Uber says is explicitly down to programming issues, rather than human error. The developmental cars are still manned by a human driver at all times. The company added that one video, where a car ran a red light, happened while the vehicle was being operated by the driver. Uber is also running the cars in San Francisco without a permit, because its cars won't operate without a human operator seated at the wheel.

Weidenmeter says he brought the issue to the engineering team after his preview ride, but it wasn't fixed before the ride-sharing service expanded its self-driving car roll-out two days later. The cars' human "safety drivers" were told to take manual control when turning right in a street with a bike lane, while engineers continued to work on the programming flaw.