Many years ago I had the honor of seeing a the Presidential motorcade of Ronald Reagan returning from a speech at the UN. The motorcade hauls A**. So as much as Cindy Sheehan makes it look like a big insult to her that the motorcade sped by, It's just the way it's done!
I've been told all that speeding stuff is entirely the call of the SS. THEY are tasked with protecting the POTUS from wack-jobs like the little general and her hand maidens.
I'll never forget my very first protest in 1997.... We (hubby and me) were across the street from a swanky hotel/fundraiser for Algore. Only three of us with our goofy signs. A SS agent came out, walked to the very tip of the curb, facing us, with his back to the rich folks rolling in.... When he positioned himself so that no one but us could see his face, he broke out in a HUGE GRIN!!
....One of my favorite memories!
I saw the film of the motorcade. They were not going fast enough to kick up dust. She was lying yet again. (I bet in urban areas with all of the sniper site possibilities they book.)