Description of what happens when you hit a tree
 

I remember a couple of years ago I read a description somewhere on the internet aboput what happens to your body and the car when you hit a tree at 50mph. It was called death in less than a second. I can't seam to be able to find it, does anyone have a copy or know on what site I can find it.

I would also like some video fottage of some crash test dumbies like in the euroncap trials.

Accident Kinematics
 

Try doing a google search on "Accident Kinematics"

You should find the 3 phases (Impacts) of a road accident listed in there
i.e Car strikes Tree
Driver strikes steering wheel
Internal organs strike chest cavity and liquify.

:rolleyes:

http://www.applied-kinematics.com/ak/onlinetools.asp

Some quite graphic photos and video footage

:( Not nice at all.

hmmm... istr reading similar too.... yet rally cars bounce off trees at far greater speed and all the drivers complain about is they've missed a chance to score points :rolleyes:
OK, roll cage makes the car much stronger, but that has to increase the decelleration!

One of the indycar crashes in recent years recorded a peak of 150g, and the driver lived.

Internal organs liquefied!? No doubt these things are true in certain worst case scenarios, but not quite as cut and dried as it seems perhaps. Seems like a deliberate attempt to shock.

Not an attempt to shock at all. Been there, seen it all. Relatively low speed collision. No or little visible bodily (person) external damage. Very peacefull looking young female, involved in a head on collision with a rather large tree.

Police concluded after fatal accident inquiry that road speeds were not excessive 40-50 mph

Coroners verdict was death due to massive internal hemmoraging of internal organs. Lung and digestive tract tissue being compressed by such pressure and kinetic forces as to break down the tissue instantaneously. (or Liquification).

its on one of the speed camera sites

i believe it was posted by a police officer

good read but irrelevant

if it happens your dead anyway.. what differeance does .50 of a second make??

(tounge in cheek)

Mart

Trees usually win.
If you hit another car, crumple zones on both cars progressively collapse, and you decelerate quickly, but over a period of time. The energy of crash is shared out between cars, and is transfered over this period of time.
If you hit a (big) tree, the deceleration is much more rapid ( as the tree doesn't crumple). Because of this most of your body stops, but some bits, especially the heart and liver continue to hurtle forwards. The heart is attached to the aorta ( the main artery) and if it moves fast/far enough will tear the aorta. There is a thinbit of ligamenty type material in between the two halves of the liver, and this can act like a cheesewire as the liver goes forwards.

My version is more accurate I feel
 

This is a slow motion, split second reconstruction of what happens when a car traveling at 55 mph, crashes into a solid, immovable tree;

1/10th OF A SECOND: The front bumper and chromium radiator grille collapse. Slivers of steel penetrate the tree to depths of one and a half inches and more.

In the same tenth of a second: There is a noise within the vehicle cabin 'F'

2/10th : The bonnet crumples as it rises, smashing into the windscreen. Spinning rear wheels leave the ground. The radiator disintegrates. The wings come into contact with the tree, forcing the rear pads to splay out over the front door.

In the same second tenth of a second: The heavy structural members of the car begin to act as a brake on the terrific forward momentum of the body, but the drivers body continues to move forward at the vehicles original speed. This means of force of 10 times gravity his body weight 3200. His legs, ramrod-straight, snap at the knee joint.

3/10th : The driver's body is now off the seat, torso upright, broken knees pressing against the dashboard. The plastic and steel frame of the steering wheel begins to bend under his terrible death grip. His head is now near the sun visor, his chest above the steering column.

In the same tenth of a second: There is another noise within the vehicle cabin 'U'

4/10th : The cars front 24 inches have been completely demolished, but the rear end is still traveling at an estimated speed of 35 miles per hour. The driver's body is still traveling at 55 MPH. The engine block crushes into the tree. The rear of the car, like a bucking horse, rises high enough to scrape bark of low branches.

5/10th : The driver's fear frozen hands bend the steering column into an almost vertical position. The force of gravity impales him on the steering column. Jagged steel punctures lung and intercostal arteries. Blood spurts into the lung.

