A month after Tesla launched a trial robotaxi service in Austin, Texas, in June for select fans, CEO Elon Musk told investors that the company¡¯s driverless taxis would likely be available to ¡°half the population of the U.S.¡± by the end of this year.

Alphabet¡¯s Waymo ¡ª the U.S. leader in autonomous ride-hailing ¡ª launched a similar test service in Phoenix more than eight years ago. Today, it operates in areas with about 3% of the U.S. population.

Musk¡¯s pronouncements about expanding Tesla¡¯s robotaxis at a ¡°hyper-exponential rate¡± stand in contrast to Waymo¡¯s deliberate approach ahead of entering new markets. Musk sees a faster path to scaling the business because of Tesla¡¯s reliance on just cameras and artificial intelligence, compared with Waymo¡¯s rules-based AI approach that uses more sensors and high-definition mapping. The differing strategies have far-reaching implications for the early pecking order in the nascent autonomous-driving space, which some analysts and investors say could become a multitrillion-dollar market over the next 15 years.