If you have three lanes, the right lane should be for people who want to drive UNDER the speed limit, or for people who are about to exit, or for those entering. The middle lane should be for those who want to go about what the speed limit is. The left lane, in the mind of the drivers, should be the passing lane, which drivers should get out of if someone is wanting to go faster than you. In a two-lane situation, it should be merely slower and faster drivers, slower traffic moving to the right, left lane the passing lane, regardless of whether the drivers should go faster or slower, If you only have one lane, as in a two-lane highway, just go the speed limit. It is courteous to pull over to let speeders pass, but less obligatory than the above. It has occurred to me that a lot of traffic jams and logjams and unruly traffic would be quelled if people did the above. You have a right to drive whatever speed you think you can get away with, but no tailgating and no blocking others, holding up traffic.