It won’t be a perfect weekend for travelers, but it will finally feel like fall. The Capital Weather Gang says Friday is the most pleasant day for getting out. Along with much cooler temperatures, the forecast for Saturday and Sunday includes clouds and a good chance of rain.

The Nationals’ season is over. The Redskins and D.C. United are out of town, but the Capitals play in Verizon Center at 5 p.m. Sunday. Some travelers will head to the Eastern Shore for the NASCAR races at Dover International Speedway or stay closer to home for the annual Wilson Bridge Half Marathon. In Del Ray, they can stroll through the Art on the Avenue festival Saturday, or enjoy a Taste of Bethesda at the annual food fair.

Here are some highlights of the traffic and transit issues they’re likely to encounter this weekend and beyond. Of particular note are the planned closing Friday night of a left exit on the Capital Beltway in Virginia and a restructuring of the D.C. Circulator bus routes.

Metrorail weekend delays

This weekend’s work zones will affect travel on four lines from 10 p.m. Friday through the midnight closing on Sunday. Metro anticipates this will delay many riders by 20 minutes, but the waits for trains can be longer, especially if you’re waiting to transfer trains.

Red Line: Trains will share one track between Grosvenor and Twinbrook stations during platform repairs. Trains also will share a track between Takoma and Forest Glen while crews install cables and work on some station improvements.

Trains are scheduled to leave the ends of the line every 24 minutes. On Saturday and Sunday between 9 a.m. and 9 p.m., more trains will operate in the interior part of the line, between Grosvenor and Fort Totten. In that sector, trains should arrive at platforms about every 12 minutes.

Blue/Orange lines : Trains will share a track between Eastern Market and Stadium-Armory stations. Workers will be replacing rail fasteners.

Orange Line trains will share a track between Vienna and West Falls Church as workers replace cross ties and insulators. Blue Line trains will share a track between Franconia-Springfield and Van Dorn Street stations during the installation of new rails.

Orange Line trains will leave the ends of the line about every 20 minutes. Blue Line trains will operate between Largo Town Center and Van Dorn Streets. A shuttle train will operate between Van Dorn Street and Franconia-Springfield.

Blue Line trains and the shuttle train will leave their terminals about every 20 minutes.

Green Line: Trains will share a track between Southern Avenue and Naylor Road stations during replacement of rail fasteners.

Metrobus weekend detours

The transit authority will detour some buses around weekend events.

Friday: Routes 9S and 23A will detour from 6:30 to 8:30 p.m. around Crystal Drive in Crystal City between 12th Street South and 33rd Street South for a 5K run.

Saturday: Route B2 will detour from 6 a.m. to 4 p.m. around westbound Good Hope Road SE between Martin Luther King Jr. Avenue and 13th Street where a heavy crane will be working.

Routes 10A and 10B will detour from 7 a.m. to 8 p.m. around Mount Vernon Avenue between East Bellefonte Avenue and East Hume Avenue in Alexandria for a street festival.

Sunday: Routes 32 and 36 will detour from 4 a.m. to 10 p.m. around Pennsylvania Avenue NW between 12th and 14th streets for a festival.

Route 10B will detour from 6 a.m. to noon around South Washington Street between Church and Alfred streets Alexandria for the Wilson Bridge Half Marathon.

Bay Bridge traffic

The Chesapeake Bay Bridge may have extra traffic this weekend because of the NASCAR races in Dover, Del. The Maryland Transportation Authority, which operates the bridge, said it will monitor traffic throughout the weekend and implement two-way operations on the westbound span to ease any eastbound delays. Two-way operations on a bridge with no median are tricky, and the authority does this only in favorable weather conditions.

Half marathon on GW Parkway

The George Washington Parkway will temporarily close from Mount Vernon Circle to Little Hunting Bridge for the Woodrow Wilson Bridge Half Marathon between 6 and 11 a.m. Sunday. The ramps on this southern section of the parkway also will be closed.

There will be two exceptions for southbound local traffic. The southbound right lane will remain open from Little Hunting Bridge to Belle Haven Road, and the southbound right lane will remain open from Vernon View Drive to Stratford Lane to provide local access.

Beltway exit closing

The Virginia Department of Transportation says it plans to permanently close a left exit from the Capital Beltway to Interstate 66 on Friday night. The plan calls for closing Exit 49C, the left exit from the inner loop (northbound I-495) to westbound I-66. Drivers instead will use the ramp on the right side, Exit 49A. The right exit ramp will have two lanes to accommodate the additional traffic.

This change will be tricky for drivers accustomed to using the left exit, and probably will cause some extra traffic congestion until they get used to it.

Exiting motorists will need to be in the right lane as they approach the I-66 interchange. The merge onto Exit 49A has been relocated to before the I-66 overpasses. By the time a driver sees the closed exit go by, it’s going to be too late to move across the Beltway to the open exit.

