Food trucks line the street on 7th Street SW at L'Enfant Plaza on Friday in Washington. (Ricky Carioti/The Washington Post)

Jacob and Carl Triplett launched their food truck in the spring in part to compensate for the income they lost when Jacob was let go from his banking job last year. On Tuesday, the Tripletts learned that their budding business would have to support them both: Carl was furloughed as an IT management analyst for the U.S. Department of Transportation.

The problem, he said, is that the partners aren’t sure they can squeeze more money out of Carolina Q, their barbecue shack on wheels, which sells chopped pork shipped straight from a North Carolina smokehouse. After all, the government shutdown that temporarily put Carl out of work is the same one that is crippling the food truck industry in the District. Sales at several gourmet trucks are down 50 percent or more; another has had to lay off employees; and others have decided not to operate, or operate less frequently, until the shutdown is over.

In fact, if one thing has become clear to District food truck owners since the government shutdown began Tuesday, it’s that they rely heavily on federal workers to keep their businesses afloat. Some of the trucks’ most popular locations — L’Enfant Plaza, the Navy Yard, Federal Triangle and streets surrounding the State Department — are near federal buildings full of workers who go out to lunch.

Carl, 48, put his situation into sharp relief: He and Jacob, 34, were married in March, and about a month later they launched Carolina Q, a business into which they sank all of their savings. The truck had just started to break even and prove that it could become a moneymaker for the couple. But until this month, neither Jacob nor Carl had taken cash out of the business, and they’ve only taken small amounts. What’s more, Carl isn’t even certain he will receive back pay once the shutdown ends.

“Now, we really need to take money out of the business,” said Carl, a resident of Mount Vernon Square. “We put all of our savings into this business. It’s kind of a perilous time now.”

On Thursday afternoon, Layth Mansour was pacing near his trucks,Philadelphia Steak Bites and George’s Buffalo Wings, which were parked on C Street SW, just outside the L’Enfant Plaza Metro station. The nearby Transportation Department and Federal Aviation Administration buildings were apparently hit hard by the shutdown; Mansour said sales at both trucks were down 65 percent. His business, he added, employs 12 people.

“I’m not going to be able to afford the employees,” Mansour said as he stood on the nearly empty sidewalk. “I’m losing money if I come out now.” Mansour figured that if the shutdown was not resolved by Monday, he’d pull his trucks off the street, essentially putting a dozen more people out of work.

The proprietors of the Stix truck have already cut loose their prep and grill cooks “because we’re unable to pay them,” co-owner Leah Perez said. “It’s just pretty sad out there.”

Josh Saltzman, co-owner of the PORC truck, has decided to take his vehicle off the streets. It took just one day of vending for Saltzman to make the call. On Tuesday, his barbecue truck stopped at Franklin Square, a normally reliable sales location not dependent on federal workers. His sales were off by 50 percent. “Our business is pretty steady all the time,” Saltzman said. “When I don’t see those kind of [regular customers], I’ve got to assume it’s because of the effects of the shutdown.”

But Saltzman is fortunate, he noted. He has another business to fall back on. He’s a partner with Kangaroo Boxing Club, a separate bricks-and-mortar restaurant with a menu heavy on barbecue. The three PORC employees, one full time and two part time, will still get paid during the shutdown, Saltzman said. “We don’t think it’s fair that they get penalized” by the government’s actions, he said.

The shutdown comes at a difficult time for truck owners, said Che Ruddell-Tabisola, political director for the recently renamed District Maryland Virginia Food Truck Association. Mobile vendors have already felt the effects of sequestration, the automatic, across-the-board federal budget cuts that required countless furloughs, leaving fewer dollars to spend on street food. But now truck operators have weeks before the weather turns cold and keeps customers indoors.

“It’s scary to think that this is going to happen for a couple more weeks. . . . Then the temperature drops, and we have to compete with the elements,” said Ruddell-Tabisola, who also co-owns the BBQ Bus, which experienced a 40 percent drop in sales during a stop earlier this week. Ruddell-Tabisola added that four families depend on BBQ Bus to make payroll.

“It makes me so angry that our elected leaders can’t fulfill their responsibility,” Ruddell-Tabisola said.

Sandra Panetta, owner of the Sweetbites dessert truck, has experienced government shutdowns from two perspectives now. Back in 1995-96, when the federal government experienced its last shutdown, Panetta was a policy analyst for the Environmental Protection Agency. It was a scary time, she recalled: She had just bought a house and didn’t know if she was going to get her back pay at the end of the shutdown.

This time, she’s experiencing the shutdown as a business owner and single mother with two teenagers to feed. “It’s equally terrifying,” said the McLean resident. To try to keep her sales up, Panetta said she’s steering her truck away from locations tied to federal workers and instead focusing on spaces such as Farragut and Franklin squares. She still figured that her sales are between 25 percent and 50 percent lower than normal. Parking enforcement officers aren’t helping, Panetta said. On Friday, they cited everyone on Farragut for parking during rush hour.

A parking ticket is “a lot of money to take out of your bottom line when times are tough,” Panetta said. “They could have cut us a break.”

In one way, Panetta is more fortunate than the Carolina Q operators. She has a government pension to help pay bills when sales are slow. But if history is any gauge, Panetta can offer one hopeful piece of information to the Tripletts: When the shutdown ended in 1996, she got all her back pay. And Congress has already begun moving to do the same again.