https://www.youtube.com/watch?v=kpKqzbwKXdU

very horrific indeed.

the accident could have been avoided if the occupants in car had their seat belts striped and the driver wasn't over-speeding.

Let's assume they had seat belts on

Let's assume they were over speeding also

The accident would still have happened because the driver failed to take evasive action after getting himself in a bind

He did not swerve into his proper lane or swerve into the left road shoulder or the right road shoulder until the mess he put himself in cleared.

All the driver knew was how to drive fast and not how to drive safe.

Finally, if you don't have clearance or allowance, it is foolish to attempt an overtake especially on that kind of road.

So in short

even if he had no seatbelts
even if he overspeed

But he exercised the precaution of ensuring he had clearance or allowance to overtake

there would have been no incident.