FYI. I am not a UPS employee, I just know a ton about them
The "Hub" has direct connection with the drivers, and can see where they are at ALL times ( live - well in the updated Hubs ). Certain workers can send messages to the drivers, and its just like a text message on your cell phone. Only problem is, if the drivers dont want to answer you cant force them too.
Believe me I have stories about both FedEx AND UPS that would make your heads spin. Do a little google searching and you will find some of them. It's amazing