Safety: Does size of car matter as long as it has 5star crash rating?

[JEDI]

i always imagine that if the Smart gets hit by a truck, it'll go off like a pinball bouncing all over the place.

But if a small car has a 5star crash rating in every categotry, does its size matter?

 

[JulesMaximus]

I think everyone should drive a Ford Excursion. That way we would all be safe and nobody would ever get hurt in accidents.

BAN ALL SMALL CARS!!!

 

[iamwiz82]

Crash test ratings are only comparable among similarly sized vehicles.

 

[angry hampster]

SUVS ROLL OVER EVERY MOMENT

 

[Jumpem]

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

This. Which I think is stupid. It doesn't let people easily compare safety ratings between vehicles of different sgements.

 

[Strk]

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

The side-impact test isn't.

Besides the inherent problems with crash tests, the size does matter. Even if the cage (passenger area, whatever you want to call it) is indestructible, the larger vehicle will always be safer. One of the major things the extra space gets you is more that has to be crushed before the vehicle stops. That means less of a shock to your system.

 

[thomsbrain]

Originally posted by: Strk

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

The side-impact test isn't.

Besides the inherent problems with crash tests, the size does matter. Even if the cage (passenger area, whatever you want to call it) is indestructible, the larger vehicle will always be safer. One of the major things the extra space gets you is more that has to be crushed before the vehicle stops. That means less of a shock to your system.

You're right that reducing g-forces is part of the equation, but "larger is better" is a blanket statement that isn't always true.

You are erroneously assuming that the extra space has been designed with energy dissipation in mind. Most body-on-frame vehicles have a battering ram chassis attached to a tin-foil body that is far from indestructible. The heavy chassis ensures that the vehicle keeps plowing into whatever you've hit like a bullet, while the weak body ensures that your ass is grass. If you've ever seen the results of a Ford F-150 offset frontal impact, you know that all that space doesn't mean shit if the passenger cage becomes part of the crumple zone and crushes the occupants. You need to both dissipate the energy slowly enough to keep g-forces "low" AND dissipate it outside the passenger cage. Neither are guaranteed by vehicle size.

 

[theeedude]

Originally posted by: thomsbrain

Originally posted by: Strk

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

The side-impact test isn't.

Besides the inherent problems with crash tests, the size does matter. Even if the cage (passenger area, whatever you want to call it) is indestructible, the larger vehicle will always be safer. One of the major things the extra space gets you is more that has to be crushed before the vehicle stops. That means less of a shock to your system.

You're right that reducing g-forces is part of the equation, but "larger is better" is a blanket statement that isn't always true.

You are erroneously assuming that the extra space has been designed with energy dissipation in mind. Most body-on-frame vehicles have a battering ram chassis attached to a tin-foil body that is far from indestructible. The heavy chassis ensures that the vehicle keeps plowing into whatever you've hit like a bullet, while the weak body ensures that your ass is grass. If you've ever seen the results of a Ford F-150 offset frontal impact, you know that all that space doesn't mean shit if the passenger cage becomes part of the crumple zone and crushes the occupants. You need to both dissipate the energy slowly enough to keep g-forces "low" AND dissipate it outside the passenger cage. Neither are guaranteed by vehicle size.

That's the old F-150. New one would kill everyone in a mini and keep on driving.
http://www.youtube.com/watch?v...t_0qIg&feature=related
Plus this is impact with stationary object, where all of the energy is bounced back into the vehicle, so heavier weight acts as an enemy, while when hitting a smaller car, it is your friend, because it reduces how fast you slow down.

 

[ponyo]

Cars have become much safer over the years but generally bigger is still safer. My dad was in a serious crash driving a compact and he vowed never to drive one again. I saw what it did, and I will not buy a compact or subcompact for any of my family member. I will not compromise the life of my family member for savings of driving a compact. Comfort, safety, use > any small saving of driving a compact.

Cars have improved tremendously since then but physics still apply

 

[43st]

This 5th Gear clip shows a new rated car, verse an older non-rated car. The results are a bit surprising considering what people think of the older Volvo's.

But that doesn't effect much when it comes to mismatched bumper heights, which is a big problem for lower, and usually smaller, cars. At least it's much much better than the old, no seat belt, steering wheel impaling cars of yesteryear.

 

[ponyo]

Another Fifth Gear clip showing SUV vs compact car

 

[AdamK47]

Originally posted by: JulesMaximus
I think everyone should drive a Ford Excursion. That way we would all be safe and nobody would ever get hurt in accidents.

BAN ALL SMALL CARS!!!

I think you're fibbin.

 

[Strk]

Originally posted by: Naustica
Another Fifth Gear clip showing SUV vs compact car

That's a pretty old compact though. Some of the biggest improvements in safety for compact sedans are recent. The frame improvements, especially the reinforcements and the impact distribution additions (the above link with the Modus shows that perfectly) alone would improve that hugely.

You also have some major safety technologies that were only added recently to small cars. I think 2006 was the first year any car company made six airbags and ABS standard on a their compact sedan(s) and it was just one car -- the Honda Civic (I believe their entire line has all of that standard now). Side-impact and curtain airbags and ABS were either option only, on specific trim levels or not even available on quite a few compacts. Ford made them standard on the 08 Focus, Toyota did on the 09 Corolla, Nissan on the 08 Sentra and the list goes on, but regardless, we're talking extremely recent.

 

[zoiks]

Originally posted by: JulesMaximus
I think everyone should drive a Ford Excursion. That way we would all be safe and nobody would ever get hurt in accidents.

BAN ALL SMALL CARS!!!

Troll posting doesn't really add much credibility to your arguments.

