BOSTON — Boston-area residents who feel there are more cars on the roads and a little less elbow room on the subway may be right.The U.S. Census Bureau in estimates released this week said Boston and four of its immediate suburbs added the most new residents from July 1, 2013 to July 1, 2014.Boston gained nearly 6,000 new residents, with Cambridge (1,962), Everett (1,121), Watertown (997) and Chelsea (980) closing out the top five.Watertown's 3 percent population growth was the largest in the state.