More than seven million of Washington, D.C.'s, 22 million visitors last spring arrived in the city as part of a group that relied on chartered buses or motorcoaches, said the Washington D.C. Convention and Visitors Association. That number represents those who rode into town from another city or boarded the vehicles at local airports, hotels or convention facilities. Buses also act as an intermodal link, carrying commuters to and from a Metrorail or bus. The American Bus Association estimates that, year round, tour and charter buses in D.C. keep more than 1.8 million cars off of local roads. The 200 buses that visit the city daily year round, if fully loaded, bring more than $7,000 per overnight stay to its destination, the ABA says.