You can also take the Washington Flyer bus for 5 dollars per person to the Whiele-Reston East Metro Station where you can take the Silver line directly to metro center in downtown DC where they can transfer to a red line train toward Glenmont, which goes to union station. The whole trip will take about an hour to hour and 15 minutes.
Take metro from main terminal to Wiehle and transfer to silver line to metro center, onto red line glemmont. Get off at Union station.
The metro is not built to the airport, yet... Take a taxi to Union Station or taxi to Reston East Station
I just rode the metro yesterday. All day pass is $13. You can ride it as often as you want for 24 hours. Lines are color coded and maps are on the metro cars. Ex. You may be on a blue line but your destination is on a yellow, so where the 2 colors intersect, is where you would tranfer from blue line to yellow. They have helpful agents at entry points. I would ask if the pass includes all metro busses and trains. I think so, but not certain.
You can call DullesLimousine.biz they have sedans to DC with advance notice
Traveler can take the 5A bus to L'Enfant Plaza Station from there it can the green and yellow lines north to Gallery Pl-Chinatown and take the red line train east to Union Station.
Take the Washington Flyer to Wiehle Metro station. Take a 7000 series train to Metro Centa. Then switch to Red Line and scoot to Union.
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