Wikipedia
SmarTrip is a contact-less stored-value smart card payment system managed by the Washington Metropolitan Area Transit Authority (WMATA). The Maryland Transit Administration (MTA) uses a compatible payment system called CharmCard. A reciprocity agreement between the MTA and WMATA allows either card to be used for travel on any of the participating transit systems in the Baltimore-Washington metropolitan area. Unlike traditional paper farecards or bus passes, SmarTrip/CharmCard is designed to be permanent and reloadable. For the rest of this article, "SmarTrip" will refer to both unless there is a specific difference between the two.
WMATA began using SmarTrip for payment on Metrorail in 1999 followed shortly by Metrobus and Metro parking lots. It was later extended to other public transit systems throughout the region. SmarTrip users receive discounts on Metrorail fares. Although WMATA initially drew criticism due to the limited number of SmarTrip sales locations, distribution has expanded to local convenience stores and supermarkets. By late 2012 all Metrorail stations were equipped with SmarTrip vending machines.
In October 2010, WMATA announced that it was working on a replacement system because the company that makes SmarTrip cards has since gone out of business. However, the transit agency found an alternate manufacturer to produce additional cards until a new payment system is introduced. After March 6, 2016, SmarTrip cards are the only Metrorail payment method, and paper farecards will no longer be accepted.