Alphabet’s self-driving technology company, Waymo, is giving hundreds of Phoenix-area residents access to their own autonomous vehicles, initiating one of the largest and most public efforts yet to put ordinary people inside cars of the future.

The race to perfect self-driving cars is taking on greater urgency as tech companies and automakers alike pour billions of dollars into developing the systems and push them onto America’s roadways alongside human drivers.

Waymo isn’t just offering people the occasional ride, the company said. Instead, participants accepted into its “early rider program” and their immediate family members will use either a self-driving SUV or minivan as their primary or secondary vehicle at no cost.

The Waymo vehicles will have safety drivers to monitor rides at all times.

The company plans to collect real-world information about how people use the cars as they move about their daily lives. But the vehicles won’t be parked in driveways. Participants will have to summon them for each ride, much as industry leaders expect people will do when self-driving cars are eventually used in ride-sharing fleets.

“We’ll learn things like where people want to go in a self-driving car, how they communicate with our vehicles, and what information and controls they want to see inside,” Waymo chief executive John Krafcik said in a blog post on Medium.

The program marks a significant step forward for Waymo, which began in 2009 as Google’s self-driving car project. The company first allowed a non-employee to travel solo in one of its cars in 2015, but did not make the trip public for more than a year.

No longer a science-fiction pipe dream, cars that drive themselves could be a trillion-dollar business, analysts predict, and that has drawn in some of Silicon Valley’s heavyweights. Uber began offering rides to regular passengers in Pittsburgh last year and has since expanded to Phoenix and San Francisco, where its initial plans to test self-driving vehicles ran afoul of state regulators.

Earlier this month, Apple obtained permits from California state regulators to begin testing up to three self-driving cars on the roads there.

Automakers aren’t sitting idle. General Motors plans to deploy thousands of self-driving cars through the ride-sharing company Lyft next year, according to Reuters. Ford invested $1 billion earlier this year in the autonomous vehicle company Argo AI.

Tesla already makes cars equipped with auto­pilot technology capable of driving the car under certain circumstances.

The competition for technical talent has led to clashes among companies. Uber and Waymo, for example, have been locked in a legal battle over disputed intellectual property, which Waymo alleges was stolen by a former employee that Uber later hired.

As California puts the final touches on the nation’s most far-reaching rules on autonomous cars, other states, including Arizona, are presenting a more permissive regulatory environment. California says its rules would allow a car to run with no driver present by year’s end, something that is already allowed in Arizona and some other states.

The Department of Transportation last year asked tech and automotive firms to submit voluntary safety letters as part of their driverless initiatives, but refrained from imposing regulations, saying they did not want to stymie innovation.

Industry observers have raised questions about how the vehicles will fare on roads, especially when dealing with unpredictable human drivers. A self-driving Uber was involved in a traffic collision earlier this year, though another vehicle was deemed at fault.

Exposing people to self-driving vehicles will be key to winning over skeptical riders, many of whom may hesitate to entrust the technology with their lives, experts say.

Waymo also announced it would expand its fleet of self-driving Chrysler Pacifica Hybrid minivans from 100 to 600 in the coming months.

A promo video for the early rider program features a family of six who lament the transportation ills of most large families: rush-hour commutes, constant rides to sports practices and music rehearsals, teen drivers seeking independence on the road. They see self-driving cars as a possible solution.

“Our early riders will play an important role in shaping the way we bring self-driving technology into the world — through personal cars, public transportation, ride-hailing, logistics and more,” Krafcik said.

Waymo is accepting applications for the free program, which will ultimately include “hundreds of people with diverse backgrounds and transportation needs,” Krafcik said. Applicants must be at least 18 years old, and the program would initially include the Phoenix area communities of Chandler, Gilbert, Mesa and Tempe. Plans to expand the program to other cities would be forthcoming, the company said.