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Okla-homey
9/3/2008, 07:58 AM
A "certified accident reconstructionist" and OHP trooper told me yesterday that the best thing to do if you are confronted with an unavoidable head-on collision is to speed up. Something about the car with the greatest velocity does better in such crashes.

I never took physics, but it seems counterintuitive to me.

what say you?

:pop:

batonrougesooner
9/3/2008, 08:09 AM
The more kinetic energy you impart on the oncoming object means less said object imparts on you?

I could have given you a more intelligent answer ten years ago.

Vaevictis
9/3/2008, 09:22 AM
Hard to know for sure without knowing more information about the physics of car crashes, but Newton's Third Law sort of says that you should be suspicious of this claim -- you get hit just as hard as the other car does.

There may be factors that make the trooper's statement true, but without more information, I'd just punt to the Third Law and say what you said -- that doesn't sound right.

Also, based on the information you gave, I suspect the guy is making a simple logic error. The facts may be that the person going faster does better in a head-on, but from that, the guy is drawing the conclusion that you're better off at a higher velocity.

This isn't necessarily true. You can speed up, do better than the other guy, and still do worse than if you hadn't sped up at all. It shouldn't matter who comes out better, what should matter is what results in the best outcome for the passengers in your vehicle.

OUDoc
9/3/2008, 09:25 AM
Still, how much time do you have to speed up in a situation like that? If you have time to consciously speed up by any appreciable amount, you should have time to stop or avoid the collision. Overall, I can't see where it would matter.

soonermix
9/3/2008, 09:29 AM
you see...
as you speed up you are trying to run through the other car just like the demolition derby you win

Veritas
9/3/2008, 09:32 AM
Jeebus. Sounds like there is a reason that guy is a state trooper and not something with a higher minimum threshold for intelligence. Increasing speed is going to increase the total kinetic energy in play. Dude needs to learn more about inelastic collisions and the conservation of momentum.

batonrougesooner
9/3/2008, 09:35 AM
Jeebus. Sounds like there is a reason that guy is a state trooper and not something with a higher minimum threshold for intelligence. Increasing speed is going to increase the total kinetic energy in play. Dude needs to learn more about inelastic collisions and the conservation of momentum.

Ahhh.

You mean the Adrian Peterson effect?

Okla-homey
9/3/2008, 09:36 AM
Okay, here's what I was thinking in my liberal arts brain that is seasoned with some basic aerodynamics and bombing theory and practice.

If you could speed up and do better than the other guy, than theoretically, if you could go fast enough in the opposite vector, a bullet fired at you couldn't hurt you.

OU4LIFE
9/3/2008, 09:37 AM
it's a simple matter of just getting it up to 88 mph...then you can just go right through it.

batonrougesooner
9/3/2008, 09:39 AM
it's a simple matter of just getting it up to 88 mph...then you can just go right through it.

Right back to good old 1955.

Veritas
9/3/2008, 09:49 AM
Ahhh.

You mean the Adrian Peterson effect?
Great example, actually. The trooper's example is like saying that if one of us was to run as hard as would could at AD, the faster we go the LESS likely it is we walk away with full body bruises.

Me, I'd rather shake AD's hand and walk away with an autograph than take a run at him and limp away with some broken-*** bones.

BigRedJed
9/3/2008, 10:16 AM
Not a physics guy, but that doesn't make a whole lot of sense. What does make some sense to me is the idea of aiming for a car that you are about to broadside in an intersection. I remember reading that a while back, with the idea being the other car would be gone from that space if you steered toward the back end of it instead of giving in to the natural tendency to veer away. Sort of like when NASCAR guys steer towards the car in front of them that is spinning out, with the expectation that it won't be there when they get there.

Jerk
9/3/2008, 10:22 AM
As long as the car doesn't come up and over my hood, and through the cab, then I'll live.

Sooner Eclipse
9/3/2008, 10:24 AM
Its been a while but --- theoretically this is true if you ignore mass in this scenario. Practically, it doesn't work given the large amount of mass involved in a car crash.

