Travis Kalanick was 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, and on Wednesday he stepped down as chief executive. 

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.

In a statement, Kalanick said he loved Uber "more than anything in the world" but had agreed to investors' request for him to quit.

- 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.

Kalanick retains a seat on the board and is likely to retain some influence thanks to his substantial holding of shares in the company.

Source: AFP