The National Transportation Safety Board report also says the SUV wasn't designed to slam on the brakes to reduce the severity of an unavoidable accident.
A 49-year-old woman was killed in the March 2018 crash while pushing a bicycle across a dark Tempe street.
It was the first fatality in the country involving a self-driving vehicle.
The Maricopa County Attorney's Office hasn't decided whether to file charges against the driver.
According to the Arizona Republic, the NTSB released more than 400 pages of documents this week ahead of a Nov. 19 meeting during which the board will discuss the probable cause of the crash.