Zoox Inc., a secretive Silicon Valley startup that is developing its own self-driving vehicles, has raised an additional $50 million from Composite Capital Management on a valuation of $1.55 billion, according to The Wall Street Journal.

Founded in 2014 by Australian entrepreneur Tim Kentley-Klay and Jesse Levinson, from Stanford University’s self-driving car program, the company is said to be developing a fully automated, self-driving electric vehicle fleet and a supporting ecosystem for the vehicles that would allow them to bring the service to market at scale.

Much of what is known about the company is speculative or has come from off-the-record media leaks, because its website provides zero details about what they are doing. But it is believed that Zoox is not attempting to build vehicles for sale to the public, rather attempting to take on Uber and by extension the taxi industry, by delivering in each market a sizable fleet of self-driving custom-built vehicles designed specifically for the role.

According to TechCrunch, Zoox may launch in beta into some markets next year, although that’s presuming it can overcome regulatory hurdles for self-driving vehicles, which in most places requires an operator behind the wheel of the car, let alone a steering wheel itself.

“At Zoox what we’re creating … is not a self-driving car any more than the automobile is a horseless carriage. We’re not building a robo-taxi service, we’re actually creating an advanced mobility service,” Kentley-Klay is reported to have said in October. “You can really think of it as Disneyland on the streets of perhaps San Francisco and that means a vehicle which is smart enough to understand its environment but it’s also importantly smart enough to understand you, where you need to be, what you want to do in the vehicle and how you want to move around the city.”

The new money invested in Zoox highlights the continued growing interest in self-driving vehicle technology, which at its forefront includes tech companies Alphabet Inc. (Google Inc.), Uber Technologies Inc. allow with car makers Tesla Motors Inc., General Motors Corp. and the Ford Motor Co., to name a few.

Including the new money, which was an extension of their initial Series A round, Zoox has raised $290 million to date with previous investors including AID Partners Capital, Blackbird Ventures, Draper Fisher Jurvetson and Lux Capital.

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