Occasionally, drivers have accompanied passengers beyond the vehicle. Shearer was a driver four years ago, and he remembers escorting an officer up the escalator to the Texas and Wyoming ball at the Washington Convention Center.
"It's cram-packed, everyone's shoulder to shoulder with movie stars and governors and congressmen," he said. "I get bumped, and there's this hand on my shoulder and she said, 'Oh, I'm sorry!' and I did a double take. It was Bo Derek," Shearer said. Even the officer was impressed. Shearer called his mother.
Coast Guard Petty Officer 3rd Class Timothy Jeffries instructs the volunteers including Joseph Johnson, right, on staying aware of explosive devices in cars.
(Robert A. Reeder -- The Washington Post)
Army Staff Sgt. Debra Flucker, 31, of Greenville, Ala., a member of last week's class, was excited about the prospect of meeting dignitaries but said the main draw of the inauguration was working with other service members and senior officers.
"It's hard when you're on the other side of the house. I'm enlisted, and you don't normally get to meet the people making decisions for us," said Flucker, a research assistant at Walter Reed Army Institute of Research in Silver Spring. "It's a great opportunity."
Some of the students concede that they are nervous. "I'm mostly worried about getting lost," said Army Sgt. Andre Brown, 21.
Brown drives five-ton supply trucks at Fort Detrick and was lured to work the inauguration in part by the prospect of a high-speed defensive driving class, which never materialized.
That course was reserved for the instructors. Chaddock, for example, spent three days crashing cars on a racetrack in Richmond, and driving through the District trying to find actors playing terrorists.
Last week, he offered his charges real examples culled from years of experience, including those he spent transporting classified documents for the Department of Defense and driving for the office of the secretary of defense.
"My biggest thing is I tell them don't be afraid to ask a question. There's no such thing as a dumb question," said Chaddock, who has been with the Air Force for 18 years.
Cut through Rock Creek Park instead of taking 16th Street NW to Walter Reed, Chaddock said. Avoid the steel grates on the bridge to Anacostia, because they tend to freeze. Avoid K Street because it's difficult to get off of. "Dupont Circle," he said, shaking his head. "Know where you're going. You need to be in certain lanes."
In a large white bus, Chaddock shepherded his class past the Pentagon, through Fort Myer, past neat homes -- including one belonging to the chairman of the Joint Chiefs of Staff -- and over the Roosevelt Bridge.
As the landmarks passed, Air National Guard Tech. Sgt. Kelly Daun, 28, said she expected to be awake and dressed as early as 2 or 3 a.m. on Inauguration Day.
"It doesn't really matter who or what I drive. I just think the whole experience is exciting," said Daun, who manages supply equipment and teaches sixth- and seventh-grade math in Las Vegas. "It only happens every four years. I don't really know what to expect."