Apparently, all it takes to be a volunteer driver in the presidential motorcade is a driver’s license, a clean record, and a friend in the White House, according to the New York Times.
Michael Schmidt writes (emphasis added):
At the front of the [Presidential Motorcade] were bulletproof black sport utility vehicles and limousines driven by Secret Service agents who had spent hundreds of hours learning how to maneuver at high speeds.
Bringing up the rear were police cars with their lights flashing and a Secret Service ambulance that follows the president wherever he travels.
And in between were several vans filled with White House staff members and journalists, being piloted by volunteers like Natalie Tyson, a 24-year-old Bay Area graduate student wearing fluorescent orange sunglasses.
“Wow,” she exclaimed as she hit the gas and the van lurched within a few feet of the one in front of it. Then she slammed on the brake. Then she hit the gas again.
“Sorry about that,” she said.
She returned her hands to the textbook 2-and-10 positions on the steering wheel.