President George W. Bush's motorcade had a minor accident Sunday when the ambulance that routinely trails the president in case of an emergency crashed into a support vehicle on the way back from the Camp David presidential retreat. Secret Service spokesman Jonathan Cherry said no one was injured and the motorcade did not stop before arriving at the White House. The presidential limousine, which travels near the front of the motorcade of more than a dozen vehicles, was not involved. The accident occurred a few blocks from the White House. The motorcade's lead vehicles slowed down, but the ambulance did not stop in time and rear-ended a Chevy Suburban carrying high-tech communications equipment, damaging the back bumper and doors. The Suburban in turn hit a support van in front of it. Cherry said all three vehicles had minor damage.