For the operation of rear and side dump semi trailer, Make sure the truck head is straight with semi trailer,

being in a line, and must park on the flat ground!

Com: Semi truck : What was "he" thinking? What was the other idiot thinking also?

Standing up there. Not sure it was clear the guy was cut in half. A lot of comments here stating that but nothing here that shows this.

Maybe the other guy yelled and he got to the other side of the cab?

And wouldn't it have crushed him...and not severed anything?

Either way, some people just don't take physics seriously enough.

These trailers are long, carry a lot of weight, and lift that weight far off the ground.

There isn't much room for error here...

even if the trailer appears flat/horizontal,

it only takes inches when it's raised to create a problem.