[jrootabega]

In my experience, anywhere there is heavy semi truck traffic will have significant problems once there are enough cars around ("enough" being far less than it should be). 2 lanes, 3 lanes, 4 lanes, hills, it's all bad. But yeah, only 2 lanes per direction makes it comically awful. Happens on sections of I-81 too.

I think the specific pattern you're talking about happens because when a truck is passing slowly but infrequently, it makes some sense to be polite and line up behind it. When trucks are passing so frequently, and so incredibly slowly, being polite is useless. There needs to be a zipper merge happening behind the truck being passed. But the left lane people feel they've paid their dues by waiting in line, and half the right lane people don't even care. The right lane people also stay so close to the truck in front that they can't safely merge left at highway speeds anyway. People also tend to not fill back in to the right lane between truck passes. I'm not sure that would even help, but it does make people who do seem like cheaters to the people who refuse to.