Waymo, the autonomous car company owned by Alphabet – parent company of Google – has begun offering free rides to the public in a new fleet of self-driving minivans.

The Chrysler Pacifica is Waymo's vehicle of choice for the trial, which is referred to by the company as an "early rider program" and is running to help establish how driverless, on-demand cars will become a part of people's everyday lives.

Like a similar autonomous taxi trial being run by Uber, the Waymo vehicles will have a test driver in the driver's seat at all times, ready to take over should the autonomous system need help.

Potential customers can sign up to the service as long as they live in the greater Phoenix area of Arizona; driverless rides will operate in an area twice the size of San Francisco, Waymo says, covering Gilbert, Tempe and Chandler. Customers wanting to try the service, which is free for now, can apply on the company's website.

Waymo is looking to work with customers who are willing to use the autonomous minivans as their primary mode of transport. To ferry as many people as possible during the trial, Waymo has ordered an additional 500 Pacifica minivans from Fiat Chrysler, to be fitted with laser guidance systems and join an existing fleet of 100, which have been in use in Phoenix and Google's native Mountain View, California, since 2016.

Waymo chief executive John Krafcik said the service is looking to transport hundreds of customers. He added: "Rather than offering people one or two rides, the goal of this program is to give participants access to our fleet every day, at any time, to go anywhere within an area that's about twice the size of San Francisco." The cars will be coming to more communities soon, he added.

"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. Self-driving cars have the potential to reshape each and every one of these areas, transforming our lives and our cities by making them safer, more convenient and more accessible."