Waymo, the self-driving car division of Google LLC parent company Alphabet Inc., today announced that it has started testing ride-hailing services with autonomous vehicles that don’t have a safety driver behind the wheel — the first time this type of service has been offered in the United States.

The test is an extension of a trial in the greater Phoenix area it announced in April. The driverless self-driving cars have been deployed as a subset of the company’s fleet with “Waymo as the sole driver.” However, initially a Waymo employee will be in the back seat of the vehicle just in case something goes wrong for the first few months. Later no company employees will be in the vehicles at all.

Emphasizing that the new test is completely safe, Waymo wrote in a post on Medium that it’s launching the test after putting the vehicles through “the world’s longest and toughest ongoing driving test.” That included 3.5 million autonomous miles on public roads, 10 million miles every day in simulation and 20,000 individual scenario tests on the company’s private track.

Hinting at previous rumors that Waymo may be preparing to deliver commercial services using the technology, the same post noted that the technology allows the company to “reimagine many different types of transportation, from ride-hailing and logistics, to public transport and personal vehicles, too. By giving people access to a fleet of vehicles, rather than starting with a personal ownership model, more people will be able to experience this technology, sooner.”

The new service is still restricted to those already selected by Waymo to participate, but the company said it expects to open up the program to more participants in coming months. Expansion plans outside Phoenix were not mentioned, but with the company having recently announced that it had started testing autonomous vehicles in Michigan, the Phoenix test could be the start of Waymo’s first commercial service.

That service would likely compete with both Lyft Inc. and Uber Inc. The former may end up using Waymo technology in its fleet, while the latter struggles with the development of self-driving car technology.

Photo: Waymo