Starting today, Uber riders who request an uberX in San Francisco will be matched with a self-driving, Volvo XC90 Uber if one is available, the ride-sharing company announced.

The move follows the September launch of self-driving Ubers, when the company began allowing customers in downtown Pittsburgh to summon self-driving cars from their phones.

“Expanding our self-driving pilot allows us to continue to improve our technology through real-world operations, Uber wrote in a blog post. “With its challenging roads and often varied weather, Pittsburgh provided a wide array of experiences. San Francisco comes with its own nuances including more bikes on the road, high traffic density and narrow lanes.”

Uber acknowledged there is a debate over whether or not it needs a testing permit to launch self-driving Ubers in San Francisco.

 “We have looked at this issue carefully and we don’t believe we do,” the company said, noting that it does not plan to operate any differently than in Pittsburgh, where its pilot has been “running successfully” for several months. Those rules also apply to cars that can drive without someone controlling or monitoring them. “For us, it’s still early days and our cars are not yet ready to drive without a person monitoring them,” Uber said.

Each SUV will have a safety driver and Uber test engineer onboard to handle manual driving when needed and monitor progress with the tests, TechCrunch reported.