A government report on the fatal collision between an Uber self-driving vehicle and a pedestrian in Tempe, Arizona, in March reveals that Uber's autonomous software system is not designed to brake automatically in case of emergencies.
Instead, the National Transportation Safety Board report said, and Uber confirmed, the vehicle operator is supposed to take over and hit the brakes. In addition, "the system is not designed to alert the operator," the report said.
The report is preliminary, and its investigation is ongoing "as the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar crashes," the agency stated.
In the crash in Arizona, an Uber self-driving vehicle undergoing testing fatally collided with a woman who stepped out in front of the moving vehicle, which was in autonomous mode and had a vehicle operator behind the wheel at the time of the crash.
According to the report, the sensors and cameras on the Uber vehicle detected the presence of a pedestrian on the side of the road "6 seconds before impact."
"As the vehicle and pedestrian paths converged, the self-driving system software classified the pedestrian as an unknown object, as a vehicle, and then as a bicycle with varying expectations of future travel path," it said.
Then, 1.3 seconds before the car collided with the driver, "the self-driving system determined that an emergency braking maneuver was needed to mitigate a collision." However, Uber's self-driving software "is not designed to alert the operator," who, according the report, took control of the steering wheel less than a second before the crash, and didn't begin braking until after the crash.
Uber uses Volvo vehicles to test its autonomous driving software. These vehicles come with a built-in driver assist system that does include "automatic emergency braking," according to the report. However, Uber disables this technology because it's not compatible with Uber's own autonomous system, which does not include automatic braking technology.
Uber said it can't comment on the details of the NTSB's report because the investigation is ongoing, but said it's cooperating with officials.
Video footage from interior cameras released by the Tempe Police Department in March shows that the vehicle operator was looking down, not at the road, in the seconds before the crash occurred. Regarding this, the report said that the operator told investigators "that she had been monitoring the self-driving system interface. The operator further stated that although her personal and business phones were in the vehicle, neither was in use until after the crash, when she called 911."
Uber shut down its on-road autonomous vehicle testing across the United States immediately after the crash and later that month, Arizona's governor suspended the company's ability to test its vehicles in the state. On Wednesday, Uber announced it was shutting down its operation in Tempe entirely, and laying off around 300 trained vehicle operators and other employees.
Uber will continue to develop self-driving technology in locations like Pittsburgh and San Francisco, cities where Uber engineering teams are located.
"We remain focused on our top-to-bottom safety review, having brought on former NTSB Chair Christopher Hart to advise us on our overall safety culture," the company wrote in an email statement.
The Tempe Police Department has also completed its investigation of the crash, but said in a statement Wednesday that the crash is "still considered an active investigation and as a result, we will not be releasing the report or details of the investigation."