And on the issue of vehicle weight being safer....
Many years ago now but the math on this is something like (Force of Car 1 prior to impact) + (Force of Car 2 prior to impact) =
Total Impact Force.
From this Total Impact Force is deducted an amount due to the absorption of energy by car frame/safety features. In a car on car impact scenario, the structural safety features e.g. crumple zones, high strength bars etc found on a single car help reduce the total impact force thereby helping passengers in
BOTH cars.
The remainder of the force is then split between the two cars in a proportion depending on their weight.
( Note that if everyone were to drive slower and also drive lighter cars then real world collisions would involve less Total Impact Force
)
In the real world this remaining force normally translates to a fast deceleration of the cars, even a possible change of traveling direction. It is this fast deceleration that causes the damage to the head, brain, neck. A heavier car takes less of the force and deceleration would be less. (i think: A car weighing 2 tonnes in a collision with car weighing 1 tonne. Twice as much of the remaining force will be applied to the 1 tonne car would take versus the 2 tonne car)
Therefore IMO a heavier than average car is generally safer on the road in collisions vs average weight cars.
ALSO I THINK:
Lighter cars are safer in collisions vs solid immovable objects such as walls, rocks (less mass involved).
Other factors including airbags, interior space (distance from impact to passenger, larger being safer), relative height of impact zones (head height being worse) can make a difference. A light, cramped car is not as safe in a car-on-car impact as a heavy spacious car.