More Debates over 4wd

A well researched rebuttal of the current anti 4wd myths at last ! Excellent !

Hi Folks,

The article says "A heavy 4WD will do exactly the same amount of damage as a large sedan, van, mini bus or people mover of the same weight. Its just simple physics about how much energy has to be dissipated in the crash."

The first part of this is rubbish because the second part is ignoring the time period over which the energy is dissipated. Having a large crumple zone causes the decelleration in an accident to be reduced and this in turn reduces the injuries in accidents because it reduces the forces achieved.

Remember school physics? The author is talking about kinetic energy.
(k = (u^2) / 2) In fact if you brake gently from 100kph and come to rest you dissipate the same kinetic energy as if you stopped by hitting a brick wall. Same energy, but different damage. In the case of braking, the kinetic energy is converted to heat energy in the brakes.

The thing that determines damage is not the energy dissipated, rather it's the force generated. (F = ma) The longer the vehicle spends crumpling and decellerating, the lower the force that is generated.

My Troopy's chassis ain't likely to crumple much in a head-on accident and I am sure it would do much more damage to an opposing car than a similar weight sedan with a good crumple zone designed to minimise accident forces.

I think we have an obligation to other road users to understand some of the characteristcs of our vehicles and to drive them accordingly. It's fine to defend our cars from the attacks people love to make on them, but let's not accept wrong arguments just because they support our case.

Cheers Frank.