Tesla's Cybercab, or robotaxi, was announced last October and is due to hit the roads in Texas this June as part of a trial roll-out.

The Uber logo is displayed on a car on March 22, 2019 in San Francisco, California. - Image: Justin Sullivan / Staff () Uber CEO Dara Khosrowshahi would rather work wi

Musk, who also runs SpaceX and a number of other companies, has been known to make big often exaggerated promises. For example, he once called the Hyperloop, which was never built, the "fifth mode of transport" and famously promised to take Tesla private in a Twitter post, saying he had secured financing that he didn't have.