Monday’s deal between Uber and Volvo could set the stage for a new reality: thousands of autonomous vehicles ferrying customers to their destinations without a human operator. (Aaron Josefczyk/Reuters)

Uber swung one of the largest deals for autonomous vehicles Monday, ordering 24,000 vehicles from Volvo — a move that is expected to advance the case for self-driving cars on American streets.

Passengers can already hail a ride inside a driverless taxi in a small number of U.S. cities — most prominently Pittsburgh — but not without a human operator inside the vehicle. 

Monday's deal between Uber and Volvo could set the stage for something entirely new: thousands of autonomous vehicles ­ferrying paying customers to their destinations without a human ­operator, the beginning of a ­multibillion-dollar robot revolution that could dramatically reconfigure how people get from one place to another. 

Though Uber is refining its self-driving technology, company officials said they expect the first ­robotically driven taxis to appear as early as 2019. 

"We're moving aggressively," Jeff Miller, Uber's head of automotive alliances, said, noting that the company has not decided which cities to begin with. "As soon as the technology is ready, there is a manufacturing machine that is ready to go, and we can push the 'make car' button, and we'll have a clear path to having tens of thousands of self-driving vehicles on the road.

Ultimately, the experiment will depend on the cooperation of ­municipal policymakers, who have sparred with ride-hailing companies such as Uber for years. But Boston as well as several cities in California have been discussing allowing driverless taxis.

The effort also underscores how Uber, which has had several high-profile labor fights with its drivers, is eyeing a not-so-distant future in which driverless vehicles are commonplace.

"This deal is evidence that automated driving is becoming very real," said Bryant Walker Smith, an assistant law professor at the University of South Carolina who focuses on autonomous driving. "It's close enough and it's concrete enough that there are major companies willing to stake their credibility, their strategy and even their survival on this deal."

The agreement — which would allow Uber to buy Volvo's XC90 sport-utility vehicles with autonomous technology from 2019 to 2021 — puts the automaker in an unusual position. It would be selling cars to a company — Uber — whose goal is to dramatically reduce the number of people who own cars. But the auto manufacturer, which is headquartered in Sweden but owned by a Chinese investment group, said it could no longer avoid the inevitable.

"We think its better to be part of potentially disruptive change as opposed to standing on the sidelines and watching it happen," said Marten Levenstam, Volvo's vice president for product strategy. "This will be a major change for the whole auto industry."

While Uber is hoping to get driver­less taxis on the road in 2019, the shift is likely to look like a patchwork of gradual change, as competing companies adapt to regulatory, political and technological considerations in cities around the globe.

Once fully autonomous cars begin operating en masse, the pace will only accelerate, said Jamie ­Arbib, the founder of ­RethinkX, a think tank that forecasts ­technology-driven disruption. 

"These cars learn by doing," he said. "The more miles they're covering, the more experience companies will have adapting to different cityscapes, atmospheric conditions and regulations."

Experts said the partnership between Uber and Volvo probably would spawn partnerships between automakers and Silicon Valley. 

If Uber's self-driving Volvos end up in the United States, Miller said, the company would probably put them in cities where Uber has test fleets, such as San Francisco, Phoenix and Pittsburgh.

Despite the push toward vehicles without drivers, Miller said Uber drivers should not worry about being phased out of the company's long-term plans.

"We have millions of drivers that operate on our platform every day around the world," he said, pointing out that the 24,000 Volvos would be "a fraction" of the Uber vehicles on the road. "There will always be a role for human-driven vehicles. You're going to see a hybrid fleet of human- and robot-driven vehicles."

Arbib said Uber drivers shouldn't worry about getting a new job immediately but should take note of the company's long-term strategy.  

"You'll probably be okay for the next three or four years," he said, "but it would be wise to begin planning for a different long-term future."

Jessica Caldwell, executive ­director of industry analysis at Edmunds.com, said the Uber-Volvo deal is just the beginning of seismic shifts in the industry. 

"We're going to see more and more companies partnering off," she said. "They might know who they're going to homecoming with but not to prom, and it could all implode as strategies change, opportunities arise and everyone looks for the right long-term strategy."