Let me be the first to say "duh!".

Want to know something else? Midsize sedans won't do too well against full size sedans or SUV's. Why? Physics. No matter how great you build your car, you can't avoid physics. Since right now, just about all cars use the same materials, the bigger the car the more it weighs......therefore if you take a small sedan going 60 mph and a mid-size sedan going 60 mph, the mid-size sedan will do a hell of a lot more damage when it hits something due to it's greater mass.

It's pretty much the same as seeing a small sedan hit a deer (it'll normally mess the car up pretty bad) versus a semi hitting a deer where barely anything happens to the truck and the deer explodes into a thousand pieces.

Whenever you ram two vehicles of a significantly different size into each other head on, the smaller vehicle will always lose.

Now, as for ""Fifty-five was adopted to save fuel, but it turned out to be one of the most dramatic safety successes in motor vehicle history," Lund concludes. "The political will to reinstate it probably is lacking, but if policymakers want a win-win approach, lowering the speed limit is it. It saves fuel and lives at the same time.""

Yea, well unfortunately politicians use planes and never have to drive to work. They'd never even consider lowering speed limits (when there's no reason that highway speed limits can't be higher, you just have to teach the morons to actually drive sanely) if they had to deal with taking an extra 10-20 minutes (or more) getting to work and going home at the end of the day (not to mention if you ever have to travel long distances by car where that significantly lower speed limit would eventually add HOURS to your trip).

"deformable barrier, which most of the time is not accurate in the real world."

Exactly. Which is why they should have the barrier moving towards the car as well in a offest frontal crash test, which would be a lot more accurate then to just having a car moving towards a stationary barrier. I mean, the results don't lie. The Fit for example was rated one of the best sub-compact cars in an offset frontal barrier crash test, but when it encounters another moving object in an offset frontal crash test it does poorly.

p=mv or momentum equals mass times velocity. f=ma or force equals mass times acceleration. It doesn't take a 6th grader to figure out more mass means more momentum and more force.

Now a stationary object has no velocity or acceleration. This means no opposing force or momentum adding to the impact. The stationary object just opposes the amount of force acting on it by the car, which will be no greater then what the car's mass is and its instantaneous acceleration at point of impact is. So in this case, smaller mass wins. Again doesn't take a 6th grader to figure out 0 times anything equals 0 or that less mass equals less force.

The US Department of Transportation figures are that there were 44,525 fatalities in 1973, and 45,523 in 1974.

honestly, the argument of having a smaller car to avoid an accident in the 1st place is moot, at least here in where i'm at (philippines). the cars you see overspeeding on highways and expressways and even on regular roads are the subcompacts, especially the fit (jazz here) and yaris (vios here, though there is a yaris too but it's the smaller one).

...it's like they got something to prove or whatever.

i guess it's darwin's theory of evolution at work.

Breaking news! The laws of Physics still work!

SO IF i understand all this.. the danger are BIG SUV!!! or should we ban small cars?

i dont think we need all those sedan, trucks & SUV.. too many on the road... and were just going from A to B.... ! with only 1 person in the car...

the hell... we should all have motorcycle...! 600cc at most...

LOL @ everyone that bought the smart for two and said it got good crash raitings!

WHAT?

Next you'll be telling me that there is no magic indestructable metal called "Tridion"

Of course those small cars do worse, as long as there are Camrys, Accords, Avengers, Malibus, Fusions, Sebrings, and Sonatas on the road I will never own one of those little death traps, you know Yaris', Fits, Aveos..... If you own one of those little cars and you can not take a hit from a Malibu, there is no way you will be OK if you hit something bigger Highlander, Explorer, Grand Cherokee......

To some extent you could look at these results two ways. The article says small cars subject their occupants to greater dangers.

But you could also say larger cars subject occupants of OTHER cars to greater danger.

That latter view doesn't hold up 100%, as a smaller car faces greater risks when encountering non-car movable objects, like safety barriers and such. However

However, I think this should be kept in mind when considering buying a car size just for safety factors. Do you accept risk for yourself to save gas, or do you put others at risk in order to have more cup holders?

Regarding highway safety effects of 55mph limits, I've always wondered how much those studies consider other safety improvements that were implemented around the same time. Things like mandatory installation of seat belts, crush zones in car designs, better safety barriers on highways, improved emergency response and medical techniques. All of these things made great improvements during the '70s, and I suspect they had a much stronger influence in reducing fatalities than 55mph.

@KW

The article says that the subcompacts all did well against stationary objects, it was only when they took something twice the size and moving towards the subcompact at the same speed the subcompact was traveling that they got destroyed. Therefore, safety barriers are not an issue because they're not moving and have no force to exert on any car (regardless of size).

All of these idiots like the people who wrote this article would have us all driving M1 Abrams tanks everywhere we go because "you won't get hurt in a crash".

So perhaps car makers should be forced to lower the weight of their large vehicles rather than install more airbags in their small vehicles. These would accomplish the same thing and the former would be much better for emissions.

Come on, you'd have to be an idiot to think a Yaris will hold up to an Expedition because of it's "Five Star Rating!" I bought my MINI Cooper S for fun, just like someone buys a 350Z for the same thing. Safety wasn't much of a factor when making my purchase, as it really shouldn't be when purchasing a car as small as a Smart Car.

