WASHINGTON -- It's that time of year again: The Rock 'n' Roll Marathon is coming to town.
The cross-city trek, the first of many annual road races in Washington, usually takes drivers by surprise.
The 2014 Rock 'n' Roll USA Marathon and the CareFirst Rock 'n' Roll USA Half Marathon begins at 7:30 a.m. on Saturday, March 15. Many streets throughout the D.C. will close for the race course from early morning through early afternoon.
This year's course starts on Constitution Avenue and routes runners along the National Mall, back-and-forth across the Memorial Bridge, on Rock Creek Parkway into Woodley Park, and along streets through Adams Morgan, Columbia Heights, Capital Hill, the Navy Yard, Anacostia and River Terrace. The Half-Marathon and Marathon end at Lot 7 at RFK Stadium.
The first portion of the race will affect drivers in Northwest Washington. As the last runners pass across the Memorial Bridge and Rock Creek Parkway, police will likely reopen the roads.
The routes near the end of the marathon course between the Frederick Douglass Bridge and RFK Stadium will remain closed the longest.
The map above illustrates the 2014 race course and offers estimated duration of closures and a few alternate routes.
On Saturday, Metrorail opens its doors two hours early, at 5 a.m., to accommodate runners and spectators. Participants traveling by train should use the Federal Triangle, Smithsonian or Archives stations to access the start line.
Metro says the Orange, Blue, Yellow and Green lines will operate on their regular weekend schedules, except for the Greenbelt Station on the Green Line and Franconia-Springfield station on the Blue Line
Trains on the Red Line will run every 16 minutes between Shady Grove and Glenmont. Metro says additional trains will provide service from 9 a.m. to 9 p.m. between Farragut North and Silver Spring.
Several Metrobus routes are affected by the race closures. Buses won't proceed beyond most race closures until they're lifted.
In addition to the Rock 'n' Roll Marathon, the Four Courts Four Miler Race will block roads in northern Arlington, Va. Arlington County Police report Va. 110 North and portions of Wilson Boulevard will be blocked from mid-morning until 11 a.m.
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