Question

Why should you stay out of the open space to the right of a semi-tractor-trailer?

Answer 1

because you never know where the semi tractor is going to go . 

Answer 2

Your Answer Is...

You should stay out because it may not see you, turn to the right lane, and crush you because you'd be in the middle of it and it'd knock you off the road.

Glad I Could Help, And Good Luck!