Travel tip: always carry more than enough bills and change specially quarters for toll fees. This will save you all the hassles of paying extra fees and possible penalties. Keep your receipts too, just in case.
Stay to the left lane to exit the Dulles Toll Road and use the toll-free Dulles airport access road. The airport access road runs inside the toll roads all the way to the airport.
They are toll free.. however if you are using GPS it may take you to the toll roads. I believe my car was $3. I didn't have cash so I had to call the next day and pay for the toll and administrative fee of $6. Just have $10 cash with you just in case.
The Dulles airport access road is toll free I think.
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