Think of it this way, if a Camry hit a Surburban sitting on the side of I35 at 80mph don't you think the damage to the Camry is going to be greater than if you hit it at 60?

Now, if 2 Camry's with the same ammt of mass hit going different speeds, the one going faster will continue forward at a much slower speed. The slower one will deflect backwards. If the Camry (doing 80) hits a Surburban (doing 60) The surburban continues forward. At some point if you continue to increase the speed of the camry, its energy will offset the mass of the Suburban, but in all cases you increase the damage done and the delta V imparted to the occupants.

I haven't done the math but you get the idea.

yermom
9/3/2008, 10:35 AM
it's probably better if the nose of your car isn't diving as you hit the other car...

(as in braking)

on the other hand, what if the other participant in the collision is a brick wall?

Vaevictis
9/3/2008, 10:56 AM
Now, if 2 Camry's with the same ammt of mass hit going different speeds, the one going faster will continue forward at a much slower speed. The slower one will deflect backwards.

Yeah, but they'll both have the exact same dV (albiet in opposing directions), so the consequences for the occupants would be the same in both cases. Right?

Sooner Eclipse
9/3/2008, 11:02 AM
it's probably better if the nose of your car isn't diving as you hit the other car...

(as in braking)

on the other hand, what if the other participant in the collision is a brick wall?

Angle of impact, speed, mass, weather, physical shape, etc. all play a part. No two crashes are ever the same. Analysis of a crash is always subject to conditions at the scene and forces being applied as well as the physical properties of the objects involved.

as to the brick wall. That to depends on the strength of the wall and the mass and speed of the moving object. A semi tractor trailer doing 25 goes through most walls without much change in speed. The motorcycle rider doing 60 makes a nice grease spot and the maintenance guy has to power wash his brains off the intact wall.

Sooner Eclipse
9/3/2008, 11:09 AM
Yeah, but they'll both have the exact same dV (albiet in opposing directions), so the consequences for the occupants would be the same in both cases. Right?

if mass is the same and the angle is perfectly direct, the camry doing 50 will slow down to (example only) 5 mph still going forward. The camry doing 40 will accelerate in the opposite direction appx at the same speed (5mph)

The big factor in this is mass.

Vaevictis
9/3/2008, 11:12 AM
if mass is the same and the angle is perfectly direct, the camry doing 50 will slow down to (example only) 5 mph still going forward. The camry doing 40 will accelerate in the opposite direction appx at the same speed (5mph)

So yeah, in other words, dV is the same -- faster camry gets -45 in one direction, slower gets -45 in the other. Impact on the occupants, all other things being equal, is the same.

Sooner Eclipse
9/3/2008, 11:13 AM
So yeah, in other words, dV is the same -- faster camry gets -45 in one direction, slower gets -45 in the other. Impact on the occupants, all other things being equal, is the same.

Assuming mass it the same, theoretically, yes.

badger
9/3/2008, 11:16 AM
A "certified accident reconstructionist" and OHP trooper told me yesterday that the best thing to do if you are confronted with an unavoidable head-on collision is to speed up. Something about the car with the greatest velocity does better in such crashes.

I never took physics, but it seems counterintuitive to me.

what say you?

:pop:

Ok, let's do a visual demonstration:
http://www.physlink.com/estore/cart/item_images/613_xl.jpg
This is called the "Balance Balls" model. When a ball (or in your case, a car) hits three stationary balls (or in your case, "parked cars") the impact will not effect your ball ("car") but rather, the front ball ("car") in this line. The faster the ball ("car") moves, the farther the front ball ("car") moves.

For an additional demonstration, let us grab an electric fence, shall we?

OUCH! No, just kidding. That was acting on my part, but I bet you feel a lot of pain now, don't you? You see, this is because I initiated the force against the electric fence while touching you, and therefore, YOU received the shock. This is the same for cars, whereas if one car "touches the electric fence" while touching your car, your car will get the prime shock. Imagine the shock if you drove really fast compared to just a slight bump!

