WASHINGTON: An Uber self-driving car detected a pedestrian six seconds ahead of a fatal Arizona crash that killed the woman but failed to activate emergency braking, a preliminary investigation report said Thursday.
The National Transportation Safety Board said its preliminary report stopped short of assigning blame for the March fatal accident in Tempe, Arizona, adding that any conclusion would come in its updated report.
But the NTSB said Uber's engineers had disabled an automatic emergency braking system "to reduce the potential for erratic vehicle behavior."
The report said the self-driving system determined that emergency braking was needed 1.3 seconds before impact but that by then it was too late.
The person in the driver's seat for emergencies applied the brakes less than a second before impact, unable to avoid the woman.
The NTSB said preliminary reports by their nature do not determine the probable cause of an accident, and that "all aspects of the crash remain under investigation."
- Methamphetamine, marijuana -
The report said the pedestrian was dressed in dark clothing and was pushing a bicycle that had no side reflectors when she crossed a section of roadway which had no lighting.
Toxicology tests results for the pedestrian "were positive for methamphetamine and marijuana," the report added.
Uber said in a statement it was cooperating with the safety investigation.
"Over the course of the last two months, we've worked closely with the NTSB," an Uber spokesperson said.
"As their investigation continues, we've initiated our own safety review of our self-driving vehicles program. We've also brought on former NTSB Chair Christopher Hart to advise us on our overall safety culture.
Uber suspended its autonomous driving testing in several locations in the United States after the accident.
The ridesharing giant said it hopes to resume testing in California and elsewhere, but indicated this week it would not restart in Arizona.
After the accident, Arizona governor Doug Ducey sent Uber chief executive Dara Khosrowshahi a letter saying he has directed transportation department officials to suspend Uber's testing in the state and said he found the video of the crash "disturbing and alarming."
Thursday's NTSB report said the Uber car's LIDAR (Light Detection and Ranging) detected the pedestrian "about six seconds before impact, when the vehicle was traveling 43 mph," or 69 kilometers per hour and that the car's 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 Uber's system "is not designed to alert the operator," who is expected "to intervene and take action" in an emergency.