Uber’s self-driving car program has been adrift sincea fatal crashin March, but the ridesharing company may have just gotten a lifeline. Toyota will invest $500 million in Uber, and the two companies will work together on deploying autonomous cars in pilot ridesharing programs by 2021.

Under the partnership, Uber autonomous-driving tech and Toyota’s own prototype Guardian system will be integrated in Toyota test vehicles. These vehicles will operate in pilot ridesharing services on the Uber network.Toyota believesservices like Uber will be the main users of self-driving cars, rather than individual owners.

2018 Toyota Sienna

The fleet of self-driving cars will be modified Toyota Siennaminivans. Uber currently uses Volvo XC90 SUVs as test vehicles, and had plannedto buy thousands of themas part of an effort to scale up its autonomous-car program. It’s unclear what will happen with the Volvo deal now that Uber is working with Toyota, but it’s possible the company will use cars from multiple manufacturers. Rival Waymo currently usesChrysler Pacifica minivans, but will soonadd the Jaguar I-Paceelectric car to its fleet.

Toyotahas already donesome self-driving development work in-house, including the creation of two prototype systems. Guardian only intervenes when it thinks the human driver needs help, while Chauffeur takes complete control. Toyota even built a test vehiclewith two steering wheelsto study the process of handing off control from human to machine.

Uber was a leader in self-driving cars, but has lost ground in the wake of a fatal crash. In March, an Uber test vehicle struck and killed a pedestrian while she was pushing a bicycle across a street in Tempe, Arizona. Uber suspended testing andwithdrew its autonomous carsfrom Arizona, but said it would eventually resume testing in Pittsburgh, Pennsylvania. That hasn’t happened yet, and in the meantime Uber has scrapped itsself-driving truck program.

The crash came roughly a month after Uber settleda trade-secrets lawsuitwith Waymo, in which the Alphabet unit accused Uber of using information stolen by engineer Anthony Levandowski. Waymo has since accelerated its plans for deploying autonomous vehicles, starting aself-driving truck pilotand announcing plans to launch an autonomous ridesharing service in Arizona before the end of the year.