You may ram to kill Most wanted criminals (6 stars) - threat orange criminals (2-5 stars, need to check their /crimes to be sure they are a threat or not. Hit and run, Assault, Shooting in public, Weapon threat, Robbery (Unknown), Robbery (shop name), Attempt murder crimes make a player a threat and cops can kill them)
So ramming to kill them is allowed.But carparking is not allowed.