The rule for the leftmost lane (highway) is that you must not block for other drivers. It is in the rule book (at least in my country). That mean in very clear terms that if you can't do the overtaking in a timely fashion without blocking other drivers, then you should not enter the left lane.

If there is one thing that tend to cause conflict and trigger dangerous situations in traffic, it is when someone driving at 0.001% faster than the next car enter left lane while maintaining the exact same speed, basically matching the speed on the right. That is just as illegal as speeding.

> That mean in very clear terms that if you can't do the overtaking in a timely fashion without blocking other drivers, then you should not enter the left lane.

And then there are the drivers who are in the centre/right lane who, when you try to pass on their left, speed up to try to prevent you from passing them.

I'm often on highways were the left lane, for many miles, is the only one without potholes and broken road.

Then when there's another person behind you, get over in the right and let them pass.

If everybody left it, it wouldn't be going 5+ over limit and then it could serve the people who are serious about breaking the law and go big. ... Oh, wait...