The heavier the car the more kinetic energy it has when involved in a collision. This energy must be disposed of either through friction with the road surface (lock the brakes), or by deforming body panels (when you hit something).

On almost any surface a heavier vehicle will take longer to stop than a lighter one, the contact patches for the tires being very similar in area. Once the tires are at their limit for grip, because you've stomped on the brakes, the heavier car will always take longer to stop.

On a slippery surface the heavier vehicle is at a much bigger disadvantage, it has more momentum acting against the reduced friction with the road. When it comes to traction to get going the diesel has low end torque acting against it, as lots of torque at low RPMs is the last thing you need when trying to start moving on a slippery surface.

All of the above is yet another reason why it is worrying that we have increased numbers of big SUVs on the road. If we follow the reasoning that you need a big SUV to be safe in a crash, what do you do when everyone has a big SUV, drive a Semi?

My own feeling is that avoidance is better than survival, and I believe a light, modern, vehicle is more likely to be able to avoid a crash than an old, heavier one. On a modern vehicle all the steering and suspension components will be in better condition than your 300D, the brakes will be better, the crumple zones better designed, etc, etc.

Kevin

__________________
'85 300SD