https://www.cnet.com/roadshow/news/waymo-self-driving-app-google-play-android-launch/

After signing up in Waymo's app, you're placed on a waitlist. At that point, it's up to Waymo to promote you from the waitlist to the real-deal Waymo One service. Once you've moved on up, though, you'll be able to request a ride in one of Waymo's autonomous vehicles within the predefined area within Phoenix where the service operates.

Waymo One operates using a fleet of self-driving Chrysler Pacifica minivans. For the time being, there's still an operator in the front seat for safety's sake, but Waymo said it may add true driverless vehicles to the fleet in the future. The vehicles are outfitted with additional hardware to help riders feel at ease, including screens that display the route and buttons for pulling over or calling Waymo's helpdesk. Roadshow's own Tim Stevens took a ride when the service launched in December, and he found it met his admittedly high expectations, but members of the public have been invited to take rides in Waymo's cars as far back as April 2017.