heavy car with wonderful safety ratings. It’s an engineering problem, not a size one. Same thing with fuel economy standards.

The really ironic thing is it’s always “safer” to be the person hitting someone else. Cars have the most safety features if they get hit in the front. Hence all the tragic accidents where somebody gets t-boned and killed by some careless (or maybe drunk) asshole, and the asshole doesn’t have a scratch.

You’re wrong about hitting the inanimate object. The bigger vehicle always wins, because of the greater amount of metal a stated previously. It’s bigger for a reason. The weight added isn’t just extra weight for it’s own sake, but greater reinforcing and so on.

As for the odds likely I’ll get hit by a smaller vehicle, you can’t use statistics for a general population and then use them for a sample size of me. It doesn’t work, since the amount of collisions I’ll have is hopefully no more.

The odds are 100% yes or no for me, not 75%, 22%, or so on.

[/quote]

42

[quote]Damici wrote:
I’m not saying that it’s the weight IN AND OF ITSELF that causes the larger vehicle to be safer in a given crash situation (like hitting a tree, in this example). It’s ALL THE FACTORS THAT CONTRIBUTE TO MAKING IT A SAFER CAR (which I listed) that make it safer – and those things all CAUSE THE CAR TO BE HEAVIER. (Much sturdier passenger safety cage with more metal in it; longer front end, which entails more metal; bigger, longer, more spacious passenger compartment, which entails more metal . . . ). It’s not the weight itself that makes it safer – it’s all the things I mentioned – (which happen to make it weigh a lot) – which make it safer.

The bottom line remains:

You’re much better off hitting a tree at 45 mph in a Mercedes S600 than you are doing the same thing in a Mini Cooper.

And yes, or course, if the two were to hit each other, it’s a given, as you mentioned, that the person in the bigger car is better off.

[/quote]

Here is where we disagree: Your assumption is that the extra weight of a larger car directly correlates to safety or safety features. If you drop that assumption we can get along, because after that we’re basically saying the same thing - that safety features are the biggest factor.

You gonna tell me that the bigger drive train & axles on a V8 somehow is part of its safety feature? What about all the weight of the frame that isn’t in the area of where the collision takes place on the car? Yes, bigger, stronger steel will absorb more impact. The part that you continue to ignore, is that the greater weight of all the rest of the vehicle generates more momentum and creates more force, aka, a bigger impact, and partially negates the greater strength of that steel. You see my point yet?

A 2-ton SUV and a 1/2 ton mini hit a concrete barrier at 30mph at the same time. Assume the concrete barrier absorbs the entire impact and the vehicles stop in a fraction of a second (let’s call it 1/2 second).

F = ma; a = v/t

(1 mi/hr)(1 hour/3,600 sec)(1.61 km/1 mile)*(1000 meters/1 km) = 0.45 m/s

30 * .45 m/s = 13.5 m/s

a = (13.5 m/s) / (.5 s) = 27 m/s^2

m1 = 4000 pounds * (.454 kg/pound) = 1816kg
m2 = 1000 pounds * (.454 kg/pound) = 454kg

F1 = m1a = 1816kg * 27 m/s^2 = 49032 N
F2 = m2a = 454kg * 27 m/s^2 = 12258 N

Now assume both vehicles have equal safety ratings and absorb 99% of force on a frontal impact.

F1 (transferred) = 49032N *.01 = 490.32N
F2 (transferred) = 12258N *.01 = 122.58N

If the cars are equally safe, the rider in the heavier car absorbs more force of impact than the rider in the smaller car as a ratio of their difference in mass.

43

We all (hopefully) understand the basic F=MA premise, and how everything derives from that. All makes sense UNTIL you get to the part where you mention “assume both vehicles have equal safety ratings.” Therein lies the difference.

I’m not sure what “safety ratings” you’re referring to, but if you’re talking about the general magazine or insurance industry type ratings where they’ll give cars in each size category a “5-star” or “4-star” or “excellent” or “good” rating . . . well that isn’t really defined in a numerically quantifiable way. And just as importantly, for a car to get a “5-star” or “top” rating for front-end collision protection in the subcompact category does NOT mean that the passengers will fare as well as they would in a car that got a “5-star” or “top” rating in the full-size/premium sedan category! So “assuming they both have equal safety ratings” is what skews the whole assumption.

