On a recent trip to Washington, D.C., I booked a ride through Uber, the popular ride-sharing network. My driver was a retired social worker. He told me that he’d gone to work for Uber after eight fruitless months pursuing an official taxi license. Uber had approved his application within a few days.

Transportation network companies (T.N.C.s), like Lyft, Sidecar, and UberX, rely on smartphone apps to link customers with rides. They have a pool of semi-professional drivers composed, in part, of college students, the unemployed, and retirees. The fight between the upstart T.N.C.s and the taxi industry has been pitched in ideological terms: free-market innovation versus old-guard competition-killing regulation. In reality, it’s a labor war, and it has destabilized the core of what it means to be a professional driver.

The driving trade has always attracted both experienced professionals and part-timers who fill in the cheaper end of the market. In London, for example, licensed black-cab drivers distinguish themselves by mastering what’s known as the Knowledge—a compendium of city street routes that dates back to 1865. British cabbies must commit the Knowledge to memory before they’re allowed to accept fares. On average, the licensing process takes about five years to complete and includes a written test and one-on-one interviews in which prospective drivers are asked to navigate between two points in the city. Neuroscientists from University College London found that people who undergo this training and work as licensed cab drivers have larger than usual posterior hippocampi, the area of the brain responsible for spatial memory. The researchers concluded that the process of obtaining a license and maintaining the mental acuity to navigate the city helped London’s cab drivers develop their brains beyond normal capacities.

Of course, not all cab drivers are as knowledgeable as those in London. In New York, driving a yellow taxi has historically been a short-term gig. Allan Fromberg, a spokesman for the New York City Taxi & Limousine Commission (T.L.C.), told me, “One would be hard-pressed to find a cabdriver who wasn’t part-timing in the sixties.” The temporary nature of cab driving meant that some drivers knew very little about the city. In 1969, the Times reported that one driver, a nineteen-year-old pre-med student who drove a yellow cab in the summer, had to pull up beside another cab to ask how to get to Times Square.

Since the seventies, New York City has enacted numerous fare increases and focussed more attention on driver training. The T.L.C. recently partnered with the City University of New York to provide a uniform curriculum for all yellow-taxi and for-hire drivers seeking licensing from the city. It encompasses geography, an overview of the T.L.C. rules, and guidance on dealing with passengers. It’s nothing like the Knowledge, but “there is an interest in a higher professional standard in New York,” Fromberg said. Bhairavi Desai, the executive director of the New York Taxi Workers Alliance, told me, “Customer complaints and accidents are at an all-time low.”

Startups like Uber argue that technology can transform the casual driver into a professional. With G.P.S., anyone can navigate efficiently. Real-time passenger feedback means that drivers who consistently receive low ratings can be dropped from the service. “Tech tools have changed the whole environment,” Josh Mohrer, the general manager of Uber’s New York office, told me. The upstarts can provide a range of ride options at different price points, improve driver efficiency by matching drivers with rides more quickly, and weed out bad drivers. Ride-share services allow drivers to avoid acquiring expensive New York City taxicab medallions, which grant drivers the right to operate yellow cabs. (Medallions come on the market infrequently; earlier this year, one was auctioned off for nearly a million dollars.)

This is how Uber and others are destabilizing the industry. It has experienced similar upheaval before. “Forty years ago, drivers went from laborers to independent contractors,” Desai explained. In the seventies, corporations lowered costs by hiring contract labor and leasing medallioned cabs to drivers. As contractors, drivers lost basic labor protections, like health insurance and paid vacations. Ed Rogoff, a professor at Baruch College’s Zicklin School of Business (and a former New York City cab driver), told me, “The independent-contractor taxi model is like sharecropping. Previously, cabbies and garage owners split proceeds fifty-fifty, with drivers keeping tips. The new system totally changed the structure of the industry by shifting all of the risk to the drivers.” The erosion of labor’s strength, Desai argues, explains the industry’s vulnerability to companies like Uber.

As bad as the shift to being independent contractors was for drivers, labor leaders argue that the ascendance of ride-sharing outfits will be even more painful. If the market is flooded with part-timers, few cities will be able to maintain a fleet of trained drivers who can make a living driving cabs. Speaking of the drivers her union represents, Desai said, “If the Ubers of the world are successful, we’ll be reduced to nothing.”

There is now talk within the taxi community of developing mobile applications to compete with the T.N.C.s. Desai sees this as a viable strategy, one that could stitch together the obvious benefits of technology and professionalism. “In cities where ride-share has grown, it’s because professional taxi drivers have switched to the other side,” Desai explained. “The Uber model isn’t sustainable without professional drivers.”

Photograph: Christopher Anderson/Magnum.