Earlier quoted context omitted.
It's a shame this is getting downvoted because it's true. In any level of traffic except stop-and-go--and even then to a large extent--you should be doing everything within your power to either pass the cars on your right, and/or move over to let cars pass you on the left. 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. This isn't just at hi…
That's not the same everywhere in the world though, and even in places where it is strictly passing on the left (or on the right in the UK, Japan and a few other places) 'keep your lane' tends to be the rule if the right hand lane is also moving at the speed limit (so you can't legally pass). That way the carrying capacity of the road is higher. But when traffic is less dense 'station keeping' should be avoided at al…
Why are you in the lefter lane if you can't pass?
I've been in rush hour (where keep-to-the-right-unless-passing is very strictly enforced) in bumper-to-bumper traffic and the left two (out of 6) are completely empty and everyone is doing 'around' the speed limit. Some are in the right lane doing a few below the limit, some are in the left-most lane doing a few above.
Occasionally, someone who is late to work, emergency services, or whatever goes flying by in one of the left-most lanes.