An Uber self-driving test vehicle that struck and killed a woman in 2018 had software problems, according to US security investigators.
Elaine Herzberg, 49, was struck by the car as she crossed a road in Tempe, Arizona.
The US National Transportation Safety Board (NSTB) found the car failed to identify her as a pedestrian.
The detailed findings raised a number of safety concerns, but did not determine the probable cause of the accident.
The Security Board is expected to make this finding when it meets on November 1
The findings, released on Tuesday, can also be used to form recommendations for the evolving autonomous driving industry. The sector has been under investigation in the wake of the accident.
The fatal crash happened in March 2018, involving a Volvo XC90 that Uber had used to test its self-driving technology.
Just before the crash, Herzberg had ridden a bicycle over a poorly lit stretch of a multi-lane road.
According to NSTB, Uber's test vehicle failed to correctly identify the bike as an impending collision until just before collision.
At that time, it was too late for the vehicle to avoid the crash.
"The system design did not include the consideration of pedestrian walking," said the NTSB.
The report also said that there were 37 crashes of Uber vehicles in self-driving mode between September 2016 and March 2018.
In a statement, Uber said: "We value the depth of NTSB's investigation into the crash and look forward to reviewing their recommendations . "
Earlier this year, prosecutors ruled that the company is not criminally responsible for Herzberg's death.
However, the car's rear driver could still face criminal charges.
Dash-cam footage released by police after the incident appeared to show the vehicle's back-up driver, Rafaela Vasquez, taking his eyes off the road moments before the accident.
Several records from the streaming service Hulu suggested that Vasquez had streamed a TV talent show on a phone at the time of the crash.
After the crash, Arizona authorities suspended Uber's ability to test self-driving cars on the state's public roads.
The company then pulled the plug on its autonomous car operation in Arizona, although the company later resumed testing in Pennsylvania