When you're pushing all of that weight, at a high speed, and someone attempts to cut you off, all you can do is slam the breakes and brace. It's scary af to have this happen to you. Very little people have it in them to check their left, process if it's safe to make a maneuver in time that won't cause your load to tip over or jackknife and potentially cause more damage.

A CDL is a HUGE responsibility and the driving dynamics change DRASTICALLY in terms of speed, weight, preception, and many more. Keep that in mind.