Avis is already there. They handle the fleet maintenance and storage of Waymo's self-driving cars for Waymo's Phoenix testing.[1] When one breaks down, Avis sends the tow truck.

Avis already owns Zipcar, so they have app-based car services already deployed. So as soon as the technology is ready, Avis is there with the customer base and the infrastructure.

[1] https://www.bloomberg.com/news/articles/2017-06-26/alphabet-...