Happened to be in Milwaukee a couple of weeks ago at the same time Pres. Obama was there for some fund raising. Kinda cool.
I heard there were 3 routes ready and 1 is selected at the last minute. Both times the procession came down the street we were on.
I say he was driving the Ambulance or a motorcycle....some say they saw him in the Prius taking some back streets. In any case, still cool.