Google's Waymo said on Tuesday it will soon start chauffeuring people in minivans without "safety drivers," staffers that man the steering wheel.

Starting now, Waymo's fully self-driving vehicles are test-driving on public roads, without anyone in the driver's seat. To date, Waymo vehicles have been operating on public roads with a test driver at the wheel. Now, in an area of the Phoenix metro region, a subset of WAymo's fleet will operate in fully autonomous mode, with Waymo as the sole driver. Over time, Waymo will cover a region that's larger than the size of Greater London.

Waymo says that all of its vehicles are equipped with the "unique safety features" necessary for full autonomy, including backup steering, braking, computer and power that are capable of bringing the vehicle to a safe stop, if needed.

"We want the experience of traveling with Waymo to be routine, so you want to use our driver for your everyday needs," John Krafcik, Waymo's chief executive officer, said at the Web Summit conference in Portugal. "Fully self-driving cars are here."

Krafcik said a Waymo service will arrive soon, allowing people to hail the cars with a mobile app, similar to services like Uber and Lyft. Waymo has partnered with Lyft but hasn't shared details on that deal.

The state of Arizona has no restrictions on self-driving cars. Some U.S. states have existing laws that require a human to be in the driver's seat of a vehicle, although Waymo and other companies have lobbied against these. Last month, California regulators peeled back that rule in the state.