This closing is required to continue construction of the high-occupancy toll lanes. Traffic will be shifting to the new Beltway outer lanes, and work will begin on a new access ramp to the HOT lanes

14th Street Bridge

The right lane of the northbound 14th Street Bridge is scheduled to close from 7 a.m. to 4 p.m. Saturday. The closed area will start just before the bridge operator’s tower. This is part of the long-term rehabilitation of the bridge. Crews will be working on a bridge pier.

Third Street/Riggs Road NE

The District Department of Transportation has temporarily created a new traffic pattern on Third Street and Riggs Road NE in the Fort Totten area. This is related to the intersection reconstruction at South Dakota Avenue and Riggs Road.

On Third Street between Riggs Road and Second Street, the northbound lane has been reopened. Traffic will be kept on the west side of the street, with one lane in each direction.

On Riggs Road between Chillum Place and First Street, traffic is shifting to the north side of Riggs Road. Two inbound lanes and one inbound lane will be kept open.

The sidewalk on the south side of Riggs Road between South Dakota Avenue and Chillum Place has closed.

On South Dakota Avenue between Riggs Road and Kennedy Street, traffic will remain on the west side of the avenue. One southbound lane and two northbound lanes will be kept open. Drivers will be permitted to make a left onto Riggs Road from both northbound lanes.

Bridges over I-395

The District Department of Transportation this week announced plans to start construction on the Air Rights Tunnel project in Northwest Washington. The Air Rights Tunnel takes Interstate 395 traffic under Massachusetts Avenue NW, north of the Third Street Tunnel.

Construction is scheduled to start in October and continue through spring 2013. The project will rehabilitate the bridges over I-395 on H and K Streets and Massachusetts Avenue.

The bridge surfaces will be upgraded and improvements will be made to the drainage system, traffic signals, street lighting and sidewalks, DDOT said. Some upgrades will also be made in the tunnel below the bridges to improve the lighting and air exchange.

Construction is scheduled for 9 a.m. and 4 p.m. weekdays and may also occur on weekends as needed. At a minimum, DDOT said, one lane will be kept open in each direction on the bridges, and at least two lanes in each direction will be open in the tunnel.

D.C. Circulator changes

The District Department of Transportation is launching a series of changes Monday in the Circulator bus system, eliminating one route, adding another and making further adjustments in the service.

Convention Center-SW Waterfront: The Convention Center-Southwest Waterfront Circulator is being eliminated after the end of Friday night’s service. A new Metrobus, Route 74, started operating this week along the Seventh Street corridor between the Washington Convention Center and the Waterfront neighborhood. The 74 bus costs more to ride and offers less frequent service, but the District said the ridership on the Circulator was too low to continue it.

Anacostia route: DDOT said it will add a route Monday serving neighborhoods east of the Anacostia River for the first time. The route will run from the Potomac Avenue Metrorail Station to Skyland via Barracks Row (Eighth Street SE), but the exact route has not yet been published..

Union Station-Navy Yard: Also effective Monday, DDOT will adjust the route of the Navy Yard-Union Station buses. They no longer will travel west on Constitution Avenue and north on Louisiana Avenue to reach Union Station.

Instead, they will stop on Columbus Circle at the flag poles adjacent to Union Station before turning right on F Street NE and right again on Second Street NE to reach Constitution Avenue.

That means they no longer will stop inside the Union Station garage. Stops on Louisiana Avenue and D Street also will be eliminated.

Bus stop consolidations: On the Georgetown-Union Station and Dupont Circle-Georgetown-Rosslyn routes, some stops that are close together will be combined or eliminated.

Stops at 18th, 19th and 20th streets along K Street NW will be combined into one stop at K Street and 19th Street NW, heading west toward Georgetown. Stops at 18th and 19th Streets on K Street NW will be combined into one stop at K and 19th streets NW, heading eastbound toward Union Station.

Stops will be eliminated at Wisconsin Avenue and P Street NW, both eastbound and westbound; at Wisconsin Avenue and N Street NW heading westbound, and at M and 31st streets NW heading eastbound.

A stop will be added at 35th Street and Wisconsin Avenue, where the Georgetown-Union Station buses turn around to head back toward Union Station.

The consolidations and eliminations of some stops seem like good moves for the overall service, though they will be an inconvenience for some riders.

The Circulator needs to come closer to maintaining the bus-every-10-minutes service that is as much a part of its reputation as the distinctive style of the buses.

Circulator/ART transfers: Riders transferring from Arlington Transit (ART) buses to the Circulator will start receiving a free transfer when paying with their SmarTrip cards. Those transferring from the Circulator to ART will pay 50 cents.

Washout in Charles County

Heavy rains washed out part of Budds Creek Road (Route 234) in Charles County three weeks ago. The Maryland State Highway Administration has announced it will install a temporary bridge over Allens Fresh Run, east of Route 301. The temporary bridge will be about 100 feet long and have two 12-foot wide travel lanes capable of carrying all legal loads. SHA said it expects to open the bridge by the end of November.