It says you cannot call your car when you are dead or in an interior. It's there for a reason. Cars spawn farther away from you and when you are in an interior you are at a completely different place. For ex. If you enter SFPD you are actually located in LS at that exact time (i think so) and not in SF. You can check by opening the map. So, the cars would spawn in LS and not near SFPD.