Running on concrete sucks, I can completely understand why these people are on the bike lanes. If they're doing things right they should see bikers coming toward them and have the common sense to get the f out of the way. Back when I did a lot of running that's what I did, same when I'm on a trail and you come up to a bunch of MTB'ers. This should be obvious from a safety perspective, but I guess that gets blown into the wind for most people until the moment they get hurt.
Again, as has been asked are there any scientific studies to back up this claim?