The big Benz hits with more decelerating force because it weighs more, yes. However, it also more than overcomes the fact that it hits with additional force, and manages to protects its occupants far better because . . . . of the factors that make it weigh more! Aaaaaall that additional steel in the passenger safety compartment, all that additional steel (and length) in the front end/engine compartment of the car, all that additional space between occupants’ bodies (and legs) and the dashboard (or seat in front of them) combine to equal . . . the occupants of the S600 faring far better in that same crash with an immobile object than the occupants of the Mini.

Again, I ask you in all seriousness: If you had a choice right now to strap into either car, the S600 or the Mini, and drive head-on into a tree at 45 mph, can you HONESTLY tell me you’d prefer to do so in the Mini?

We all know that no sane, sober, right-thinking person would choose the Mini in that case. The reason why is explained above.

[quote]Carnak wrote:
Damici wrote:
I’m not saying that it’s the weight IN AND OF ITSELF that causes the larger vehicle to be safer in a given crash situation (like hitting a tree, in this example). It’s ALL THE FACTORS THAT CONTRIBUTE TO MAKING IT A SAFER CAR (which I listed) that make it safer – and those things all CAUSE THE CAR TO BE HEAVIER. (Much sturdier passenger safety cage with more metal in it; longer front end, which entails more metal; bigger, longer, more spacious passenger compartment, which entails more metal . . . ). It’s not the weight itself that makes it safer – it’s all the things I mentioned – (which happen to make it weigh a lot) – which make it safer.

The bottom line remains:

You’re much better off hitting a tree at 45 mph in a Mercedes S600 than you are doing the same thing in a Mini Cooper.

And yes, or course, if the two were to hit each other, it’s a given, as you mentioned, that the person in the bigger car is better off.

Here is where we disagree: Your assumption is that the extra weight of a larger car directly correlates to safety or safety features. If you drop that assumption we can get along, because after that we’re basically saying the same thing - that safety features are the biggest factor.

You gonna tell me that the bigger drive train & axles on a V8 somehow is part of its safety feature? What about all the weight of the frame that isn’t in the area of where the collision takes place on the car? Yes, bigger, stronger steel will absorb more impact. The part that you continue to ignore, is that the greater weight of all the rest of the vehicle generates more momentum and creates more force, aka, a bigger impact, and partially negates the greater strength of that steel. You see my point yet?

A 2-ton SUV and a 1/2 ton mini hit a concrete barrier at 30mph at the same time. Assume the concrete barrier absorbs the entire impact and the vehicles stop in a fraction of a second (let’s call it 1/2 second).

F = ma; a = v/t

(1 mi/hr)(1 hour/3,600 sec)(1.61 km/1 mile)*(1000 meters/1 km) = 0.45 m/s

30 * .45 m/s = 13.5 m/s

a = (13.5 m/s) / (.5 s) = 27 m/s^2

m1 = 4000 pounds * (.454 kg/pound) = 1816kg
m2 = 1000 pounds * (.454 kg/pound) = 454kg

F1 = m1a = 1816kg * 27 m/s^2 = 49032 N
F2 = m2a = 454kg * 27 m/s^2 = 12258 N

Now assume both vehicles have equal safety ratings and absorb 99% of force on a frontal impact.

F1 (transferred) = 49032N *.01 = 490.32N
F2 (transferred) = 12258N *.01 = 122.58N

If the cars are equally safe, the rider in the heavier car absorbs more force of impact than the rider in the smaller car as a ratio of their difference in mass.[/quote]

44

Hell no man, I’d take the Benz. I think we all agree on the basic idea that you should go with a car/truck whatever that fits your needs and has an acceptable safety threshold. The rest is kinda rhetorical, but physics is fun.

Another thing about the statistics I’m wondering about is the number of people in fatal accidents who weren’t wearing seatbelts. SUVs tend to roll more, and there are more fatalities there per accident. Could this be a simple result that someone not wearing a seatbelt is more likely to die in an accident if their car rolls over (and they smash their head)?

45

Another thing I wonder about is driver profile with regard to different types of vehicles – I’m not sure if that was taken into account in any of these studies.

Do people who drive SUVs, on average, tend to be cockier, more reckless types, or people who tend to drive faster in general, especially in rain or snow because they think they’ll be just fine in their big 4WD SUV? I know it was noted that sports car drivers on average drive faster and perhaps more recklessly. I wonder about SUV drivers.

46

[quote]Damici wrote:

Again, I ask you in all seriousness: If you had a choice right now to strap into either car, the S600 or the Mini, and drive head-on into a tree at 45 mph, can you HONESTLY tell me you’d prefer to do so in the Mini?

