With fewer people commuting to work, Metro is hemorrhaging about $400,000 each regular weekday of the government shutdown, according to Metro General Manager Paul Wiedefeld.

As Virginia Senator Mark Warner put it: “holy smokes.”

A preliminary analysis showed that train ridership has decreased by 16 percent and bus numbers are down 8 percent, Wiedefeld told senators from Virginia and Maryland in a letter Thursday.

He also warned that it’s possible that the system will see a further drop in passengers after January 21, when federal workers at many agencies stop receiving subsidized rides through SmartBenefits.

“They can’t afford any loss in ridership, because that’s been a trend they’ve been experiencing and it’s hurt them financially and this would just deepen that problem,” economist Stephen Fuller told WAMU earlier this month.

About 145,000 federal workers in the region are affected by the shutdown (40 percent of the region’s total federal workforce), along with an unknown number of the area’s 400,000 federally contracted employees.

The effects of the impasse can also be seen on the region’s roads. An analysis released this week by the National Capital Region Transportation Planning Board found a “considerable reduction in congestion” during the morning rush hour. Travel times have improved by more than 40 percent on some stretches of highway.

If the shutdown—already the longest in U.S. history and nearing the one month mark—goes on much longer, WMATA might consider reducing service during rush hour or using fewer eight-car trains. And down the line, it might need to ask Virginia, Maryland, and the District for an additional infusion of funds.

Metro says it is also “left with unreimbursed expenses” from the federal government totalling $33 million. By the end of January, that figure would grow to about $50 million.

On the bright side, Wiedefeld says he doesn’t believe the shutdown will affect the agency’s credit rating.

The shutdown’s effects go beyond the purely financial. Wiedefeld also told senators that it has already caused delays for a number of infrastructure projects, and might eventually affect a long-awaited transition in safety oversight back to a local body.

“At a time when Metro already is undertaking substantial, disruptive projects to improve safety and reliability, President Trump’s shutdown is jeopardizing the health and stability of the entire Metro system,” said Warner, along with Virginia Senator Tim Kaine and Maryland senators Ben Cardin and Chris Van Hollen in a joint statement. “This wasteful, destructive shutdown must come to an end.”