What happened here?

Well, there is this video of a jersey barrier keeping a crashing tractor trailer from causing more damage than it could have.

It's all about the angle. A glancing blow will likely deflect a truck while a more direct strike will cause a truck to stop due to severe damage.

Trucks that fall from bridges usually do so because of the parallel angle the truck is to the jersey barrier, the speed, and whether the trailer is top-heavy.

 

Possible medical issues (cardiac arrest/heart attack) maybe?

 

Had his foot on dash scrolling thu toktik foot slipped off while scratching balls . Idk , maybe.

 

On that bridge???
If it was an Amazon bobtail that might be plausible but going on that bridge no matter which direction it’s always pucker time. And that was before they started repairs on it!