Lyft and Waymo have partnered up to launch a robo-taxi fleet in Arizona.

Waymo’s self-driving cars will become available to Lyft customers in Phoenix in the coming days.

According to Waymo, the cars will be fully autonomous, but they will be operated by safety drivers who will take over should anything go wrong during a ride. This announcement comes almost alongside Lyft’s Q1 earnings report. This new partnership has come at a critical time for Alphabet subsidiary Waymo, which launched the ride-hailing product “Waymo One” in Phoenix just four months ago.

Customers in Phoenix will have the option to select a Waymo autonomous vehicle directly from the Lyft app. This technology is certainly still in the testing/introductory phases, but the results will be important for the future of ‘robo-taxis.’