Tesla launched its robotaxi service in Austin on Sunday as its Model Y vehicles drove around a select batch of riders who gave rave reviews about smooth, convenient rides that were available for the cheap price of $4.20 .

While no one was in the driver's seat of the Tesla robotaxis, a front-seat rider acted as a "safety monitor" during the trial.

The launch puts Tesla head-to-head with Alphabet-backed Waymo, which is already operating a fleet of robotaxis in several cities.