:D Ok, so I am neither physics nor smartee, but I thought I would have a break from the political discussions. Please do not take my silly demonstrations (which probably read like a children's book) seriously. All in fun.

M
9/3/2008, 11:20 AM
The simple explanation is that speed kills.

Formula for kinetic energy is

KE = ½ MV²

KE=Kinetic Energy
M=Mass
V=Velocity (meters per second)

So, as you speed up, the amount of kinetic energy increases. However, because the equation has velocity squared, the kinetic energy increase is exponential compared to the speed increase. So, when the velocity (speed) doubles, the kinetic energy quadruples. Even a small velocity increase creates a disproportionate increase in kinetic energy. A 5 mph speed increase from 30 mph to 35 mph increases the kinetic energy by a third. In a crash, you can't do anything about the mass of your car, but you can change its velocity to reduce the amount of KE.

soonerbrat
9/3/2008, 11:22 AM
i only made a B in physics 1. I can't answer that. I couldn't even tell you how fast 2 penguins were skating on ice.

gh55
9/3/2008, 11:42 AM
the ohp is hoping you hit each other hard enough to disinegrate. less
for him to clean up.

Sooner Eclipse
9/3/2008, 11:44 AM
the ohp is hoping you hit each other hard enough to disinegrate. less
for him to clean up.

Heh, :eek:

Ike
9/3/2008, 12:09 PM
I think the guy may be off his rocker.


As a simple thought experiment: Imagine you are sitting in your parked car and get hit head on by a Semi doing 70mph. It's pretty much a given that you are going to go splat.

Now imagine that you collide with the same semi while you are doing 95mph down the highway. Now you don't just go splat, but you probably completely liquify as well.

Echoes
9/3/2008, 12:14 PM
Jeebus. Sounds like there is a reason that guy is a state trooper and not something with a higher minimum threshold for intelligence. Increasing speed is going to increase the total kinetic energy in play. Dude needs to learn more about inelastic collisions and the conservation of momentum.

This.

Truthfully, you probably can't make a blanket statement like this. Way to many factors to play into a car crash.. but if you tried to make a blanket statement, it would be what Veritas said.

Okla-homey
9/3/2008, 12:24 PM
Still, how much time do you have to speed up in a situation like that? If you have time to consciously speed up by any appreciable amount, you should have time to stop or avoid the collision. Overall, I can't see where it would matter.


Context of our discussion: Imagine a scenario in which you're traveling at highway speed and all of a sudden a guy in the opposite lane who fell asleep careens into your lane. You can't avoid a collision because there's no where to go on your right (no shoulder, trees), and you don't want to do anything sudden to your left because he might wake-up and overcorrect or you could lose control or both. Slamming on brakes doesn't take you out of harms way even if you could stop after laying down 100 feet of skid marks. Thus, according to this guy, just floorboard it.

Imagine both vehicles are of comparable size and weight.

My question: does this make sense, scientifically speaking? It seems to me it would take cajones the size of pomegranites even if it does.

mdklatt
9/3/2008, 12:54 PM
Context of our discussion: Imagine a scenario in which you're traveling at highway speed and all of a sudden a guy in the opposite lane who fell asleep careens into your lane.


Is the guy right next to you or ahead of you? Is he going the same speed? If he veers into your lane while he's alongside, you might be better off speeding up if you can get out of his way and avoid the collision altogether. If he's ahead of you (and going slower), speeding up is only going to make it worse.

EDIT: If it's an oblique collision you might be better off speeding up so that you push him off to the side when you hit rather than coming to a stop altogether. At least that's the way it works in Grand Theft Auto. :cool:

OUDoc
9/3/2008, 12:58 PM
My question: does this make sense, scientifically speaking? It seems to me it would take cajones the size of pomegranites even if it does.

