4x4 Vehicle safety

It’s been very wet round here recently with some areas experiencing their worst floods for over sixty years. As you might expect there are tales of selfless effort and other tales of total selfishness. On the one hand there were drivers with large 4wd vehicles who went out of their way to help others and then there were the few who ignored the needs of others and drove their vehicles with no regard for anyone or anything.

This got me thinking about the general safety of 4wd vehicles and I came to what I think is an interesting conclusion.

4wd vehicles are inherently less safe than 2wd vehicles.

Ignoring all the psychobabble about feeling safer in a larger vehicle which I don’t understand, this is my theory.

Stopping a vehicle from any speed requires that the energy stored by getting the vehicle up to that speed must be expended. The amount of stored energy is determined by the speed of the vehicle and its weight.

For any given speed, a heavier vehicle will have to get rid of more energy than a lighter vehicle. The energy goes into heating up the brakes, tyres and even the road surface and also in a certain amount of noise in some cases.

4wd and 2wd vehicles have the same number of brakes, so there is no difference there. The difference between the two types is the number of wheels that take power from the engine, either 2 or 4. To take power from the engine to an extras pair of wheel requires at least one, probably two, extra differentials and their drive shafts. These are heavy pieces of kit and add quite a lot of weight.

So we now have a heavier vehicle which is not as easy to stop, but the same number of brakes. On top of this the 4wd vehicle is capable of building up speed in conditions that would defeat 2wd. So we have the situation that a 4wd vehicle is easier to drive into trouble and then less able to stop.

2wd or 4wd, drive carefully out there.