The following is a list of holiday closings and schedule changes for the metropolitan area Friday and Saturday.

FEDERAL GOVERNMENT Federal offices Closed. Mail Friday: main post office open; some branches closed. Saturday: post offices closed; express mail and special delivery only.

TRANSPORTATION Metrorail Friday: trains will run 8 a.m. to midnight on a Saturday schedule with trips every eight to 12 minutes; nonrush hour fares. Free parking at all transit authority-operated lots. Saturday: trains will run from 8 a.m. until 3 a.m. Sunday. From 8 a.m. until 10 a.m., they will run every 8 to 12 minutes; from 10 a.m. to 3 p.m., every 6 to 8 minutes; after 3 p.m., every 4 to 6 minutes. All six-car trains will be operating on all lines. Fares, 75 cents per trip, collected in barrels. Senior citizens and handicapped riders with valid WMATA identification cards will pay 25 cents per trip. Valid flash passes will be accepted, along with transfers from Metro buses, Alexandria DASH and Montgomery County Ride-On buses. Metrobus Friday: Saturday schedule, with additional service on some lines; nonrush hour fares. Saturday: Saturday schedule, with extra service to Addison Road, Ballston, Brookland, Dunn Loring, Friendship Heights, Huntington, National Airport, Pentagon, Potomac Avenue, Rhode Island Avenue, Silver Spring and West Falls Church rail stations until 3 a.m. Sunday. After the fireworks, additional buses, marked "July 4 Special," will operate from the mall area to Friendship Heights, Silver Spring, Anacostia, Rosslyn/Ballston, Glen Echo, Eastover/Marlow Heights, Takoma Park/Petworth and Pentagon Station. Free transfers between bus and bus and bus and rail. Fares are 75 cents per trip, with exact change required. Senior citizens and handicapped riders with valid WMATA identification cards will pay 25 cents per trip. Valid flash passes will be accepted. Montgomery County Ride-On Sunday schedule, with extended hours July 4. Call 251-7433 between 8 a.m. and 4 p.m. July 4 for route information. Maryland Rail Commuter Will not operate. Alexandria Transit DASH Sunday schedule. Fairfax Connector Buses Sunday schedule.

DISTRICT OF COLUMBIA Banks Most banks open Friday, closed Saturday. Courts U.S. District Court and D.C. Court of Appeals closed. D.C. Superior Court closed except for lockups and arraignments. D.C. government Closed. Schools Closed. Libraries Closed. Traffic, parking Non-rush hour traffic regulations. No meter fees. On Saturday, all Division of Motor Vehicle offices closed. Trash No regular collections Friday or Saturday. Supercan collections normally scheduled for Friday will be made Saturday. Liquor stores Owners' discretion.

MARYLAND Banks Most banks open Friday, closed Saturday. Courts Closed. State offices Closed. County offices Closed. Schools Closed. Libraries Friday: closed in Anne Arundel, Calvert, Charles, Montgomery and St. Mary's counties; open in Frederick, Howard and Prince George's counties. Saturday: closed. Parking Friday: Sunday parking regulations in Montgomery and Prince George's counties. Saturday: Saturday parking regulations in Montgomery and Prince George's counties. Municipalities may vary. Trash Friday: regular trash pickup in Anne Arundel, Howard, Montgomery and Prince George's counties. Landfill closed in Frederick County; open in all other counties. Saturday: no trash pickups. Landfills open in Calvert, Frederick and St. Mary's counties; closed in Anne Arundel, Charles, Howard, Montgomery and Prince George's counties. Liquor stores Open Friday and closed Saturday in Montgomery County; owners' discretion elsewhere.

VIRGINIA Banks Most banks open Friday, closed Saturday. Courts Closed. State offices Closed. County and city offices Closed. Schools Closed. Libraries Friday: closed in Arlington, Fairfax, Fauquier and Prince William counties and the City of Alexandria; open in Loudoun and Stafford counties. Saturday: closed. Traffic, parking

No HOV restrictions Friday or Saturday on I-66, I-95 and I-395. The reversible lanes down the center of I-395 will remain open for southbound traffic only through Sunday morning at 8 a.m. At that time, the lanes will reverse to accommodate northbound traffic. Trash Regular collection schedule in Arlington, Fairfax and Alexandria. Collection schedules vary according to company in Fauquier, Loudoun, Prince William and Stafford counties. Friday, landfills closed in Fauquier and Stafford counties and open in Loudoun and Prince William counties. Saturday, landfills closed in Loudoun and open in Fauquier, Stafford and Prince William counties. Liquor stores Friday: open. Saturday: closed.