SAN FRANCISCO — Uber passengers in Pittsburgh will be able to summon rides in self-driving cars with the touch of a smartphone button in the next several weeks.

The high-tech ride-hailing company said Thursday that an unspecified number of autonomous Ford Fusions with human backup drivers will pick up passengers just like normal Uber vehicles. Riders will be able to opt in if they want a self-driving car, and rides will be free to those willing to do it, spokesman Matt Kallman said.

Uber, which has a self-driving research lab in Pittsburgh, has no immediate plans to deploy self-driving cars beyond the Pittsburgh experiment. But its CEO, Travis Kalanick, has said the ride-sharing company’s future — indeed, the future of all transportation — is driverless.

“When there’s no other dude in the car, the cost of taking an Uber anywhere becomes cheaper than owning a vehicle. So the magic there is, you basically bring the cost below the cost of ownership for everybody, and then car ownership goes away,” Kalanick said at the Code Conference in 2014, shortly after Google unveiled its self-driving car prototype.