To me, no, it doesn't make sense that increasing speed would be better.

yermom
9/3/2008, 01:11 PM
The simple explanation is that speed kills.

Formula for kinetic energy is

KE = ½ MV²

KE=Kinetic Energy
M=Mass
V=Velocity (meters per second)

So, as you speed up, the amount of kinetic energy increases. However, because the equation has velocity squared, the kinetic energy increase is exponential compared to the speed increase. So, when the velocity (speed) doubles, the kinetic energy quadruples. Even a small velocity increase creates a disproportionate increase in kinetic energy. A 5 mph speed increase from 30 mph to 35 mph increases the kinetic energy by a third. In a crash, you can't do anything about the mass of your car, but you can change its velocity to reduce the amount of KE.

how YOU doin'?

olevetonahill
9/3/2008, 01:15 PM
Either way ya gonna get ****ed up.:eek:

jkjsooner
9/3/2008, 01:16 PM
A "certified accident reconstructionist" and OHP trooper told me yesterday that the best thing to do if you are confronted with an unavoidable head-on collision is to speed up. Something about the car with the greatest velocity does better in such crashes.

I never took physics, but it seems counterintuitive to me.

what say you?

:pop:

Being in a heavier car could help you even though the greater weight increases both the kinetic energy and momentum. The heavier car would decelerate slower meaning less force would be applied to the driver and also more compression to the lighter car.

I can't see how this logic would apply to a car of equal mass going faster though.

It takes a lot more than rudimentary physics to answer these questions though. There are so many variables - how much can the car can absorb the energy rather than the driver, etc.


The real question is, even if this patrollman is correct, do we really want them to advise us to do something that is in our best interest but would clearly not be in the interest of the other driver?

I would like to say I wouldn't even do that on ethical terms even if I knew it would be better for me. In either case, as a neutral professional who is responsible for everyone's safety, I sure would never advise others to do so.

I guess we buy bigger cars for safety (assuming you're colliding with a smaller car) and that does jeopardize other's safety for your own so it's sort of the same thing....

I've always wondered if I had an 18 wheeler coming at me head on and my only out route was to plow into a pedestrian, which route would I take? Without a chance to ponder and acting only on instict it would probably be the latter. If I had time to think about it I would like to believe I would at least consider the former.

Veritas
9/3/2008, 01:18 PM
Truthfully, you probably can't make a blanket statement like this...
Oh, but this is the internet. You can't NOT make blanket statements. That's why Al invented it.

soonerbrat
9/3/2008, 01:18 PM
this is making my head hurt

olevetonahill
9/3/2008, 01:19 PM
this is making my head hurt

Take 2 aspirin and Call me later if it isnt better.:)

jkjsooner
9/3/2008, 01:35 PM
Ok, let's do a visual demonstration:
http://www.physlink.com/estore/cart/item_images/613_xl.jpg
This is called the "Balance Balls" model. When a ball (or in your case, a car) hits three stationary balls (or in your case, "parked cars") the impact will not effect your ball ("car") but rather, the front ball ("car") in this line. The faster the ball ("car") moves, the farther the front ball ("car") moves.





Yeah, but your ball is decelerating very rapidly as well and therefore is experiencing lots of forces. Plus, this is an elastic collision whereas in car accidents much energy is going to be absorbed by the cars/humans/etc - not good.

Veritas
9/3/2008, 01:37 PM
Plus, this is an elastic collision whereas in car accidents much energy is going to be absorbed by the cars/humans/etc - not good.
Bingo. Inelastic vs. elastic is the crux of this discussion. Auto collisions are highly inelastic.

Even if they were highly elastic, the higher the forces of deceleration on the human body, the greater the chance for serious injury.

Ike
9/3/2008, 01:49 PM
Bingo. Inelastic vs. elastic is the crux of this discussion. Auto collisions are highly inelastic.

Even if they were highly elastic, the higher the forces of deceleration on the human body, the greater the chance for serious injury.


