America's 20th largest bus service -- hauling 120,000 riders a day -- is profitable and also illegal. It's not really a bus service at all, but a willy-nilly aggregation of 350 licensed and 500 unlicensed privately-owned "dollar vans" that roam the streets of Brooklyn and Queens, picking up passengers from street corners where city buses are either missing or inconvenient. The dollar van fleet is a tantalizing demonstration of how we might supplement mass transit to include privately-owned mini-transit entrepreneurs, giving people alternative ways to get around, and creating jobs.

To see how the dollar van universe works (I'll get to why it's illegal in a minute), I spent a morning riding around with one of Brooklyn's dollar van entrepreneurs, Winston Williams of Blackstreet Van Lines. I caught up with Winston's pink, advertising-covered van on Livingston Street in downtown Brooklyn and hopped in the front seat, and off we went up Flatbush Avenue. Almost all of the dollar vans are Ford E350's, with a high body and side doors and enough seats in the back to hold 14 people. Once you notice them in the parts of Brooklyn and Queens where they work, they're ubiquitous. Winston looks in the rear-view mirror and explains that the trick is to keep a distance between the vans in front and the vans behind to maximize the chance of getting passengers. At $2 a ride, he needs to get 14 people in the van on the 5.6 mile trip from downtown Brooklyn to King's Highway to turn a profit. The cost of licensing, insuring, staffing, and fueling the eight vans in his fleet is considerable.

Some people worry that dollar vans pick up passengers who would otherwise ride the bus, but Columbia Assistant Professor of Urban Planning David King and doctoral student Eric Goldwyn say that's not likely. Dollar vans seem to complement the bus service, and they have real advantages. Goldwyn has ridden in the vans and conducted tallies where he's found that on some corners there are four city buses an hour and 45 to 60 vans, meaning that passengers literally don't have to wait more than a minute for a ride. Also, the vans can be a lot faster than public transit. A service that runs between Chinatowns can get from Flushing to Sunset Park in 20 minutes while the subway will take an hour and 13 minutes at minimum. And for regular riders, there are other perks. "I've heard they offer more services -- for example, they'll wait while a parent walks a child up to the door of daycare or a school." That is service that you can't get from a bus.

With its pink advertising wrapping, Winston's van gives the impression that the inside will have a party atmosphere. But it doesn't. The passengers, most of whom are from Jamaica (like Winston) or Trinidad, sit quietly. One Trinidadian woman dressed in business clothes overhears me interviewing Winston and volunteers that vans are a common way to get around the islands. The interior of the van is clean, gray, and institutional -- very much of a piece with Winston's overall business plan to brand his vans and make them mainstream.

He'd like to eventually move beyond the Flatbush route and pick up, say, hipsters in Williamsburg and bring them to Manhattan. If this sounds improbable, it's really not: Think of the incredible popularity of food trucks, which were known as "roach coaches" only 10 years ago. A hip fleet of dollar vans, providing proximity and cheap transit to 20-somethings, could easily catch on. If the vans ran on cleaner engines -- hybrids or natural gas -- they could be part of a greener city. (In another move to raise the profile of his vans beyond Flatbush, Winston allows a music promoter called Dollar Van Demos to film rappers in his vans for broadcast on the Internet.) But no broader growth can happen until the vans can be branded and made attractive to people who don't already know them, says Winston. Ah, and that's where the illegality comes in.

Winston used to have his vans all painted with a green stripe, so they became easily recognized in the neighborhood. While this "uniform" was good for business, his vans also caught the attention of police of various kinds who ticketed him for stopping to pick up passengers, and he accrued fines that ate into profits. This is the paradox of Winston's work: While he is fully licensed, insured, and inspected, his vans are prohibited from doing the one thing they really do -- picking up passengers off the street. David King, from Columbia, quips that all dollar vans are 100 percent illegal (because they work the curbs), but some are 200 percent illegal (because they don't bother to get licensed in the first place). Winston says police don't cite the unlicensed vans, which eat into his business, but do go after the licensed ones for the curb infractions. "The law gets made up as you go along," Winston says, adding that the pink cellphone ad on the van is both an attempt to make a little money as he cruises up and down Flatbush, and a trial balloon to see whether there's a specific law prohibiting advertising on the vans. Later, one of the 500 or so completely illegal vans pulls up beside him, and in friendly Jamaican patois, Winston accuses the driver of being a terrorist. "It's not like I hate against them. But I'm running a business and they're running a hustle," he says.

The existence of laws and the lack of enforcement put the legal drivers in a bind that Winston describes as a Catch 22. In 1993, New York outlawed dollar vans entirely. It took the intervention of some activist van owners with the help of the Libertarian Institute For Justice to get them legalized. Deliberate or not, the city's perverse policy of half-legalizing legal vans and failing to enforce laws against the unlicensed ones limits the growth of what could be a useful transit resource. Winston describes a decade and half of Coyote and Roadrunner exploits with the law, concluding with, "Let there be a train strike, a blackout, a storm, or 9/11, and people are practically tearing the doors off." Last year, when the city was trying to cut bus routes, they even tried to substitute official dollar van routes, but that program was canceled when van drivers were uninterested in the routes, and riders were uninterested in the vans.

You might want to know why, exactly, jitneys or dollar vans are illegal in most states. The answer lies in the history of public transit. Until the early 1950s, most transit systems in the U.S. were privately owned companies that operated as regulated monopolies (like electric utilities today) and expected to provide transit service to an entire city. In exchange, they got the right to be the city's only transit service. Transit ridership peaked during World War II, but the transit companies slid into bankruptcy afterwards, as they were expected to serve greater suburban areas, service declined, and more and more federal money went into highways -- all of which tempted people to buy cars and abandon the trolleys and buses. Most of the country's 200 private transit franchises died in the 1950s. (Roger Rabbit had nothing to do with it. I swear.) In the late 1950s, cities took over the bankrupt transit lines and tried to make a go of them, retaining for themselves the monopoly on the right to provide service. In the early 60s the feds became involved in propping those systems up, but without much enthusiasm. Meanwhile, private transit were prevented from driving the streets even when they offered serviced different from the public transit agencies.

What's interesting about dollar vans, if they're properly licensed and insured -- and reasonably legal -- is that they could gravitate to where the riders are and where they want to go faster than public transit, which requires more infrastructure and meetings. In some cities, bus routes have histories going back decades, and they don't change to reflect how people's lives and work habits have changed. (They certainly don't stop at daycare centers.) Dollar vans are out there to make a buck, and that's not bad for passengers. Here's a video of a valiant dollar van on the prowl for customers during Hurricane Irene, when New York subways were shut down. You can see Winston's pink van at the curb.