Metro will change or curtail 180 bus routes starting today so that they can feed area commuters into the new subway system.

Buses will be rerouted to provide easy access to the subway for patrons at the Pentagon, National Airport and Union Station Metro stops.

Many Shirley Highway buses that used to run to Farragut Square will be stopped at the Pentagon, where commuters can continue by train. Bus service will continue from Virginia across Memorial Bridge and along Constitution Avenue, and across the 14th Street Bridge into the Southwest and Federal Triangle areas.

Commuters using the George Washington Parkway corridor will be encouraged to board the Metro at National Airport, but some buses will continue into the District of Columbia.

District residents coming from Northest Washington to downtown on the Benning Road and H Street NE lines will find that many of their buses terminate at a new terminal on top of Union Station. Some buses will continue into downtown Washington, however.

There is no transfer from bus to subway. Commuters will have to pay separate fares. However, commuters can transfer from the subway to the bus. They must get their transfers from automatic dispensers in the subway station where they board the train.