The following is a list of holiday closings and schedule changes for the metropolitan area today:

FEDERAL GOVERNMENT Federal offices Closed. Mail Post offices closed; express mail and special delivery only.

TRANSPORTATION Metrorail

Trains will run from 8 to 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. 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 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. Call 251-7433 between 8 a.m. and 4 p.m. 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 closed. 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. Libraries Closed. Traffic, parking Nonrush-hour traffic regulations. No meter fees. All Division of Motor Vehicle offices closed. Trash No regular collections. Supercan collections that normally would have been made yesterday will be made today. Liquor stores Owners' discretion.

MARYLAND Banks Most banks closed. Courts Closed. State offices Closed. County offices Closed. Libraries Closed. Parking Saturday parking regulations in Montgomery and Prince George's counties. Municipalities may vary. Trash 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 in Montgomery County; owners' discretion elsewhere.

VIRGINIA Banks Most banks closed. Courts Closed. State offices Closed. County and city offices Closed. Libraries Closed. Traffic, parking

No HOV restrictions on I-66, I-95 and I-395. The reversible lanes down the center of I-395 will remain open for southbound traffic only until 8 a.m. Sunday. 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. Landfills open in Fauquier, Prince William and Stafford counties; closed in Loudoun County. Liquor stores

Closed.