The road to autonomous driving is not for the faint of heart. Look behind to view the wreck of Uber’s self-driving car. In the ditch to the left is General Motors’ Cruise robo-taxi. And that scent of burning rubber? That’s from the skid marks Apple made as it careened toward the exit ramp. But one funny-looking vehicle appears to be gaining momentum. Waymo, born 15 years ago as the “Google Self-Driving Car Project,” now offers fully autonomous rideshare services in Phoenix—where its driverless v...