> It is a vanishingly small number of scenarios where you are keeping pace with a car next to you and you're not in the wrong.
I think it really depends on where/when you're driving. I find this to be a common scenario on interstates during rush hour:
I'm in the right lane, doing approximately the speed limit. There is a safe distance between me and the cars in front and back of me, but only just. If many more cars enter the road, traffic would need to slow down to maintain safe distances. In the left lane is the same situation, except they're averaging about 1 or 2 mph faster. In this situation, there are cars in the left lane passing very slowly, spending a lot of time alongside me. I could slow down below the speed limit every time a car passed on the left, to reduce reduce that loiter time. But this would make my driving less predictable to the drivers behind me (and waste a lot of mileage too...)
So normally, when the other cars are my size, I maintain my present course and speed, driving as predictably as possible to help the other drivers anticipate my course. Changing position in traffic is inherently risky, so I avoid making changes unless doing so is necessary to avoid something I judge to be more dangerous than the average. If a truck passes me on the left, I'll slow down to make the passing faster even if that means a car behind me has to brake. But if in that moment I judge the guy behind me to be even more dangerous, then maybe I won't. It's the kind of decision that needs to be made on the spot in a case-by-case basis. On interstates that are flowing fast near capacity, you need to be constantly evaluating the relative threat of the traffic around you.
I think if you're in the left lane only going 1 mph faster than the cars in the right lane, especially in traffic, something is wrong. Especially on interstates where lanes are typically wide and the road relatively straight, and in good weather & visibility, if you have any appreciable amount of traffic on the road it's much better to go 5-10 over to pass then get over to the right and go back down to the speed of the right lane than it is to be in the left lane holding up a line of traffic while you take 5 minutes to pass one semi.
I think it really depends on where/when you're driving. I find this to be a common scenario on interstates during rush hour:
I'm in the right lane, doing approximately the speed limit. There is a safe distance between me and the cars in front and back of me, but only just. If many more cars enter the road, traffic would need to slow down to maintain safe distances. In the left lane is the same situation, except they're averaging about 1 or 2 mph faster. In this situation, there are cars in the left lane passing very slowly, spending a lot of time alongside me. I could slow down below the speed limit every time a car passed on the left, to reduce reduce that loiter time. But this would make my driving less predictable to the drivers behind me (and waste a lot of mileage too...)
So normally, when the other cars are my size, I maintain my present course and speed, driving as predictably as possible to help the other drivers anticipate my course. Changing position in traffic is inherently risky, so I avoid making changes unless doing so is necessary to avoid something I judge to be more dangerous than the average. If a truck passes me on the left, I'll slow down to make the passing faster even if that means a car behind me has to brake. But if in that moment I judge the guy behind me to be even more dangerous, then maybe I won't. It's the kind of decision that needs to be made on the spot in a case-by-case basis. On interstates that are flowing fast near capacity, you need to be constantly evaluating the relative threat of the traffic around you.