[/quote]

The question is only relevant for a short time: only Al Gore and all his cronies will get to drive cars like that. We’ll be on busses or in little bubble cars that pop if you touch 'em.

It’s all the carbon footprint, you know.

47

Yep, I definitely agree with you. Every bit of classwork I saw does also.

[quote]Damici wrote:
Hi,

I’m not sure who you were addressing your response to, but you and I agree. :slight_smile:

tom63 wrote:
Damici wrote:
I’m not saying that it’s the weight IN AND OF ITSELF that causes the larger vehicle to be safer in a given crash situation (like hitting a tree, in this example). It’s ALL THE FACTORS THAT CONTRIBUTE TO MAKING IT A SAFER CAR (which I listed) that make it safer – and those things all CAUSE THE CAR TO BE HEAVIER. (Much sturdier passenger safety cage with more metal in it; longer front end, which entails more metal; bigger, longer, more spacious passenger compartment, which entails more metal . . . ). It’s not the weight itself that makes it safer – it’s all the things I mentioned – (which happen to make it weigh a lot) – which make it safer.

The bottom line remains:

You’re much better off hitting a tree at 45 mph in a Mercedes S600 than you are doing the same thing in a Mini Cooper.

And yes, or course, if the two were to hit each other, it’s a given, as you mentioned, that the person in the bigger car is better off.

Carnak wrote:
Damici wrote:
No offense to you either, but you’re completely misunderstanding how the physics work in this particular situation. Assuming they hit the tree at at the same rate, traveling at a steady state of, say, 45 mph, the passengers in the Benz are far better off for a number of reasons, all of which contribute to that car being heavier, for better or worse:

More size (longer front end and larger passenger compartment in particular), which indeed provides a larger crumple zone which can absorb the impact, as well as more space in the interior of the car between passengers and the dashboard, or between rear seat passengers and the seat in front of them; more overall mass (steel etc.) in the frame, chassis and engine of the vehicle, which past a certain speed (beyond which the crumple zones have already done their job) prevents the passenger compartment from being crushed like it would be in the Mini; a stronger, stiffer, heavier “safety cage” around the passenger compartment than the Mini has, due in part to just a lot more metal being used to form it.

If you honestly mean to tell me that you’d rather be in a freaking MINI when you hit that tree at 45 mph versus a MERCEDES S600, then you, my friend, have serious judgement issues.

No, what I’m telling you is that size/weight does not necessarily equate to safety. Also, you are confusing a vehicle vs vehicle collision with vehicle vs stationary object (tree or concrete barrier). In a vehicle vs. vehicle collision, it will most likely be “safer” to be in the larger vehicle, largely because of its larger mass. It’s all about momentum. The heavier vehicle traveling at the same speed will have a lot more momentum than the smaller one and will transfer more force onto the smaller vehicle when they impact than the smaller vehicle will to the larger. Then you take in their safety ratios and force transfer ratings and you get an idea of how injured people might be.

When hitting a stationary object, it will LIKELY be safer to be in the smaller car, due to less force being involved in the collision. It is not necessarily so, due to different safety ratings in the vehicles. It also wouldn’t be so if the vehicle has much more kinetic energy than the potential energy of the thing it’s hitting. A semi could plow through a barrier and the driver would be alright whereas somebody in a civic might be fucked (assuming very high speeds).

Anyways, it’s silly to argue large vs small. I’ll take the vehicle with the best ratings. I used to own a Saab and I’d get another one. There’s a small, heavy car with wonderful safety ratings. It’s an engineering problem, not a size one. Same thing with fuel economy standards.

The really ironic thing is it’s always “safer” to be the person hitting someone else. Cars have the most safety features if they get hit in the front. Hence all the tragic accidents where somebody gets t-boned and killed by some careless (or maybe drunk) asshole, and the asshole doesn’t have a scratch.

You’re wrong about hitting the inanimate object. The bigger vehicle always wins, because of the greater amount of metal a stated previously. It’s bigger for a reason. The weight added isn’t just extra weight for it’s own sake, but greater reinforcing and so on.

As for the odds likely I’ll get hit by a smaller vehicle, you can’t use statistics for a general population and then use them for a sample size of me. It doesn’t work, since the amount of collisions I’ll have is hopefully no more.

The odds are 100% yes or no for me, not 75%, 22%, or so on.

