A futuristic fleet of driverless cars is about to hit the streets of Pittsburgh. Bloomberg reports that Uber will begin adding autonomous Volvo XC90s to their Pittsburgh fleet this month, though for now, each autonomous car will be supervised by a human driver.

Customers will be able to book the driverless Uber rides as they would any other, using the Uber app on their mobile devices. But unlike the average Uber ride, the autonomous cars will come with a serious discount: Instead of the $1.30 per mile Uber normally charges in Pittsburgh, all autonomous Uber rides will be free—at least to start.

The high-tech custom Volvo XC90s are equipped with lasers, cameras, radar, and GPS, which will let them navigate independently and avoid collisions. Uber has been working for the last year to map the entire city of Pittsburgh down to the last pothole, which will, in some cases, allow their autonomous cars to achieve location accuracy within an inch. However, parts of Pittsburgh have proven easier to map than others, and human oversight will still be necessary in areas where autonomous cars rely on GPS over their own mapping system. Bridges, in particular, give the driverless cars trouble, since they offer few environmental cues.

In addition to the trained engineers who will sit in the driver’s seat and occasionally take the wheel, Uber has hired co-pilots to sit in the front passenger’s seat and take notes on everything that happens. Customers, too, will be expected to give feedback, and will be provided with a tablet in the back seat on which to give notes.

While Uber will likely employ human supervisors for their driverless cars as they continue to refine their technology, the company sees the Pittsburgh experiment as an important first step in making the technology mainstream. “We are going commercial,” Uber co-founder Travis Kalanick told Bloomberg. “This can’t just be about science.”

[h/t Bloomberg]