Uber has ditched efforts to develop its own self-driving car with the multibillion-dollar sale of its driverless car division to a Silicon Valley startup. The ride-hailing company is selling the business, known as Advanced Technologies Group (ATG), for a reported $4bn (£3bn) to Aurora, a start-up that makes sensors and software for autonomous vehicles and is backed by Amazon and Sequoia Capital. As part of the deal, Uber is investing $400m in the venture, which employs 1,200 people, in return for a minority stake of 26%, and its chief executive Dara Khosrowshahi will join Aurora's board. The deal will also give Aurora access to a carmaker, Japan's Toyota, which has invested in ATG. Uber said it would collaborate with Aurora in bringing driverless cars to its network in the coming years.