[Swizec]

I've always assumed you can press the brake post fact to prevent rolling into an intersection, which I assumed was better than absorbing a lot of G-force.

Fundamentally, I think, if the impact is too strong for you to be able to react in time to brake before rolling too far, you would have rolled into the intersection despite holding the brake. Except it would be a skid not a roll.

I could be wrong, obviously.

[crottypeter]

Your vehicle will accelerate less (fewer Gs) if your brakes are on.

[Swizec]

The energy is still going to have to go somewhere.

Some of it will go into the crumple zones, the rest will go into burning rubber and throwing passengers against their restraints.

The question is whether a person is better able to withstand being pushed from the back with rapid acceleration, or absorbing the energy of a collision.

I do not have an answer, but I'm very interested where I could find one.

You mention whiplash in another comment. Wouldn't you avoid most whiplash with a properly configured headrest?

[crottypeter]

Yes, that is what the crumple zones are for!

Not sure what you mean by this: > pushed from the back with rapid acceleration, or absorbing the energy of a collision. The occupants don't have to absorb the impact if the crumple zones take it!

I guess decent seats will do a lot to protect the occupants. A few years back I was a rear-seat-passenger in one of these https://upload.wikimedia.org/wikipedia/commons/5/50/Nissan_M... when it was rear-ended. Luckily our driver WAS on the brake and didn't go forward into the cars in front - unlike the car behind us and the car behind them and the car behind them! (I forget exactly how many cars were involved but it needn't have been as many).

[donkeyd]

It's not about impact being strong. The surprise of the impact will severely slow down your reaction. By the time you've reacted, it's probably too late.