"The cars were having trouble driving through construction zones and next to tall vehicles, like big rigs".
Uber's self driving vehicles in Arizona have required human intervention on an average of every 13 miles (20.9 kilometres), which is significant when compared to the 5,600 miles (9,012 kilometres) between interventions required by Waymo's AVs in Californian trials.
Uber is known as one of the leading tech companies in the world. Khosrowshahi's trip was called "Milestone 1: Confidence" in the company documents.
In early March, he authorised self-driving vehicle companies to run tests without a person in the auto to act as a safety operator.
Uber and Waymo have a troubled past.
"We proactively suspended self-driving operations in all cities immediately following the tragic incident last week", an Uber spokesperson told AFP. It is not clear when the company will revive them.
Tempe Police Chief Sylvia Moir has told the San Francisco Chronicle that the SUV likely wouldn't be found at fault. NTSB is also reviewing the onboard self-driving system in Uber's test vehicle.
Experts who saw video of the Uber crash pointed to apparent failures in Uber's sensor system, which failed to stop or slow the auto as the victim, 49-year-old Elaine Herzberg, crossed a street pushing a bicycle. It shows that the car's backup driver was looking down just before the crash.
Authorities investigating the crash in a Phoenix suburb released the video of Uber's Volvo striking a woman as she walked from a darkened area onto a street.
Velodyne, the company responsible for manufacturing the Lidar sensors in Uber's autonomous cars said it was "baffled" by the incident and that it did not believe its hardware was to blame. We're heartbroken by what happened this week, and our cars remain grounded.
Uber said it would help investigators "in any way we can".
Ritukar Vijay, head of technology and strategy at autonomous vehicle startup Hi-Tech Robotic Systemz Ltd, analysed video footage of the accident and feels it could have been easily averted.
While the March 18 incident was the first pedestrian fatality involving a self-driving auto, it's not the first death involving an autonomous vehicle. While Uber temporarily suspended the automatic vehicles, the self-driving feature directly threatens innocent pedestrians, users of the app, and the driving jobs that provide income for about 16,000 Uber employees.