SAN FRANCISCO — Waymo is launching fully driverless vehicles to the public, a milestone achievement for Silicon Valley’s self-driving car industry that comes during a global pandemic in which efforts to limit person-to-person contact have found a welcoming audience.

The company, a part of Google parent Alphabet, said Thursday it is opening up its driverless ride-hailing service to riders in the Phoenix metro area, enabling anyone in the region to download its app and hail a ride without a driver in the front seat. It follows an extended public trial for the company’s ride-hailing service in which riders were able to use it for commutes, grocery runs and routine tasks, such as bringing their kids to school. During that launch period, Waymo said, it gradually expanded its service and the capabilities of its vehicles — the vast majority of which were monitored by human drivers. Waymo spokeswoman Katherine Barna said the company was giving between 1,000 and 2,000 weekly rides before the coronavirus pandemic, 5 to 10 percent of which were fully driverless.

The company shut down its service earlier this year because of the pandemic. But “we expect to reach and exceed that volume as we ramp back up,” Barna said.

Previously, driverless trips were offered only to an exclusive group of early adopters. But in “the near term, 100% of our rides will be fully driverless,” Waymo CEO John Krafcik wrote in a blog post announcing the move.

Waymo said driverless service would initially be offered to existing users of its Waymo One ride-hailing app, but the service would be expanded to the broader public “over the next several weeks.”

Companies across Silicon Valley are racing to make self-driving cars a reality, a technological moonshot that would make the economics of ride-hailing much more lucrative by sparing the expense of human drivers. So far, progress has been slow as companies have delayed their rollouts and extended their timelines, confronted by the challenge of programming cars to respond to the near-infinite stream of scenarios a driver could face. The pandemic threw a further wrench into the companies’ plans.

Waymo has long been seen as the industry leader in the space, trailed by competitors such as ride-hailing services Uber and Lyft, Amazon-acquired Zoox, General Motors’ Cruise and automakers pursuing autonomy, such as Tesla.

So far, companies have taken testing of self-driving vehicles to states with varied geographic landscapes and climates to see how they react in a variety of situations. Prominent pilots have rolled out, for example, in California, Pennsylvania and Michigan.

Arizona’s lax regulatory landscape and arid climate have made it a haven for driverless vehicles. But the experiments have not been without incident. In 2018, a self-driving Uber fatally struck a pedestrian crossing a darkly lit street with her bicycle in Tempe, Ariz. The driver monitoring the car was looking at her phone, authorities said.

Waymo relied on a process including a “rigorous review of our safety readiness” before making the decision to launch driverless cars to the public, Barna said. The company informed the state’s transportation department of its testing plans before the announcement, she said.

Krafcik said the company will gradually roll out its driverless service in the region, beginning with those who are already part of its self-driving car service, Waymo One.

“Later this year, after we’ve finished adding in-vehicle barriers between the front row and the rear passenger cabin for in-vehicle hygiene and safety, we’ll also be reintroducing rides with a trained vehicle operator, which will add capacity and allow us to serve a larger geographical area,” he wrote.

Waymo said it cleans its vehicles multiple times throughout the day, in addition to temperature-screening its maintenance workers and regularly flushing the cars’ cabin air through their climate control systems. The cars are also remotely monitored “to make sure they are meeting our high standard of cleanliness,” the company said on its website.

“If we have a reason to suspect otherwise, the vehicle returns to our facilities immediately for a full cleaning and disinfection,” Waymo added.