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Over the last year, Uber actively courted a number of automakers and autonomous tech startups — including both General Motors and the carmaker's newly acquired startup Cruise — to help the company advance its autonomous efforts, multiple sources close to the matter told Recode.

Uber didn't discriminate when it came to seeking partnerships and approached every player, including Ford, sources said.

Developing self-driving cars has long been an ambition for Uber CEO Travis Kalanick. And today, the company announced an investment and strategic partnership with Toyota to accelerate autonomous research.

The partnership with Toyota comes after a series of discussions with other carmakers, according to sources close to the matter. As with Google, many were reluctant to hand over their vehicles to Uber to be stripped of the company's branding. GM, on the other hand, chose to partner with Lyft instead in January 2016.

Uber was dissatisfied with its internal self-driving efforts, sources said, and that's one of the reasons why the company turned to after-market autonomous tech startup Cruise.

The two companies began discussions well after Cruise raised its $12.5 series A round but well before General Motors acquired the company for $1 billion in March, sources said. Sources close to Uber insist the two companies didn't discuss anything deeper than a technical partnership. Acquiring Cruise was never on the table.

But Cruise was looking for more than a technical partnership. The two mutually decided not to move forward with discussions.

For Cruise co-founder Kyle Vogt, Uber didn't provide the manufacturing capabilities required to mass-produce self-driving cars at the scale he wanted, sources said. Vogt also wasn't convinced that developing autonomous cars was Uber's priority, what with the company's battles in China and India.

It's no surprise that Uber would be aggressively seeking partners for its autonomous efforts. Industry experts expect the first iteration of a self-driving car-hailing network to hit the streets by 2019. Through its partnership with GM, Lyft is already well on its way to deploying at least the first iteration of its semi-autonomous cars. Self-driving taxi startup nuTonomy expects to deploy its first cars in Singapore in 2018 and at scale in 2019.

Uber has already been testing its autonomous software in Ford cars and recently expanded outside the comfort of its Carnegie Mellon test zones onto the streets of Pittsburgh. But until Toyota, the company had yet to find a partner that would help it mass produce the number of vehicles a fleet of on-demand self-driving cars would require.

Uber declined to comment for this story.