In the same tenth of a second: There is another noise within the vehicle cabin 'C'

6/10th : So great is the force of impact that the driver's feet are ripped from his tightly laced shoes. The brake pedal sheers at the floorboards. The chassis bends in the middle. The driver's head smashes into the windscreen. The rear of the car begins its downward fall, with spinning wheels digging into the ground.

In the same tenth of a second: There is another noise within the vehicle cabin 'K'

7/10th : The entire, writhing body of the car is forced out of shape. Hinges tear. Doors spring open. In one last convulsion the seat rams forward, pinning the driver against the cruel steel of the steering column. Blood leaps from his mouth. Shock has frozen his heart. He is now dead.

You sure it wasn't F... U... C... K..........F...U... E... L..........S... U... R....

*DEAD*

:D

Possibly :D, joking apart I left the my lane of the road at over 80mph - it could have been me :eek::(

So its all over in 7/10ths of a second. Doubt you'd be complaining much.

I think one of the crucial reasons as to why race/rally driver survive such heavy impacts is puely down to the seats and seatbelts

3 point belts just don't hold you in the seat...thus the need for airbags etc.

Now if we all had 5 point centre coupled harnesses we would be alot safer...but we'd still be killed as our necks would break - so we would need to wear neck braces and helmets too.


Also - but to a much smaller extent...the chassis of a race/rally car is far more rigid and stuffer in the areas needed...that being the bulkhead, so your less likely to be injured by the pedals and steering column.

The problem with hitting something like trees is that it concentrates so much force on such a small area, and more often than not the tree misses the main box sections of the chassis (the bits that the subframe/engine/suspention bolt to), so more deformation occrus with much less reduction of speed. If the car did hit a main chassis member/section it would just bounce off it (as it would be an off-centre impact) and far less damage would result, although the occupant will still be flug round like a rag doll bouncing off windows, A-pillars, steering wheel, airbags etc.

Also the fact that most cars chassis like to bend right below where your sitting pushing your head out the front screen is obviously a very bad thing. Race/rally cars don't do that thanks to a nice hefty roll cage.

Food for thought when you decide to go for a blast round the B-roads.

I'd like to floor another possible reason: Their bodys are built to withstand more of an impact due to consistantly being subjected to forces moving in all directions and some impact forces (landing jumps, etc). The reason I say that is that the blackbelts at my martial arts class can peform break falls for 6-7 in the air landing on their back and side from such heights with no pain. Even though the lower grades may know the correct technique to distribute the energy they haven't had the years of 'falling' to allow the muscle around all their internal organs to develop and thereby get hurt. I hope that made sense, I can possibly clarify if required but I would suggest that joe rally driver has far better muscle support around his organs than joe street driver.

....but less flab to cushion the impact :D

Cheers guys that is exactly what I was looking for.

Has anybody got any suggestions for get crash test footage?

I've got a great wee video clip of a bloke rolling has car after he fell asleep, no seat belt on either.

give me a shout and i'll mail you

take a look here too

http://www.nhtsa.dot.gov/kids/research/crashtest/ncap/

and here

http://www.autosafety.org/crashlounge2.php

I put a SAAB 99 through two fir trees at about 50mph when i was 16, they were about 10" diameter snapped them both off at ground level, destroyed the front of the SAAB but absolutely no cabin intrusion, i think i would have been dead in 90% of other cars. I think it helped a lot that i had time to think as the car slid "right, bend your elbows, bend your legs, relax....." :eek: as it was inevitable that she was gonna hit them....

Ya live and learn sometimes.

Owain :)

I had a drunk hit me head on at over 100 mph, and lived, only just mind, the combined speeds of the guy that hit me and my van was the police say over 170mph head on, I guess luck was on my side that night, but as someone said it's over in a flash.
Cheers
Colin

I'm not trying to negate the what's said, or the warning; I plan to avoid trees as much as posisble :) However... the less the car deforms, the shorter the period over which the stop takes place, so the more severe the deceleration... Harnesses etc only increase this effect... so I really don't understand how in one circumstance organs liquefy hitting a tree at 50, but do it in a differnent sort of car at more speed one can walk away?? Anyone explain?