It's the inelasticity that makes it possible for car designers to engineer cars that can keep you relatively safe during a crash too....the forces of deceleration would be much higher if crashes were elastic...

Anyway, considering Homeys context there is only one way that this advice could possibly make much sense, and thats to make sure that your bumper isn't driving down lower than the other guys, which could make a difference in some small subset of cases.

Otherwise, your best bet is to get drunk/stoned/wasted really super fast so that you don't care what happens and thus, you don't tense up all the muscles in your body. The act of tensing up all your muscles, which is a natural reaction when you see that you are about to get hit, can actually be the cause of a large number of injuries sustained in accidents...Or so I'm told.


Unfortunately, though, I don't think there is any way to get hammered (pun intended) fast enough to help.

SoonerInKCMO
9/3/2008, 01:50 PM
My question: does this make sense, scientifically speaking?

No.

More energy = more pain.


Unless... your car is so powerful that you can accelerate to a speed where relativistic effects on your car's mass have to be considered. Like, if you were able to get up to about 0.98c and your mass was comparable to a semi's.

Tulsa_Fireman
9/3/2008, 01:56 PM
To put into layman's terms...

You're screwed.

Hope to all that's holy the front end of your highly efficient, fiberglass coated 4 banger doesn't look like a ramp you could jump a motorcycle on. Because I can promise you, the car that's quickly approaching will do just that. And no crumple zones or breakaway draivetrains will save you.

SoonerInKCMO
9/3/2008, 02:02 PM
Yeah, as long as you have the big-*** SUV killing machine... **** the other guy.

bonkuba
9/3/2008, 02:04 PM
Okay, here's what I was thinking in my liberal arts brain that is seasoned with some basic aerodynamics and bombing theory and practice.

If you could speed up and do better than the other guy, than theoretically, if you could go fast enough in the opposite vector, a bullet fired at you couldn't hurt you.

OK.....now my head hurts :D

Tulsa_Fireman
9/3/2008, 02:08 PM
Yeah, as long as you have the big-*** SUV killing machine... **** the other guy.

Hmmmm...

More mass between me and the guy that failed at the rules of the road, swerving into my lane of traffic to put us both in harm's way.

Hmmmm...

A better chance at survival so I can continue to feed my family through the wages I earn. A better chance at survival for the family I love, too.

Hmmmm...

Lower gas mileage versus the potential safety of the very reason for my existence. Giant Dodge Ram killing machine. Yeah, you hit it dead on (pun intended).

**** the other guy. He shoulda took a nap.

SoonerInKCMO
9/3/2008, 02:17 PM
And if the other guy - the one that screwed up and came into your lane - is driving an F-450 with a bed full of gravel? I guess you'll just have to drive a cement mixer... unless he has a semi.... then you could get a bigger semi. Where does it end?

yermom
9/3/2008, 02:20 PM
that's kinda where i was going with the brick wall thing

OU4LIFE
9/3/2008, 02:34 PM
Not a physical guy.

I hadn't noticed.

Tulsa_Fireman
9/3/2008, 02:41 PM
And if the other guy - the one that screwed up and came into your lane - is driving an F-450 with a bed full of gravel? I guess you'll just have to drive a cement mixer... unless he has a semi.... then you could get a bigger semi. Where does it end?

So your point is I should put my family in harm's way by driving a bundle of plastic and fiberglass so I won't be caught in the trap of oneupsmanship?

That is retarded. In fact, that is beyond retarded.

It's not an arms race, it's the fact that I've laid these two calloused hands on the very product of this thread. I've cradled broken limbs, cupped remnants of the human form, and have seen with my very own two eyes the product of cafe standards and high efficiency vehicles.

The results are not pretty. Not in terms of the bottom line product of our nation's highways and her cruel demeanor.

So I will put more steel, more mass, more vehicle between myself and the rest of those on the road. I will spend what it takes to fuel it, I will negotiate the inconveniences of driving a larger vehicle. I will pay the payment, and I will smile, every time I turn and see the beautiful blonde Sooner girl sitting in the passenger seat and my dearest daughter in the back, knowing they're safer than what they'd be were I getting 35+ miles per gallon.

