Astraist wrote:
That's good for pedestrians. But once you put an SUV or proper 4X4 in a collision with another, smaller, vehicle, more of the collision's overall energy will be absorbed in the opposite vehicle.
No it won't - this statement violates Newtons 3rd law of motion which tells us that any force that is imparted by a body affects the source equally.
The total energy output of both vehicles combined is released into both vehicles. The relative distribution of energy between them depends on the individual action and reaction force vectors, which are modified in modern vehicles by the impact absorption and distribution mechanisms built into them, and how the vehicles interact with their environment in the immediate aftermath.
In any event it is desirable that the energy is imparted into the vehicle and away from the occupants. A major element of the passenger safety cell concept is to direct energy into the vehicle's extremities and around the passenger cell rather than into the passengers.
The hypothesis that a small vehicle comes off worse in a collision has nothing to do with the larger vehicle imparting more energy and everything to do with the smaller vehicle being less strong and thus less able to absorb and redistribute the impact energies.
But event that view is also badly out of date as modern cars are considerable stronger and better at absorbing and redistributing impact as can be seen in this video where a small family car destroys the front of a much heavier and supposedly "safer" but also older Volvo:
it's not the size of the vehicle that matters, it's how it is all put together....
I spent close to 8 years investigating accidents, a large part of which involved studying and developing computer simulation systems to model and understand how both vehicles and people really behaved in collisions, and one of the first things you learn in that game is that everything that you think you know about collisions is completely and utterly flat out wrong. An experience that those motor engineers who work in this area that I spoke to confirmed that they had all shared.
Fortunately motor engineers prefer to use real data, tests and simulations to driver their work and not their supposed everyday "common sense". Had the industry relied on the latter we may well be still seeing the level of carnage that we saw in the 1970s and 80s albeit scaled up to match traffic growth.
If only the road safety "experts" that infest local and national roads authorities and the likes of BRAKE would learn the same thing casualties may well have been driven even closer to 0. But that is another story for another thread.
Though sometimes common sense can be right, You'd not want to be hit by a modern Volvo XC90:
