They are governed vehicles. Meaning they are both at top speed, the one being passed should let off the throttle and let the passing semi by.It seems like some of today's truckers are oblivious or selfish... they set the cruise and couldn't care less how it affects others.
What other answer is there for how often you run into two semis going the same speed down the highway side by side for mile after mile, with a long line of cars stewing behind them?
Symptom of overall culture I guess? :;:huh