The federal government owns and operates about 645,000 vehicles.  Among them are about 200,000 passenger vehicles, 78,000 heavy-duty trucks, 47,000 vans, 847 ambulances, and three limousines.   About 225,000 vehicles are operated by the Postal Service.   Each year, these vehicles are driven about 4.5 billion miles and use about 400 million gallons of gasoline, producing 3.5 […]