Uber is in the race to develop a fully self-driving system to one day power a fleet of driverless taxis.

To develop the system, Uber is using a fleet of Volvo XC90 SUVs fitted with all the necessary hardware required for self-driving capability, such as cameras and sensors. The vehicles also incorporate necessary safety and redundancy systems to handle emergency situations.

Volvo has been installing the hardware on XC90s supplied to Uber since August 2016. On Monday, the two companies announced that Volvo will supply as many as 24,000 of its XC90s to Uber between 2019 and 2021.

Uber is using the vehicles to develop the complex software that crunches the incoming data from the sensors to make instructions that then control the vehicle. Uber has been conducting most of its testing in Pittsburgh, Pennsylvania, although the company’s test fleets have also taken to roads in Arizona and California.

Uber self-driving prototype in San Francisco

Uber self-driving prototype in San Francisco

Uber has no intention to manufacture its own cars for its future driverless taxis. Instead, it will purchase them from established automakers such as Volvo. It’s not clear when there will be driverless taxis on the road but many in the industry give a timeline of 5-10 years.

“This new agreement puts us on a path towards mass produced self-driving vehicles at scale,” Jeff Miller, Uber’s head of auto alliances, said in a statement.

Volvo is working on its own self-driving system in a partnership with Swedish supplier Autoliv. Volvo says it will have a car capable of driving itself on its own in certain conditions on sale by as early as 2021. To help develop its self-driving system, Volvo launched the Drive Me project where project where 100 self-driving prototypes are being handed over to regular customers in Gothenburg, Sweden, the automaker’s hometown. In certain sections of Gothenburg, the prototypes are able to operate in full autonomous mode.

“The automotive industry is being disrupted by technology and Volvo Cars chooses to be an active part of that disruption,” Volvo CEO Håkan Samuelsson said in a statement. “Our aim is to be the supplier of choice for [autonomous drive] ride-sharing service providers globally.”