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.

Tesla told U.S. regulators that its answers to questions on the safety of its robotaxi deployment in Texas are confidential business information and should not be made public, according to a letter released on Monday.