I take a bridge to work every day. I would have to say the majority of vehicles are not centered in their lane, as if they are "scared" of the median. I know that when I was 16 and learning to drive, my dad told me to get closer to the median, my vehicle is not so wide that I have to be off center. If we remove these folks off the road it would be significant, so rather maybe they should be retrained.
Then, again there are so many oddities in PA. There are people who come to a complete stop, behind the stop line, on a solid green. They let the light turn yellow, then red. They wait for the next cycle which will give them a green arrow. These folks should have their licenses suspended, then revoked.