Uber, look out. Google may enter the ride-share game.

Google is reportedly working on its own app-based ride-sharing service to compete with Uber and Lyft, possibly in conjunction with the company’s heralded driverless-car program. The move would put Uber in competition with one of its biggest backers, Google Ventures.

Look out, Uber and Lyft: Google may be in your rear-view mirror.

The tech giant is working on its own app-based ride-sharing service, Bloomberg reported Monday. And it may be in conjunction with the company’s heralded driverless-car program.

The move would put Uber, the mobile service that pairs customers with drivers via their smartphones, in competition with one of its biggest backers. Google Ventures invested $258 million in Uber in 2013 and also was part of a later funding round.

David Drummond, Google’s chief legal officer and a member of Uber’s board of directors, informed that board that the plans were in the works, Bloomberg said, quoting an unnamed source.

Spokespeople for both Google and Uber declined to comment for the Bloomberg article.

Uber, which last week addressed one of its regulatory concerns by offering per-mile insurance for its drivers, might not just lose a major financial backer if Google decides to go it alone in the ride-hailing world. Uber’s app depends upon Google Maps to allow customers to find drivers, and vice versa.

Losing that data would presumably leave the company reliant on one of Google Maps’ competitors, which generally are considered inferior.

Google has made the future of transportation a priority, a fact nowhere more evident than with its driverless-car initiative. Last month, the company unveiled a prototype of one of the cars, which it hopes will be street-legal by the end of the decade.

Since 2011, engineers at Google have put in hundreds of thousands of miles road-testing driverless cars in California, Nevada, Florida and Michigan. Those tests have mostly been in remote areas, but for more than a year now, the company has moved the vehicles onto city streets for more intensive testing.

Perhaps coincidentally, perhaps not, TechCrunch reported Monday that Uber has opened a research facility in Pittsburgh to develop its own self-driving cars. Uber’s CEO, Travis Kalanick, has said publicly that he thinks driverless vehicles are the future and that, when no drivers have to be paid, booking lifts via app will become cheaper than owning a car.

While Google is believed to be far in front of everyone else, several auto manufacturers are also working on self-driving vehicle technology.