For years, Google — which recently renamed its self-driving car division “Waymo” — has been viewed as having the industry’s leading self-driving car technology. In the past couple of years, Waymo has had dozens of cars on the road racking up more than 2 million miles of real-world driving experience.

Now Waymo is taking the next step: opening its testing program to members of the general public. People in the Phoenix area can apply for access to Waymo’s new testing program. In a Monday blog post, Waymo CEO John Krafcik says that “hundreds” of families will be accepted into the program. Families need to apply to participate. The lucky ones chosen by Waymo will get to take unlimited rides for free.

Waymo already has a fleet of 100 Chrysler Pacifica Minivans, and the company is ordering 500 more to support the new riders. The goal is not only to get feedback from these new customers, but also to gather more real-world data about the road conditions and challenges self-driving cars face when traveling around on real city streets. The minivans will have a Waymo employee in the front seat ready to take over if the self-driving software gets into trouble. Eventually, Waymo’s hope is to eliminate these safety drivers, but the company hasn’t said how long that will take.

The announcement also seems to confirm that Waymo is planning on pursuing an Uber-style ride-hailing model rather than selling cars to customers outright. One big advantage of this is that Waymo can roll out its service gradually, one metropolitan area at a time. Phoenix is an ideal starting point because cars in Phoenix rarely encounter rain, snow, or icy roads. Once Waymo has mastered driving in this relatively forgiving terrain, it can tackle driving through drizzle in Seattle or on icy roads in Minneapolis.