The Washington Metropolitan Area Transit Authority offers a reduced fare program on the Metrobus and Metrorail for individuals with disabilities.
Metrobus and Metrorail customers with disabilities may be eligible to ride at a discounted rate.
http://www.wmata.com/accessibility/reduced_fare.cfm
Metro Disability ID & SmarTrip Card Application Form
http://www.wmata.com/accessibility/doc/Reduced_Fare_Application.pdf