Metro riders will no longer be allowed to carry a negative balance on their SmarTrip cards.
The new rule will go into effect Jan. 8, 2018, Metro said.
Metrobus riders who have a negative balance will not be allowed to board the bus, while customers on Metrorail will be directed to an Exitfare machine.
The transit system noted that Exitfare machines only accept cash or coins.
Metro said unresolved negative balances have added up to about $25 million over the past 17 years.