5th generation civic hatchback - improving aerodynamics

[3-Wheeler]

Originally Posted by Xringer

If it wasn't for those big heavy vehicles that I have to share the highways with,
I wouldn't mind a lighter car..

I feel a little safer in a heaver vehicle.. If someone T-bones me on a snowy
day, I don't want to be sitting in a Honda Fit. But, that's just me..

Hi Xringer,

Talking about heavier vehicles...

Did you hear about the SUV driver that was killed two years ago in Devil's State Park in Wisconsin?

Several motorcycles were coming from the opposite direction and one lost control in a sharp turn. The motorcycle did the classic "high-side", which is to say that it lost grip, then regained it, and spit the rider off as the bike flung into the air.

It sliced right through the drivers compartment of the SUV with predictable results...

I ride a motorcycle in warmer weather, so I really don't fret when driving a smaller car. When it's your time to go...enuf' said...

Jim.

[Xringer]

Besides the T-bone, one of the things that worries me, is being bumped by someone in another lane.
The second worry I have driving here in MA, is being rear-ended.
I'm not sure if weight helps in those cases, but it might, if the other car is a lot lighter.

Last month, a couple of people were killed just up the road. A Toyota Corolla was
waiting in line at a red light, when some elderly guy T-boned them on the drivers side
with a mid-sized American sedan. The driver of the Toyota went right into ICU
and his wife went to the morgue.
The driver of the Chrysler lost his wife too. I don't know how that happened.
No seat belt maybe.. Anyways, it was a low speed crash.

I also like the visibility that I have in my SUV.. I'm up high enough to see
up the road (over the tops of cars) and I'm easy to see too..

[NeilBlanchard]

Yes, but tall SUV's also block the view of other vehicles.

[3-Wheeler]

Originally Posted by NeilBlanchard

Yes, but tall SUV's also block the view of other vehicles.

Good point!

Talking about safety, didn't Mike (from AeroCivic) mention that his boat tail helped him when someone rear-ended his car?

I like the idea of having more length back there!

Jim.

[Xringer]

Originally Posted by NeilBlanchard

Yes, but tall SUV's also block the view of other vehicles.

That's why I don't like to drive behind SUVs.. I prefer to drive behind sports cars, with their tops down..

Actually, I don't really drive behind too many cars at all. I drive the
speed limit (and under), and everyone else is in some kind of a race.
They just want to get to the next stop light, so they can sit there
and text with both hands, instead of just one.

If I'm out on the highways, very few people will stay behind me
for more than a minute or two. Then, it's off to the races..
Heck, even if I was driving 85, there would still be people passing me,
while talking on their cell phones..

[eRoc]

Originally Posted by 1.5Ldave

Weight has no bearing on how well a vehicle will do in a crash. Size for the most part doesnt either, granted to dont end up underneath one of the collosus vehicles people drive to "feel" safe. Ill choose quality engineering over some big heavy box for safety any day of the week and twice on sunday.

f150 and mini cooper 40 mph crash comparison



Both of these vehicles hit the exact same off-set barrier at 40mph. Now keep in mind that this is not a test of how the two cars would fare in a head-on collision with each-other. This is simply how the cars did versus an off-set crash test. In fact all you have to do is look at the dummy’s legs and you can get an idea of what would happen if you hit a wall in either car. The MINI had almost no intrusion which “indicates that the driver’s survival space was maintained very well” - the F150 on the other hand had “Major collapse of the occupant compartment that left little survival space for the driver.”

I beg to differ with this argument. Weight and size do have a big part of how vehicles do in a crash.

Take the vehicles in that video. Mini Cooper maybe weighs 2200lbs. F-150 weighs approx 5000 lbs (guessing). You wouldn't think that at 40mph the Ford would carry more momentum into the crash than the mini cooper? What if we took an f150 made out of Nerf and crashed it into a wall at 40mph? Do you think it would have the same effect? I doubt it would crumple further than the front bumper.

Size also matters. Take a number two pencil. Snap it in half. Then take that half and snap it in half. Then take the smaller half and snap that in half. It gets increasingly harder each time.

Finding the balance inbetween all of this is why engineers get paid the big bucks.

Physics....

P.S. First time poster. I'm going to post in the welcome forum but I found this thread through Treehugger.com (actually found Aerocivic and there was a link to this thread). I'm intrigued by all of this so I will be posting more often.

-Eric

[Funny]

Great argument. We all need a reality check now and again. The physics won't lie, so keep the scientific comments coming! Welcome to Ecomodder!

[Fubeca]

Originally Posted by 1.5Ldave

Weight has no bearing on how well a vehicle will do in a crash. Size for the most part doesnt either, granted to dont end up underneath one of the collosus vehicles people drive to "feel" safe. Ill choose quality engineering over some big heavy box for safety any day of the week and twice on sunday.

f150 and mini cooper 40 mph crash comparison



Both of these vehicles hit the exact same off-set barrier at 40mph. Now keep in mind that this is not a test of how the two cars would fare in a head-on collision with each-other. This is simply how the cars did versus an off-set crash test. In fact all you have to do is look at the dummy’s legs and you can get an idea of what would happen if you hit a wall in either car. The MINI had almost no intrusion which “indicates that the driver’s survival space was maintained very well” - the F150 on the other hand had “Major collapse of the occupant compartment that left little survival space for the driver.”

In my opinion this is more an indictment of Ford safety engineering at the time than a universal rule about weight. Although it takes more strength to make them survive the same crash with a stationary object, heavy vehicles can be safe for their occupants. If you look at the next generation (2004-2008) F150 in the same crash test the occupant compartment is maintained very well.

[Jethro]

This is interesting... My buddy got head on'd by a drunk driver in his 00 Ram Cummins. (oncoming vehicle was a 98ish Dakota). Buddy was doing 70, other driver was unknown.

The Ram was destroyed, yes, but passenger cabin was FINE. The door would have opened easily if the fender had not been in the way.

The Dakota on the other hand... well, it took me a while to figure out WHAT he hit. The cab was almost crushed shut.

When it comes to being in an wreck, I'd much rather be in the vehicle with more mass. I've always felt 300x safer in my truck than in ANY car I've ever been in.

Crumple zones and all work great, up to their designed maximums. Once you exceed them, you're SOL in a little tin can.

[benbenben]

Auto accidents are complex dynamic and can be highly individualized. The same could be said of people. When analyzing either,the complexities often overwhelm. Biases and distortions leap in as people notice recurring pattern and mistakenly assign causal rather than coincidental relations.

When we think about a 1967 Cadilac Sedan Deville in a head on collision with a 2003 Honda S2000, we tend to judge the safety of each vehicle by the potential threat to passengers in that ONE accident. That is a falacy in logiic. The passengers in the S2000 were in a completly different accident (thay hit a Caddillac) than the passengers in the Cadillac (they hit an S2000).

Safety might usefully be compared analyzing potential passenger outcomes had each vehicle been in a head on accident withthe same thing: a GMC Jimmy, or a tree, or a concrete barrier, but not by different objects for each vehicle.

That is probably a large factor in the widelyheld belief that heavier cars are safer...inequitable comparicons. I have hit a concrete barrier in an S2000 and i have been in an accident in a Deville. I would not have survived if I had hit the concrete barrier in a Deville instead of the S2000.

There is truth to the logic that a stronger shell can be constructed with more mass, but just because something is heavier does not necessitate it is stronger. Racecar cockpits are very light and driver sometimes survive impacts over