We live about a mile from the Vice President's House at the Naval Observatory, so it's actually a somewhat common sight to see the VP's motorcade go by. How do we know it is the VP and not the President? A couple of clues: 1) The VP's white flag on the Suburbans. The President's flag is Blue. 2) The road isn't 100% closed. The cars move in a 'rolling roadblock' clearing cars as they go. The President is a full closure. 3) No ambulance at the back. 4) No WW3 vehicle. The President's motorcade has a few vehicles used for fighting WW3 (communication type vehicles). While there is a comms vehicle here, they don't have the bigger 'football' vehicle that you see with the President's motorcade.