Waymo is launching a ride hailing service pilot in Phoenix, Arizona, following a recent demonstration of its vehicles driving without any humans onboard. The service seems necessary to prove the safety of a driverless ride hailing service to regulators and potential users of the Waymo system – but could also mark its first move into the ride-hailing business, and the potential for its expansion should deeply concern market incumbents Uber and Lyft. Waymo boss John Krafcik wrote that in the metro region of Phoenix, a subset of the fleet will operate in fully autonomous mode without a safety driver – meaning that the autonomous Waymo system is the sole driver of the vehicle. A simple app hails the cars, and…