I'm sure my MINI would hold up well to 1990 trucks (due to their relative inability to absorb any kind of energy), but the fact of the matter is, most vehicles would cream the MINI.

Corvette, 350Z, MINI, Z4... you buy these cars for fun, not for safety. Some people are really hell-bent on safety by purchasing their 6000lb Escalades with 30" Chrome rims. 35 cars out of a million mini-cars dying? 0.0035% of dying out of being part of the 35 in the million in your state. But I guess when you say you have a three time higher chance of death, it really pushes your point. 576,000 to 1 chance you get struck by lightning... better not go outside unless you put on your rubber boots!

Articles like these push the giant super-SUVs. We small cars wouldn't have to worry if people didn't have to purchase 6,000 vehicles that have twenty-three cupholders.

Anyone who thinks a modern minicar can stand up to a modern SUV is silly.

Hey, let's test big motorcycles against minibikes!

In Texas, the right of way is this: I am bigger than you, move over.

WVO:
Hey, let's test big motorcycles against minibikes!

the law in texas is,"go slow in the passing lane". They follow that law when they drive in other states.

Hold on, isn't the IIHS funded by auto insurers? And don't they charge more to insure bigger, pricier cars?

Totenglocke:

know where i can buy an m1 abram then? or a challenger? :D

@ WVO [ Texas, the right of way is this: I am bigger than you, move over ]

That IS pretty much is the rule here! I was driving my little sisters newer Civic going 75-80 and big trucks going slower in the fast lane infront of me wouldnt move over! I had to go around them, and get back infront. And I was getting shoved around by big suv's every other minute. I just hate driving small cars here! Their fine for the city, but once on the freeway or interstate, move over! Its annoying as f*ck! I wish she would go for a 'Z' or somthing. At least ya got speed.

"The Mercedes C class versus Smart Fortwo: After striking the front of the C class, the Smart went airborne and turned around 450 degrees."
DUH!!!!
I have always liked the SMART FOR 2, and its pretty frikkin safe with that "protection cell" or whatever SMART calls it, but because of its tiny little self, the G-force of that is bad enough without taking to mind if say I were to peg it at 45mph or greater in my Tundra.

I still have my '93 Corolla DX from waaaay back in the good ol' college days, and will not take it out on the freeway! This thing has NO balls and ya gotta put ure foot to the floor to do anything. It's terrible on I-35. Usually I find a 18 wheeler and stick behind him. He can't stop fast anyway and the wind track helps my mpg [not that it really matters on this car anyway].

I love my 5.7 Tundra! As long as its less then $3 a gallon, ima drive this as my daily. Plus somthing about driving this truck puts my mind at ease. I feel safe. I feel secure. I know if I get into an accident im going to come out just fine. Yea, it got the 4 star crash test rating, but I got a Westin cattle gaurd on the front of it to take care of that. People usually just feel more secure in these larger vehicles, so no madder what, they will ALWAYS SELL!

The Civic looks to have done much better then, say the Yaris which looks TERRIBLE!!

I WISH I could have seen an Aveo getting wacked. I bet the Yaris would hold up better...

Why would they smach a Mercedes into a Smart instead of... a Malibu?

If pop culture has taught us anything, it's that spoiled teen sluts buy Mercedes' and drunkenly crash into things alot.

Some of the comments about hitting a stationary object versus a moving object makes a big difference are misleading and wrong. I use to think this until I spoke to a Physics teacher with a PhD about it. It has to do with instantaneous acceleration and the conservation of energy rule.

When 2 objects collide the velocities are not added or the velocity of one vehicles isn't equal to the approach spead, therefore, it isn't any different than that object hitting a stationary object if they are both travelling at the same velocity and have the same mass. Two equal cars travelling at 55 hit head will produce the same energy per car as the car hitting a stationary object at 55. You can't get something from nothing. This is why they use the stationary object test. It is a good indicator of a car hitting any object at that speed and far less expensive. Cmon, these guys aren't dumb so don't assume you know better when you couldn't.

The reason there is usually more damage when 2 cars collide is because of the deformation of each object into each other which causes compression and stress in different regions of the car in comparision to that of a car hitting a stationary object. You can't use this type of test when designing a vehicle because it is too unpredictable and every collision would produce a different result. Then what would you do?

The larger the mass your car has the safer you will be on average. However, the engineered structure of the car can also greatly improve the performance of the vehicle. Look at race cars with roll cages. Very light but also very strong. Combine that with crumple zones and you get more protection. F1 and Indy are extreme examples of how both these things work together to keep drivers safe at high speeds. Unfortunatelly this technology is also expensive and unpractical so it isn't put into regular cars.

