Yeah on I-83 it's common for drivers going south from Harrisburg to stay in the left lane when leaving the beltway on I-83 because of the multiple on ramps with stop signs on them all because of there short distance and amount of people who pull out constantly without giving themselves enough time to get up to speed forcing you to slam on the brakes so you don't rear end them going below the speed limit around the curve especially with the construction still going on. It just makes sense to stay in the left lane for about a mile after getting off the beltway before getting into the right lane right before the first hill where you start to lose gears if you are heavy. Parts of I-80 have problems with the really short ramps as well. Merging onto I-81 from I-80 is a good example.
I just follow my instincts, and often times there ends up being an emergency vehicle on the roadside ahead, so I'm better off moving over before the line of traffic boxes me in (it can serve more than one purpose, ya see).