 

[JEDI]

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

 

[iamwiz82]

Originally posted by: JEDI

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

Here you go

Second link

 

[JEDI]

Originally posted by: iamwiz82

Originally posted by: JEDI

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

Here you go

Second link

"Vehicles are rated as Good, Acceptable, Marginal and Poor"

ahh.. this is iihs, not the fed's crash rating system. (1-5 stars)

the fed's use the same "comparable vehicle size" for front crashes, and suv/truck vs tested vehicle for side impact?

 

[Strk]

Originally posted by: JEDI

Originally posted by: iamwiz82

Originally posted by: JEDI

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

Here you go

Second link

"Vehicles are rated as Good, Acceptable, Marginal and Poor"

ahh.. this is iihs, not the fed's crash rating system. (1-5 stars)

the fed's use the same "comparable vehicle size" for front crashes, and suv/truck vs tested vehicle for side impact?

Yes, although I don't think their frontal test is offset. An accident is more likely to be offset, so it's kind of important.

The side-impact test is equal among vehicles though. The vehicle is stationary and a sled slams into the side of it.

 

[StageLeft]

Of course it matters. Momentum = velocity * mass is a tried and true formula and spells why despite a 5 star rating you don't want to be in a tiny car and the other guy's in a hummer with a trailer.

Two pool balls go toward each other at the same speed and hit dead-on. They stop. Now replace one of them with a bowling ball, what happens to the pool ball? Bounce back, rejected, and pwned. Just like in a collission between a "safe" sub compact and a mack truck.

 

[iamwiz82]

Originally posted by: Strk

Originally posted by: JEDI

Originally posted by: iamwiz82

Originally posted by: JEDI

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

Here you go

Second link

"Vehicles are rated as Good, Acceptable, Marginal and Poor"

ahh.. this is iihs, not the fed's crash rating system. (1-5 stars)

the fed's use the same "comparable vehicle size" for front crashes, and suv/truck vs tested vehicle for side impact?

Yes, although I don't think their frontal test is offset. An accident is more likely to be offset, so it's kind of important.

The side-impact test is equal among vehicles though. The vehicle is stationary and a sled slams into the side of it.

Is it though? I mean, a taller vehicle with the same height sled would be protected more, in theory. Hitting the area where the bottom of the door meets the body has more integrity since it runs across the entire car.

 

[Strk]

Originally posted by: iamwiz82

Originally posted by: Strk

Originally posted by: JEDI

Originally posted by: iamwiz82

Originally posted by: JEDI

Originally posted by: iamwiz82
Crash test ratings are only comparable among similarly sized vehicles.

Link?

Here you go

Second link

"Vehicles are rated as Good, Acceptable, Marginal and Poor"

ahh.. this is iihs, not the fed's crash rating system. (1-5 stars)

the fed's use the same "comparable vehicle size" for front crashes, and suv/truck vs tested vehicle for side impact?

Yes, although I don't think their frontal test is offset. An accident is more likely to be offset, so it's kind of important.

The side-impact test is equal among vehicles though. The vehicle is stationary and a sled slams into the side of it.

Is it though? I mean, a taller vehicle with the same height sled would be protected more, in theory. Hitting the area where the bottom of the door meets the body has more integrity since it runs across the entire car.

I just mean that the vehicle being simulated by the sled is the same. Like you said, the part of the car that gets hit will differ, which can affect the results. I mean, a compact will likely get most of the force into where the door meets the body. An SUV will probably take most of the force into the middle of the door.

 

[ElFenix]

when the thing delivering the kinetic energy is the same, the results can be directly compared across all tested vehicles. when the thing delivering the kinetic energy is not the same, the results are not 100% comparable against any other vehicle. however, vehicles within the same class are going to be close enough for a decent comparison.

 

[Pliablemoose]

Originally posted by: Naustica
Another Fifth Gear clip showing SUV vs compact car

I work in a trauma level 1 hospital, and I gotta tell you-all that this is reality. We don't even see the occupants of the smaller car in these type of accidents, they're pronounced dead at the scene. We do see the SUV drivers and passengers and they typically have minimal injuries.

If you pay attention to the clip, simple physics shows why the SUV defeats the safety features built into the smaller cars.

The side impact standards don't use large SUV height bumpers in their tests. The passenger compartment is essentially destroyed and side impact airbags don't stop the kind of damage that a SUV does to a small car.

I own and drive a Miata and an F250 SD diesel , so I'm on both ends of the problem, with smaller cars lie the Miata, the larger vehicle typically goes over the top of the smaller one in high speed front or rear collisions.

 

[vi edit]

I'd like to see them do the same "side impact" test and see what a 3800 pound full size sedan does to the very same civic.

I'm guessing it won't be as bad...but it still isn't going to be pretty. I really doubt the civic occupants would be walking to tell the tale.

 

[NAC]

This wasn't in the OP's question, but it cannot be forgotten:

Performance (and therefore indirectly size) also plays a big factor in avoiding accidents or changing the nature of accidents. It is hard to disagree that the driver of a Miata will probably be more injured than the driver of an SUV in a collision between the two. However, the Miata driver might successfully swerve to avoid the SUV. And the SUV driver might try to swerve to avoid the Miata, but instead roll over and plow off the road.

I think there are just so many variables when considering safety, and personally I don't know which ones to give the most weight to. I bought a Ford Freestyle (Taurus X), thinking that it has good size, good crash test ratings, and yet not as roll over prone as a similar sized body on frame SUV. I got bored with the Ford, so I got a small Audi wagon. It is similar in weight, yet much lower, smaller, higher performing, and has stability control. So in some accidents - say an SUV hits me from the side - the Ford is far superior. Yet in others - say a deer jumps in front and I have time to react - the Audi will probably be superior. I really hope I never have to find out.