Imagine crashing on the motorway in these circumstances.
1) Driving a 2020 car driven at 70mph.
2) Driving a 2010 car at 60mph.
3) Driving a 2000 car at 50mph.
Assuming the circumstances of the crash are identical, apart from the speed, and later car have the latest safety features, which is safest? And why?
2020 car, is going to be built to sustain much more high energy impacts than the older cars. 2010 would still be a fairly safe car by many standards however if you consider the difference between 60 - 70mph that is still a pretty high energy crash, and I think the car would still be the deciding factor rather than just the speed.
I remember cars in the 2000 going through NCAP which was only introduced in the 90s, so cars passing NCAP back then, wouldn't stand a hope in hells chance these days.
One big consideration is the mechanism of the accident, what they hit, where they hit it position of the car (ie side on, front on etc) and this will have a far bigger bearing on the survivability of the accident than just the age or speed alone.
another thing to consider is the car. ie a 2010 S-class merc is probably always going to be safe than a 2020 budget economy car.
Back in the early 2000s the company I worked for at the time, in the motor trade sold a Saxo to a youngster who wrapped it wound the front of a Mercedes on his way home. The Mercedes driver was totally unharmed, I think it was a 2 or 3 year old Saxo at the time so not an "old" car, he and his passenger were killed instantly and we panicked when he heard there had been a death and pulled all the maintenance records on the car- turns out he was just driving like a bell end, overtaking on a single track road with oncoming traffic and not enough power to complete the maneuver in time
