It’s 4:30 on a cold November morning in Astoria, Queens, and David Belanich ’05 swings his car’s headlights across a padlocked urban parking lot. He hops out and opens the lock, shivering, and drives inside. There in front of him is a long row of empty Mister Softee ice cream trucks, parked for the night. These trucks are spooky, in the manner of deserted amusement parks. This is a not-bad place for a Sopranos-style mob hit.

Belanich directs his headlights into a far corner, toward his own food truck, a former FedEx delivery vehicle he’s had spotlessly and cheerfully refurbished. From it he dispenses, on Manhattan’s streets, a more sophisticated product than Mister Softee ever dreamed of: his own blend of tart, high-end frozen yogurt, as well as coffee from the celebrated indie brand, Stumptown Coffee Roasters. In a few hours he’ll flip on his truck’s neon sign, which casts a warm and welcoming yellow glow. In loopy cursive script it reads, appropriately enough: Joyride.

But first, there’s work to be done. Belanich fires up his truck’s generator and checks his supplies, including steel containers of fresh toppings: mangoes, kiwis, pomegranates. After making sure everything is stowed tightly—things tend to bounce around during the pothole-filled drive into Manhattan—he hits the road. At 7 a.m., he glides into a favorite spot on Park Avenue between 26th and 27th streets, in front of the landmark 1928 New York Life Building. He brews some coffee, does some prep work, and bingo: Joyride is open for business.

Customers arrive almost immediately. Even though Joyride is parked here only on Tuesdays—it occupies a different location around the city each day—there are regulars who brandish “Buy 10, get one free” cards. Joyride has only been operating since July, but already it’s made a name for itself in Manhattan’s flowering and increasingly hip food truck scene. The trend-spotting Web site Daily Candy praised Joyride’s “buzzed” frozen yogurt—fro-yo that’s been spiked with caffeine—and also a honeylike topping called jaggery, often derived from the sap of Sri Lankan palm trees. This isn’t your grandmother’s frozen treat.

Joyride has won admirers, too, for its inventive and witty coffee specials, including the Jeffrey Paul, a kind of ultimate cafe mocha made from double shots of espresso and delicate MarieBelle hot chocolate, dusted with espresso grinds and chocolate shavings. Then there’s the Balzac, essentially the same drink with the addition of gently heated organic milk. The truck also sells pastries and, in the fall, fresh cider doughnuts.

The good press has been a bonus, but Belanich isn’t taking any chances in terms of getting the word out. “Excuse me,” he says, allowing a female employee to take over the customers for a minute. “I almost forgot to do the social media.” He pops out his iPhone and posts Joyride’s location on Twitter and Facebook. Then he updates his location on a real-time online food truck map operated by Zagat, the restaurant guide company. “There,” he says, smiling. “Now the world can find us.”

Operating a frozen yogurt truck in downtown Manhattan is not where David Belanich thought he’d find himself when he left Middlebury six years ago. Belanich, who grew up in Great Neck, Long Island—his Croatian-born father worked in real estate—was a political science major who, after graduation, spent two years pursuing a Ph.D. in political science at Yale. When he took a year off from Yale to spend time with his father, who was ill, he never went back. “I didn’t want to write any more papers for a while,” he says. “I wanted to do something on my own, something more exciting, and to see what happened.”

He teamed up with a friend, Lev Brie, a Columbia graduate, and his younger brother, Adam Belanich, a Dartmouth grad, and began kicking around business ideas. There were plenty of them. They debated starting a finance company or a media aggregator Web site. (“None of us are programmers or journalists, so the media site was kind of a non-starter,” he admits.) They opened a small tutoring company—it is still running—before hitting on the idea of a frozen yogurt truck. “A lot of people my age don’t want ice cream any longer,” he says. “They want something better and more healthy.”

Once upon a time in America the idea of dropping out of Yale to run a food truck would have seemed absurd. To many people, it surely still does. But food is taken more seriously every day; it’s its own kind of cultural pursuit, and it is attracting the types of creative and ambitious young people who would have scoffed at the field two decades ago.

The world of street food is also rapidly changing. On Manhattan’s streets, you used to be able to pick up a cup of coffee from a Greek or Afghan vendor or a hot dog from a cart run by Dominicans. There were a lot of pretzel, smoothie, nut, and kabob carts, too. These days, though, you can find sophisticated sandwiches, wood-fired pizza, and almost anything else. And behind the counter, you’re as likely to find an MBA as a struggling recent immigrant.

The first thing Belanich and his partners did, after deciding to start Joyride, was buy a used FedEx truck on eBay. “We spent about $9,000 on it,” he says. They picked it up in Vermont and brought it back to New York to be outfitted. A lot of thought went into the truck’s brushed-steel interior, and to its coloring and logo. Then the three got lucky, winning a coveted New York City mobile food vendor permit in an official lottery. (There are 3,000 such permits in New York. Only a few new ones are issued every year.)

“The great thing about a food truck is that you’re not paying rent,” Belanich says. “But there are a lot of hassles. It’s not like a restaurant where you can just turn the water on. You’ve got to fill your tank in advance.” If he needs to use a bathroom, he jogs up Park Avenue to a nearby McDonald’s.

The hassles don’t end there. “Nobody likes food trucks except your customers,” he says. “Restaurants don’t like them. Neither do small coffee vendors and other food trucks.”

It took Joyride a while to learn where they could park the truck on New York’s streets. “In the first month, we got three tickets,” Belanich says. Sometimes restaurant owners complain when he pulls up, and sometimes neighbors don’t like his truck’s noisy generator. “We’ve taken serious measures to reduce the noise,” he says.

As Joyride becomes better known in Manhattan, different sorts of offers are pouring in. Belanich was asked to bring the truck to the movie set of Premium Rush, and the truck has also served coffee and yogurt on the set of the TV show Gossip Girl. He’s often asked to take the truck to weddings, bar mitzvahs, and private parties.

The long-term plan? Belanich says it’s to purchase more trucks, and perhaps to turn Joyride into a national franchise. “It’s a lot of work,” he says, “and a lot of brutal early mornings. But I am having more fun now than anytime in my life.”

He serves a cup of steaming coffee to a gregarious businesswoman in a bright scarf.

“People always smile when they see our truck, because it’s happy looking,” he says. “To be honest, it always makes me smile when I see it, too.”