General Motors‘ autonomous driving unit Cruise has started charging fares for driverless rides in San Francisco, the company said on Thursday, a step towards commercialization of the service.

Cruise earlier this month became the first company to secure a permit to charge for self-driving car rides in the U.S. city, after it overcame objections by local officials.

Self-driving test cars with human safety drivers have become a constant sight in San Francisco, and completely driverless ones are increasingly common too. Turning them into a fledgling business in a major U.S. city marks a milestone in the long, delayed journey toward driverless taxi service.

The fared driverless rides are currently taking place in the northwest third of the city, the self-driving tech firm said on Thursday, adding that it would expand the service.