Knowing that should the unspeakable happen, sorry about that, Mr. Other Driver. But mine come first, and it's not the product of some assumed ramping of conflict or pursuit of bigger, better, harder, and armored.

It's a product of the love I have of my family. And if you can't understand that, then you never will.

Sooner Eclipse
9/3/2008, 02:42 PM
Context of our discussion: Imagine a scenario in which you're traveling at highway speed and all of a sudden a guy in the opposite lane who fell asleep careens into your lane. You can't avoid a collision because there's no where to go on your right (no shoulder, trees), and you don't want to do anything sudden to your left because he might wake-up and overcorrect or you could lose control or both. Slamming on brakes doesn't take you out of harms way even if you could stop after laying down 100 feet of skid marks. Thus, according to this guy, just floorboard it.

Imagine both vehicles are of comparable size and weight.

My question: does this make sense, scientifically speaking? It seems to me it would take cajones the size of pomegranites even if it does.

No it doesnt make sense. Use M's formula. Any advantage you gain by having the greater velocity is going to more than offset by the larger amount of kinetic energy being being absorbed by the vehicles and therefore the occupants of those vehicles. The greater the speed, the more violent the impact and the less likely you are to survive.

Investigating this type of thing is actually part of my job. I work as field engineer for Volvo. Its what we do.

olevetonahill
9/3/2008, 02:46 PM
Best as I can figure it Just makes it so The Tulsa Fireman , Doesn't have to be in a Hurry to cut yer Carcase out of the Mangled POS .

Oldnslo
9/3/2008, 03:23 PM
No it doesnt make sense. Use M's formula. Any advantage you gain by having the greater velocity is going to more than offset by the larger amount of kinetic energy being being absorbed by the vehicles and therefore the occupants of those vehicles. The greater the speed, the more violent the impact and the less likely you are to survive.

Investigating this type of thing is actually part of my job. I work as field engineer for Volvo. Its what we do.

In my experience, M and Eclipse are on target.

About the only thing you can do, in the instant of last resort, is to swerve so that you don't have a head-on. Any angle of deflection is better than a 100% head-on collision.

Speeding up is teh dum.

yermom
9/3/2008, 03:24 PM
So your point is I should put my family in harm's way by driving a bundle of plastic and fiberglass so I won't be caught in the trap of oneupsmanship?

That is retarded. In fact, that is beyond retarded.

It's not an arms race, it's the fact that I've laid these two calloused hands on the very product of this thread. I've cradled broken limbs, cupped remnants of the human form, and have seen with my very own two eyes the product of cafe standards and high efficiency vehicles.

The results are not pretty. Not in terms of the bottom line product of our nation's highways and her cruel demeanor.

So I will put more steel, more mass, more vehicle between myself and the rest of those on the road. I will spend what it takes to fuel it, I will negotiate the inconveniences of driving a larger vehicle. I will pay the payment, and I will smile, every time I turn and see the beautiful blonde Sooner girl sitting in the passenger seat and my dearest daughter in the back, knowing they're safer than what they'd be were I getting 35+ miles per gallon.

Knowing that should the unspeakable happen, sorry about that, Mr. Other Driver. But mine come first, and it's not the product of some assumed ramping of conflict or pursuit of bigger, better, harder, and armored.

It's a product of the love I have of my family. And if you can't understand that, then you never will.

well, and when i crush you and yours in my semi, i won't feel bad :D

Chuck Bao
9/3/2008, 03:55 PM
I know nothing of physics.

I ride a bike. So in any head-on collision, I'd be toast – airborne or runover toast.

My only hope is to speed up and try to swerve. It is counter-intuitive, but I would have much greater control of the bike when speeding up than when slowing down.

A car should be the same. As others have mentioned, even a slight angle would help improve chances, right?

