(Reuters) -Tesla has started testing robotaxis with passengers in Austin, Texas, CEO Elon Musk said on Sunday, with customers paying a flat fee of $4.20, as the electric vehicle maker looks to roll outthe much-anticipated service and gain a foothold in the self-driving technology race.

(Reporting by Reporting by Akash Sriram and Chandni Shah in Bengaluru; Editing by Alan Barona, Rod Nickel and Chris Reese)