SAN FRANCISCO (AP) — Google's self-driving car spinoff Waymo is teaming up with Lyft in Arizona to attempt to lure passengers away from ride-hailing market leader Uber.

The alliance announced Tuesday will allow anyone with the Lyft app in the Phoenix area to summon one of the 10 self-driving Waymo cars joining the ride-hailing service.

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Waymo's robotic vehicles will still have a human behind the wheel to take control in case something goes awry with the technology. But their use in Lyft's service could make more people feel comfortable about riding in self-driving cars.

Both Lyft and Uber consider self-driving cars to be one of the keys to turning a profit, something neither company has done so far.

The new threat to Uber is emerging as the company prepares to go public this week.