So, step on the gas.

GottaHavePride
9/3/2008, 07:21 PM
Context of our discussion: Imagine a scenario in which you're traveling at highway speed and all of a sudden a guy in the opposite lane who fell asleep careens into your lane. You can't avoid a collision because there's no where to go on your right (no shoulder, trees), and you don't want to do anything sudden to your left because he might wake-up and overcorrect or you could lose control or both. Slamming on brakes doesn't take you out of harms way even if you could stop after laying down 100 feet of skid marks. Thus, according to this guy, just floorboard it.

Imagine both vehicles are of comparable size and weight.

My question: does this make sense, scientifically speaking? It seems to me it would take cajones the size of pomegranites even if it does.

So what he's saying is IF you spot it happening early enough, the best way to dodge is to speed up so that by the time the driver crosses into your lane, you're already past him moving away. Or so that instead of a head-on collision he maybe clips your rear quarterpanel, so you skid for a while, maybe even spin, but it's better than a head-on collision.

That's got nothing to do with speed and EVERYthing to do with 1) how early you spot the imminent accident and 2) positioning your car to take the least direct impact possible.

BigRedJed
9/3/2008, 07:37 PM
That makes sense.

Sooner Eclipse
9/3/2008, 08:52 PM
A "certified accident reconstructionist" and OHP trooper told me yesterday that the best thing to do if you are confronted with an unavoidable head-on collision is to speed up. Something about the car with the greatest velocity does better in such crashes.

I never took physics, but it seems counterintuitive to me.

what say you?

:pop:

Jed, I think you and GHP missed the part about it being an unavoidable head on collision.

The OHP guy is just wrong.

BudSooner
9/3/2008, 09:23 PM
Just wash yer balls, at least when they use tweezers to find whats left of ya they can use yer scrote to find out who and how big of a dumbass ya are.

Or something like that.

LePetomaine
9/4/2008, 09:07 AM
My question: does this make sense, scientifically speaking? It seems to me it would take cajones the size of pomegranites even if it does.


No, it does not make sense, and in fact seems somewhat irresponsible. A large part of analysing how a car functions in a crash sequence is the calculation of the change in velocity. Essentially, the reconstructionist can take the post-crash evidence (skid marks, scrape marks, crush measurements of the vehicles, etc.) and determine an estimated speed at the time of collision. Then he can use physics calculations to estimate the change in velocity of the vehicle, which is the equivalent of the car striking a stationary barrier (like we see in the crash test dummy videos). Example: It appears that vehicle A was travelling at 68 mph, and given all the data that we have (vehicle size, shape, weight, etc.) this gives us a change in velocity of 39 -- the same as if the car hit a concrete barrier, head-on, at 39 mph.

So, the end result is this: a car crash is not a jousting contest. If we have identical cars on a flat surface with a head-on impact (no off-set at all), and I increase my speed, I may well "out crash" the other guy; but I have also increased the change in velocity that my body will have to endure in the crash sequence. That could mean the difference between a few more days in the ICU or a long nap 6 feet under.

Okla-homey
9/4/2008, 09:23 AM
So, the end result is this: a car crash is not a jousting contest. If we have identical cars on a flat surface with a head-on impact (no off-set at all), and I increase my speed, I may well "out crash" the other guy; but I have also increased the change in velocity that my body will have to endure in the crash sequence. That could mean the difference between a few more days in the ICU or a long nap 6 feet under.


eggselent...works for me.

soonerbrat
9/4/2008, 10:46 AM
eggselent...works for me.


sounds like he knows what he's talking about. or she. can't really tell.

LePetomaine
9/4/2008, 11:06 AM
its a he

I'm no expert, but I've defended many automotive products liability cases. The computer simulations that are now available for crash analysis are pretty amazing. Unfortunately, the crashes that warrant that kind of review are very, very bad.

That said, accelerating into a crash makes no sense. Find an angle and let the energy/impact move somewhere other than into the bodies in the car.