^ I've seen the feature where Niko or any peds try to get in a car and they get stock in the door and get dragged with the car, but it's only for a few seconds before they can't hold any longer.
I aslo hoped that you could take stuff from the trunk, carry weapon on your back. In the first or second trailer we saw Niko carrying bags in this back, we all thought that there were some kinds of weapon in them, but after playing the game we know that it's not like that. It's the money bag from the bank robbery. This was a very huge disapointning for me and most likely for other aswell.