Waymo autonomous cars are available for anyone traveling within downtown Phoenix to and from Sky Harbor International Airport starting Friday, and "nearly all" of the vehicles carrying paying customers will have no backup driver behind the wheel, the tech company announced.

Waymo, an affiliate of Google, has incrementally expanded its self-driving car business throughout metro Phoenix for years and has two service areas, one in the East Valley and one in the downtown Phoenix area.

Last month the company announced that select customers in its "Trusted Tester" program could get airport service.

Friday's announcement not only opens that service to anyone who wants a driverless car ride but also includes nearly doubling the size of the Phoenix service territory.

All service to the airport will use Sky Harbor’s 44th Street PHX Sky Train Station for pickup and drop off, and can only connect to Waymo's Phoenix service area, for now, not the Mesa-area service territory.

The Phoenix service area runs from about Interstate 17 east to State Route 143 and from the airport north to Camelback Road, according to a map provided by the company.

Waymo is bringing a commensurate number of additional vehicles to the region to begin serving anyone who downloads the smartphone app, though the company only will disclose it has "hundreds" of cars serving Arizona.

The Phoenix territory uses Jaguar I-PACE vehicles exclusively, while the East Valley area uses those as well as minivans.

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The Waymo One ride service works much like Uber or Lyft, except the vehicles are uniform and guided by radar, lidar, cameras and the company's technology. Pricing for rides is similar among the services.

Launching service to an airport is a major first for Waymo, which actually hosted a media call on the issue rather than communicating to the press via news releases and emails as is often custom for it and other tech companies that closely control their messaging.

Waymo on Friday also announced an expansion of its services in San Francisco. Its offerings are more limited in that city.

Can driverless cars handle chaotic airport traffic?

Waymo refers to its technology as its "driver," and officials said they are confident their technology is ready to handle airport traffic and driving situations.

“We’ve tried to build a driver with immense amounts of experience and prioritizing safety,” Saswat Panigrahi, chief product officer for Waymo, said on a Wednesday call with reporters. "Think of a driver that can drive well in the dense, narrow parts of San Francisco and in the high-speed roads of Phoenix, and the combination of speed and density in downtown Phoenix, and deal with an airport. That is a pretty capable driver."

When asked if there would be enough cars available during periods of high demand, Panigrahi explained one of the benefits of using robotaxis over human drivers to manage its fleet.

“Our driver won’t have an opinion when we tell them to go to the airport," he said.

He said that when people see Waymo vehicles operating in Arizona with safety drivers behind the wheel, that is an indication they are testing new software or hardware. He said nearly all Sky Harbor rides will be fully autonomous without a driver.

Phoenix Mayor Kate Gallego was scheduled to ride in one of the vehicles to the airport to coincide with the announcement.

“Phoenix is leading the future of mobility and modernizing how the world will experience travel,” Gallego said in a prepared statement. “The exciting technology offers our customers an additional option for traveling to the airport in a clean, sustainable and technologically advanced mode of transportation. The future has arrived in Phoenix!”

Reach reporter Ryan Randazzo at ryan.randazzo@arizonarepublic.com or 602-444-4331. Follow him on Twitter @UtilityReporter.

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This article originally appeared on Arizona Republic: Waymo offers driverless rides to Phoenix Sky Harbor airport for all