An Uber self-driving car that struck and killed a woman last year in Arizona failed to recognize her as a pedestrian because she was jaywalking, US transport regulators said Tuesday.

The Uber app open on a mobile telephone in London, Britain on November 10. Photo: VCG

The woman had been crossing the street "at a location without a crosswalk; the system design did not include a consideration for jaywalking pedestrians," the US National Transportation Safety Board (NTSB) said in a statement.

In a preliminary report, the NTSB had already determined that the car's software spotted the 49-year-old woman nearly six seconds before the vehicle hit her, as she walked across the street at night with her bicycle in Tempe, a suburb of Phoenix.

According to the latest report, which was issued ahead of a November 19 hearing to officially determine the accident's cause, the system at no time "classified her as a pedestrian" but rather, considered her an object. When the software determined that a collision was imminent approximately 1.2 seconds before impact, it suppressed any "extreme braking or steering actions" to reduce the potential for erratic vehicle behavior.

It did produce "an auditory alert to the vehicle operator as it initiated a plan for the vehicle slowdown." Uber resumed the driving testing in the US after suspending it for months.