I've been in multiple presidential and foreign heads of state motorcades. From that perspective it's fun being able to go from one end of the city to another without having to make a single stop.
A point and shoot with an iPhone, taken in the Tehachapi Mtns. California, on my way home. I was listning to Aaron Copland's "Fanfare for the Common Man" at the time. That was a very powerful and moving combination.
There are many theories based on location, orientation, shape, etc. They are mainly educated guesses. Attached is a great video (not me, not taken by me) of that particular panel that might answer your question...or pose many new ones.