Developers of self-driving cars, such as Tesla and Waymo, are making the technology more common for riders in a few US cities, Dara Khosrowshahi said on the company's fourth-quarter earnings call.

Uber CEO Dara Khosrowshahi has said his firm is open to cooperating with Elon Musk's Tesla in the driverless car market. At the same time, Khosrowshahi took a slightly more combative tone with Amazon.

Uber CEO Dara Khosrowshahi said Wednesday that making self-driving cars widespread on the app will take time.Eric Risberg / AP Uber CEO Dara Khosrowshahi said making driverless cars common in ride ...