The service kicked off as scheduled aboard Tesla's Model Y vehicles, with customers paying a $4.20 flat fee to ride.

Tesla Inc. shares climbed after the automaker rolled out its long-promised driverless taxi service to a handful of riders, a modest debut for what Elon Musk sees as a transformative new business line.

By Aditya Soni (Reuters) -Tesla shares jumped 10% on Monday after the electric-vehicle maker started testing its long-awaited robotaxi service, a key step toward proving the technology that CEO Elon Musk has for years touted as a crucial driver of its lofty valuation.