According to the Potomac and Rappahannock Transport Commission, the SmarTrip card is a rechargeable card that will allow you to pay for travel on public transportation in Northern Virginia, Maryland and the District of Columbia. It is usable on both the Metrorail and Metrobus. Check the balance on your SmarTrip or add money to the balance at any Passes or Farecard machine in the public transportation system.
Go to any Passes/Farecard machine. These can be found on buses or at a Metrorail station.
Push the “Check Value” button on the Passes/Farecard machine.
Touch the your SmarTrip pass to the target on the Farecard machine. Your current SmarTrip balance will be displayed on the screen.