PA is notorious for deer/vehicle accidents. I heard on the local radio that its one of the worst states for it (though it WAS the radio and I didn't do any background research so who knows). I used to travel back and forth from PA to WV a lot and to keep myself occupied, I'd always count the deer carcasses on the road.

20 a day seems like a lot but come to think of it, I see a lot of dead deer on the road. Some I've hauled off to the side by myself since they were left for dead in the middle of the road and was a traffic hazard.