Washington (AFP)

Travis Kalanick has been the driving force behind Uber, taking a spur-of-moment idea and turning it into the world's most valuable venture-funded tech startup.

But Kalanick's brash personality and freewheeling management style made him a liability as well as an asset to the global ridesharing giant, prompting his decision Tuesday to take an indefinite leave of absence.

Kalanick frequently recounts how the idea behind Uber was born, when he and a colleague were attending a technology conference in Paris and failed to find a taxi on a cold night.

He dreamt up the "magical" idea of pushing a button to hail a ride, the story goes, and used that to create a company that disrupted a global industry while ruffling the feathers of both regulators and established taxi operators.

Uber now operates in hundreds of cities and more than 80 countries, accounting for bookings of some $20 billion last year.

Its valuation has soared to a whopping $68 billion, unprecedented for a startup which has yet to hit the stock market.

But the hard-charging style which helped Uber succeed has also made Kalanick a target for critics.

He has borne responsibility for allegations of sexism, cut-throat workplace tactics and covert use of law enforcement-evading software.

Uber's image has been tarnished by a series of missteps including a visit by executives to a South Korean escort-karaoke bar, an attempt to dig up dirt on journalists covering the company and the mishandling of medical records from a woman raped in India after hailing an Uber ride.

Uber hired former US attorney general Eric Holder to review allegations of a toxic work culture, and adopted his report calling for a series of reforms and safeguards against abuses.

Kalanick has been humbled by recent events, which included the release of a dash-cam video showing him berating and cursing at one of Uber's drivers.

He cited the recent death of his mother in a boating accident as one of the reasons for his decision to step aside.

"For the last eight years my life has always been about Uber," he said in an email to employees Tuesday.

"Recent events have brought home for me that people are more important than work, and that I need to take some time off of the day-to-day to grieve my mother, whom I buried on Friday, to reflect, to work on myself, and to focus on building out a world-class leadership team."

- Being 'disruptive' -

Uber and Kalanick exemplified the notion of being "disruptive," which in Silicon Valley is seen as a positive force for change.

But as it grew into a global company, both the firm and its founder appear to have come to the realization they need to grow up.

"The ultimate responsibility, for where we've gotten and how we've gotten here rests on my shoulders," Kalanick said.

"There is of course much to be proud of but there is much to improve. For Uber 2.0 to succeed there is nothing more important than dedicating my time to building out the leadership team.But if we are going to work on Uber 2.0, I also need to work on Travis 2.0 to become the leader that this company needs and that you deserve."

Kalanick is likely to retain some control of Uber thanks to a structure giving him super-voting shares along with his co-founders.

He was given credit on Tuesday for stepping aside, regardless of whether it was his decision or the result of pressure from the board of directors.

Vivek Wadhwa, a Carnegie Mellon University fellow who follows the tech industry, welcomed his move.

"Leaders need to step aside when they have peaked, learn critical lessons, rethink strategies...and then reinvent themselves," Wadhwa said on Twitter.

Agence France-Presse

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