Quote: "smaller mass wins"

Hmmm? You should redo your grade 6 physics. It's easy pontificate about Newtonian physics, it's another to understand and use them (physics equations and laws) in a way that makes sense. We're not talking about billiard balls here, we're talking about the vehicle's ability to dissipate force and protect the passenger compartment. Cars of the 60's - large and cumbersome - were extremely unsafe, but had large mass. By your flawed logic they should be safe but weren't. The problem with these smaller cars is the difficulty in engineering force distribution with the light materials and short frontal area. Naturally a 2.9 tonne SUV will annihilate a Honda Fit - the Fit cannot absorb that much energy. Unfortunately we live in a
world, especially the US, when there is a preponderance of large vehicles and not smaller fuel efficient cars. It would nice if engineers could design protection in those vehicles without making them bigger.

Wow, I am well aware it is a little more complicated then that, but f still equals ma. If you want, I can list other forces at work, like friction force equals Mu times Fn or coefficient of kinetic friction times the normal force in which case the normal force equals the force due to gravity or mg where m is mass and g is the acceleration do to gravity. Then you have compressive/spring forces provided by Hooke's Law. The fact is, I can list every force at work in a crash, but the fact remains, no acceleration or mass, no force. Less mass or acceleration, less force. I can also list all the energies at work too. The fact is, however, its the force that does the damage, not the energy.

Also, I think you need to reread what I wrote. "The stationary object - . So in this case, smaller mass wins." So in theory, since a stationary object has no acceleration, it only applies an opposing force against an object which hit it, or f=ma. And once again, smaller mass, less force.

Avatar, I'm glad that you remember your first year physics equatons, but I still disagree with your logic. I'm well versed in physics and I'm not going to discuss examples of inelastic collisions nor am I going to demonstrate the derivation of said formulae here either. I do believe that it's much more useful to calculate kinetic energies before and after vehicle collisions, and determining how much of the energy is dissipated. Using a motorcycle helmet as an example, it's job is to dissipate as much energy as possible without transferring it to the person's head. That's why helmets don't bounce (much) when dropped. Yes, you can calculate the forces involved with the deceleration. And sure, you can calculate the momentum as well. N.B. that when a person wears a helmet (as an example), the mass is increased, therefore, the force is higher for the helmet with a person wearing it in contrast with a person not wearing a helmet, given the same deceleration in an impact situation. Simple mass and acceleration. However, the energy transfered to the person's head is not the same for someone not wearing a helmet and being involved in a similar collision. That being said, the same goes for vehicles - there needs to be a greater emphasis on energy dissipation using whatever technologies are possible. Large vehicles should also have energy absorbing technologies so that the energy is not transferred to a smaller vehicle in a collision. Fortunately, cars today are still safer than cars of yore, but can be better.

Fine, want to use energy, here it goes. In the helmetg system, I think we can both agree there is kinetic energy which is 1/2mv^2. No using f=ma, we can say m=f/a. Ek=1/2(f/a)v^2, 2Ek=(f/a)v^2, (2Ek)/v^2=f/a, a((2Ek)/v^2)=f. So the force changes with the size of the kinetic energy now, or the helmet distributes as much force as possible. Or you can go the other way and say Ek=p^2/2m So momentum matters as well. Again, there are more energies at work then just kinetic. The nice part about physics, there is generally more then one way to go about getting the answer, since work, energy, force, momentum, and even kinematic equations(which is the real first year stuff) can all be interchanged because they all use mass, velocity, acceleration, and distance. And mass will always equal mass, etc etc. There is no wrong way to get the answer, only easier ways. We can go farther still and use calculus since calculus after all was invented to do physics, though is used in other areas now. The question is what variable are you looking for, you are looking for energy, I am looking for force. Both, as proven above, can easily be interchangeable.

This just in - your tax dollars have determined that a bicycle will not hold up well against a freight train in a collision.

Avatar, this is my last comment on this topic; feel free to reply ad infinitum. I still haven't discovered the thrust of your argument besides manipulating simple physics equations. Yes, you can rearrange and substitute the variables in the equations, but you need to explain what you want to do with that particular value. I still maintain that maximum dissipation of the kinetic energy in a collision is ultimately one of the principal factors the automotive industry should be striving for. What I'm trying to convey is that in this country of vastly dissimilar sized vehicles, more effort and research needs to be concentrated on making smaller vehicles safer and larger vehicles safer *for* smaller vehicles in the event of a collision. Ciao.

In any crash, both cars experience the same amount of impact (assuming they hit each other).

That amount of force equates to a greater vector change in a less massive vehicle as opposed to a more massive one (why a train doesn't stop when it hits a car).

The other issue is the time the vector takes to change. A large car means longer crumple-zones means slower acceleration.

All other thing being equal, a passenger in a large car will do better against a brick wall than one in a small car because while the speed-change remains the same (40-0 in a 40mph impact), the actual stopping time is longer is a larger car (so the force is applied over a longer time).

Interestingly, this works both ways in a car-on-car collision; with the crumple zone spreading out the impact for both vehicles.

There was a pretty good crash test of Top Gear (Large Family Volvo aganst a Smart 42), lok for it on the tube, and smart did hold up to it's promise.
Test there was successful.
Why it is not here, and what exactly went wrong?

There was a pretty good crash test of Top Gear (Large Family Volvo aganst a Smart 42), lok for it on the tube, and smart did hold up to it's promise.
Test there was successful.
Why it is not here, and what exactly went wrong?