Waymo, the former Google self-driving car project, is stepping up its efforts to get autonomous-driving tech ready for prime time. After an initial trial run in Arizona, Waymo is expanding its fully driverless taxi service featuring Chrysler Pacifica Hybrid minivans.

In a Medium blog post, the company announced, “After more than eight years of development, we’re taking the next step toward unlocking the potential of fully self-driving technology. Starting now, Waymo’s fully self-driving vehicles — our safestmost advanced vehicles on the road today — are test-driving on public roads, without anyone in the driver’s seat.”

Folks in Phoenix will now be able to call a ride in a fully autonomous car, “with Waymo as the sole driver.” Moving forward, the company expects to cover an area larger than the size of Greater London, and of course, more autonomous vehicles will be added as the initiative expands.

Under its “early rider program” trial, Waymo gave selected residents in the Phoenix area 24/7 access to its fleet of self-driving minivans. The initial goal was to get feedback from the public, and to see how the prototype self-driving cars perform in real-world situations. Waymo included hundreds of folks in this initial program, and now, it would appear that things are going better than ever.

Arizona makes a good testing ground because it’s one of a handful of states that has explicitly legalized the testing of self-driving cars on public roads. Uber moved its self-driving cars to Scottsdale after a dispute with the California DMV, although it now tests cars in California as well. General Motors’ Cruise Automation subsidiary also runs self-driving cars on the streets of Scottsdale.

Waymo is also in the process of expanding its the original fleet of 100 Chrysler Pacific minivans to 500. The minivans, which are actually plug-in hybrids, now constitute Waymo’s primary vehicle platform. Under its previous guise as the Google self-driving car project, Waymo used pod-like cars of its own design, and a fleet of converted Toyota Prius and Lexus RX 450h hybrids prior to that.

“The first application of our fully self-driving technology will be a Waymo driverless service,” the company announced. “Over the next few months, we’ll be inviting members of the public to take trips in our fully self-driving vehicles … When fully self-driving vehicles become part of people’s everyday routine, we can move closer to our goal of making transportation safe and easy for everyone.”

Update: Waymo is expanding its fully self-driving car program and will soon launch a taxi service.