The Uber test vehicle that struck and killed a pedestrian March 18 in Tempe, Ariz., was in computer-control mode at the time of the accident, the National Transportation Safety Board (NTSB) has determined. However, Uber told the agency that automated emergency braking wasn’t enabled.
“According to Uber, emergency braking maneuvers are not enabled while the vehicle is under computer control to reduce the potential for erratic vehicle behavior,” NTSB said in a news release announcing the preliminary results of its investigation. “The vehicle operator is relied on to intervene and take action. The system is not designed to alert the operator.”
The modified 2017 Volvo XC90, occupied by one vehicle operator and operating with a self-driving system in computer-control mode, struck a jaywalking pedestrian. The pedestrian died from her injuries; the vehicle operator was not injured.
At 1.3 seconds before hitting the pedestrian, the vehicle’s self-driving system determined that emergency braking was needed to mitigate a collision, according to NTSB.
The NTSB’s preliminary report states the pedestrian was dressed in dark clothing, did not look in the direction of the vehicle until just before impact, and crossed the road in a section not directly illuminated by lighting. The pedestrian was pushing a bicycle that did not have side reflectors and the front and rear reflectors, along with the forward headlamp, were perpendicular to the path of the oncoming vehicle.
The pedestrian entered the roadway from a brick median, where signs facing toward the roadway warn pedestrians to use a crosswalk, which is located 360 feet north of the Mill Avenue crash site, according to NTSB.
The report also notes the pedestrian’s post-accident toxicology test results were positive for methamphetamine and marijuana.
NTSB said Uber equipped the test vehicle with a developmental self-driving system, consisting of forward- and side-facing cameras, radars, lidar, navigation sensors and a computing and data storage unit integrated into the vehicle.
Volvo Cars equipped the vehicle with several advanced driver-assistance systems, including a collision-avoidance function with automatic emergency braking as well as functions for detecting driver alertness and road-sign information.
However, NTSB points out, the Volvo functions are disabled when the test vehicle is operated in computer-control mode.
Vehicle Noticed Pedestrian Six Seconds Before Impact
Data obtained from the self-driving system shows the system first registered radar and lidar observations of the pedestrian about six seconds before impact, when the vehicle was traveling at 43 mph, according to the NTSB report.
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.
Data from the self-driving system shows that the vehicle operator engaged the steering wheel less than a second before impact and began braking less than a second after impact, according to the NTSB report.
“The vehicle operator said in an NTSB interview that she had been monitoring the self-driving interface and that while her personal and business phones were in the vehicle, neither were in use until after the crash,” NTSB added.
All aspects of the self-driving system were operating normally at the time of the crash, and there were no faults or diagnostic messages.
NTSB said continues to gather information on the Uber self-driving system, the vehicle interface, the vehicle operator’s personal and business cellphones, the vehicle operator, the pedestrian and the roadway.
The preliminary report contains no analysis and does not discuss probable cause, the agency noted.