Cruise, the autonomous vehicle company backed by General Motors, is now officially a commercial service. The company began charging for rides in its self-driving taxis in San Francisco this week, marking an important milestone for the company’s plans to expand its service.

The company said that fared driverless rides are currently taking place with “most riders” in the Northwest section of San Francisco. Cruise will continue “expanding our paid service in alignment with the smoothest customer experience possible,” a spokesperson said.

Cruise currently offers a range of services, from daytime rides in its autonomous vehicles with safety drivers behind the wheel to nighttime trips in its fully driverless cars. (The company is currently prohibited from offering rides in its driverless vehicles during daytime hours.) Cruise has been testing free driverless rides for the public in San Francisco since February.

The cost for riding in one of Cruise’s driverless vehicles will vary depending on the length of the trip and the time of day. According to an example provided by the company, a customer taking a 1.3-mile trip would pay $0.90 per mile and $0.40 per minute, in addition to a $5 base fee and 1.5 percent city tax, for a total of $8.72. (By comparison, an Uber ride for the same trip would cost at least $10.41.)

Cruise is also now allowing riders to bring a guest on their trip (previously, rides were limited to just the account holder). And the company’s “Cruise — Driverless Rides” iOS app is now available in the Apple App store via an invite code to riders who have previously signed up for the public waitlist.

Driverless cars are still a long ways away from the ubiquity and convenience of most ride-hailing services. But the progress in offering fared rides is still noteworthy. Cruise is not the first to charge a fee for rides; Waymo, a spinoff from Google, has been charging for rides in its driverless vehicles in Phoenix, Arizona, as well as for rides in its drivered vehicles (autonomous vehicles with safety drivers) in San Francisco. The company has yet to receive final approval to charge riders for trips in its driverless vehicles in the city.