Waymo will be expanding its autonomous fleet. In preparation for the launch of its driverless ride-hailing service, Google's self-driving technology company has ordered thousands of self-diving minivans from Fiat Chrysler Automobiles.

Neither Waymo nor FCA has announced the exact number of vehicles that was ordered. However, deliveries are expected to begin in late 2018.

"In order to move quickly and efficiently in autonomy, it is essential to partner with like-minded technology leaders. Our partnership with Waymo continues to grow and strengthen; this represents the latest sign of our commitment to this technology," said FCA CEO Sergio Marchionne.

Waymo and FCA's collaboration began in 2016 when the latter supplied 100 Chrysler Pacifica Hybrid minivans to the former. This was followed by 500 more units last year. The vehicles have been equipped with Waymo software and hardware to enable self-driving capability.

Back in November 2017, Waymo began testing their self-driving vehicles without a driver behind the wheel in the Phoenix suburb of Chandler. This made Waymo the first company to achieve Level 4 autonomy — a technical milestone that many others in the field are hoping to meet.

The self-driving tech company is slated to open its autonomous ride-hailing service to the public in Phoenix, Arizona later this year. The additional minivans will allow Waymo to test its self-driving car technology in other cities across the United States. Just last week, Waymo announced that their autonomous fleet and testing program will be heading to Atlanta next.

"There's a lot of potential for self-driving technology in the region. Local leaders have shown they are committed to innovation and technology, and we're looking forward to testing in the area," a Waymo spokesperson told Fortune.

Apart from Atlanta, Waymo has already tested its self-driving car technology in 24 other cities. This includes San Francisco and Mountain View in California as well as Austin, Texas, Kirkland, Washington, and Detroit, Michigan.