I've just been watching a Jackie Chan movie where they jump from a train onto grass.
If the train is moving at 100mph would they hit the ground at 100mph and therefore kill or maim themselves?
My 1 brain cell says that would happen.
They'd slow down a fair bit die to windblast etc but ywah theyd hit the ground like 70+mph and have severe injuries
If they were wearing a learher one piece motorcycle suit they'd stand a decent chance though if it was smooth tarmac and rhey could slide.
The roll though is the worst thing rolling makes you flail whoch slams your limbs into the ground at high speed over and over breaking all your bones.
Ideally you just slide in one position oh and hitting any solid objecy would be instant game over/massive injury
Rember the road race rider last year who came off an slid into a drop kerb
Best helmet, leathers and airbags monthy can buy but headbutting a curb is a broken neck