Federal safety investigators say the autonomous Uber SUV that struck and killed an Arizona pedestrian in March spotted the woman about six seconds before hitting her, but didn't slow down because the vehicle's built-in emergency braking feature was disabled.
In a preliminary report on the crash, the National Transportation Safety Board said Thursday that emergency braking maneuvers are not enabled while Uber's cars are under computer control. That's a measure designed "to reduce the potential for erratic vehicle behavior," the NTSB said.
Instead, Uber's autonomous driving system "relies on an attentive operator to intervene if the system fails to perform appropriately during testing." The system is not designed to alert the driver.
In the crash, the driver of the Volvo XC-90 SUV began steering less than a second before impact but didn't brake until less than a second after impact, according to the preliminary report, which does not determine fault.
A video of the crash showed the driver looking down just before the vehicle struck and killed 49-year-old Elaine Herzberg in Tempe, Arizona.