[/quote]

48

[quote]Damici wrote:
Another thing I wonder about is driver profile with regard to different types of vehicles – I’m not sure if that was taken into account in any of these studies.

Do people who drive SUVs, on average, tend to be cockier, more reckless types, or people who tend to drive faster in general, especially in rain or snow because they think they’ll be just fine in their big 4WD SUV? I know it was noted that sports car drivers on average drive faster and perhaps more recklessly. I wonder about SUV drivers.[/quote]

Personally, I think it’s clueless teenagers and women who drive SUVs like little miatas who are the culprit. People who are normal truck type drivers understand the higher center of gravity thing.

49

Exactly, there are many factors that come into play, and seatbelts are on of them.

Stats are like slutty women, when you get a hold of them, you can do whatever you want with them.

[quote]Carnak wrote:
Hell no man, I’d take the Benz. I think we all agree on the basic idea that you should go with a car/truck whatever that fits your needs and has an acceptable safety threshold. The rest is kinda rhetorical, but physics is fun.

Another thing about the statistics I’m wondering about is the number of people in fatal accidents who weren’t wearing seatbelts. SUVs tend to roll more, and there are more fatalities there per accident. Could this be a simple result that someone not wearing a seatbelt is more likely to die in an accident if their car rolls over (and they smash their head)?[/quote]

50

[quote]Carnak wrote:
Damici wrote:
I’m not saying that it’s the weight IN AND OF ITSELF that causes the larger vehicle to be safer in a given crash situation (like hitting a tree, in this example). It’s ALL THE FACTORS THAT CONTRIBUTE TO MAKING IT A SAFER CAR (which I listed) that make it safer – and those things all CAUSE THE CAR TO BE HEAVIER. (Much sturdier passenger safety cage with more metal in it; longer front end, which entails more metal; bigger, longer, more spacious passenger compartment, which entails more metal . . . ). It’s not the weight itself that makes it safer – it’s all the things I mentioned – (which happen to make it weigh a lot) – which make it safer.

The bottom line remains:

You’re much better off hitting a tree at 45 mph in a Mercedes S600 than you are doing the same thing in a Mini Cooper.

And yes, or course, if the two were to hit each other, it’s a given, as you mentioned, that the person in the bigger car is better off.

Here is where we disagree: Your assumption is that the extra weight of a larger car directly correlates to safety or safety features. If you drop that assumption we can get along, because after that we’re basically saying the same thing - that safety features are the biggest factor.

You gonna tell me that the bigger drive train & axles on a V8 somehow is part of its safety feature? What about all the weight of the frame that isn’t in the area of where the collision takes place on the car? Yes, bigger, stronger steel will absorb more impact. The part that you continue to ignore, is that the greater weight of all the rest of the vehicle generates more momentum and creates more force, aka, a bigger impact, and partially negates the greater strength of that steel. You see my point yet?

A 2-ton SUV and a 1/2 ton mini hit a concrete barrier at 30mph at the same time. Assume the concrete barrier absorbs the entire impact and the vehicles stop in a fraction of a second (let’s call it 1/2 second).

F = ma; a = v/t

(1 mi/hr)(1 hour/3,600 sec)(1.61 km/1 mile)*(1000 meters/1 km) = 0.45 m/s

30 * .45 m/s = 13.5 m/s

a = (13.5 m/s) / (.5 s) = 27 m/s^2

m1 = 4000 pounds * (.454 kg/pound) = 1816kg
m2 = 1000 pounds * (.454 kg/pound) = 454kg

F1 = m1a = 1816kg * 27 m/s^2 = 49032 N
F2 = m2a = 454kg * 27 m/s^2 = 12258 N

Now assume both vehicles have equal safety ratings and absorb 99% of force on a frontal impact.

F1 (transferred) = 49032N *.01 = 490.32N
F2 (transferred) = 12258N *.01 = 122.58N

If the cars are equally safe, the rider in the heavier car absorbs more force of impact than the rider in the smaller car as a ratio of their difference in mass.[/quote]

There is some sort of maybe truth here. A crash test rates the car hitting a car the same size and weight as itself. But there can be some differences in the vehicles that make one safer over the other.

So the mini might actually be designed better than the pickup and do better if the SUV or pick up is designed crappy wise. But
the drive train and other stuff will help take up the crush better overall.

It would be good to see the safety ratings of each vehicle. Honda, Volvo, and Mercedes has always done well safety wise. Subaru also does.