giving them room is not the issue here. but needless to say that this is a good idea
"drive a truck so you know what its like" yeah i will be off spending my hard earned on a few bog laps in a truck. what a laugh.

The whole idea of tying down a load properly is that it is then restrained in such a way that i DOES NOT MOVE. so if the load moves after it is restrained then it is NOT TIED DOWN PROPERLY and there are laws that govern this as well.

the only exception to this tied down thing is a grain truck that when stopping as hard as it can without locking up the wheels is allowed to experience a 4 tonne shift of grain per trailer to the front of the trailer (based on 40 foot standard trailer loaded to 42 tonne)

trucks are designed to be able to stop quickly in emergency situations as they have brakes on each wheel or each axle depending on design.
if you find it difficult to stop go fucking service your truck

and for fucks sake your driving a heavy vehicle that does not react quickly so dont fucking tailgate a car because it will stop quicker than you.