Traveling the highways and byways of this great land, interstate driving can be cumbersome with "slow" drivers in the passing lanes. Are you with me here? And then let's not forget the 18-Wheelers who "decide" in pairs to start a convoy to slow down the traffic on their own. Sometimes it's when there are the silly ones weaving in and out of traffic at 90mph (especially on mountainous roads), and, I believe, those smart truck drivers can't take it any longer then "fix" all the drivers, not the ones causing the distress with an intentional slow-down.
I'm hoping it's all done for the safety of the travelers no matter the size of the vehicle.