Mubasher: Waymo on Wednesday unveiled its first self-driving car service in Arizona, pledging to proceed carefully with the technology.

The service, called Waymo One, would be available to people signed up to the company’s early-rider programme, to which more than 400 residents from Phoenix area subscribed to test drive autonomous cars in their neighbourhood, Alphabet’s self-driving car unit said.

Riders should download a smartphone application and provide a credit card number, the same as ridesharing services Uber and Lyft.

A human driver would be in the driver seat, to intervene in case of emergency.

Some of the volunteers have managed already to ride fully driverless cars, the company said.

The early riders would have access to Waymo One through the application, enabling them to call a Waymo driverless car around the clock, and check estimated prices, based on distance time before they select the trip.

Moreover, the riders would connect with Waymo support through the application.

Up to three adults and a child would be able to ride the autonomous cars, Waymo said.

Waymo expects to “gradually roll out” the autonomous car programme over the future, while the early-rider programme would continue.

“Over time, we hope to make Waymo One available to even more members of the public as we add vehicles and drive in more places,” the firm’s CEO John Krafcik said at the Wall Street Journal’s WSJ Tech D.Live conference.

“Self-driving technology is new to many, so we’re proceeding carefully with the comfort and convenience of our riders in mind,” Krafcik added.

Waymo has been testing its self-driving cars for a decade, as its fleet, currently 600 vehicles, recorded more than 10 million miles on public roads around 25 US cities