A preliminary report conducted by the National Transportation Safety Board into the death of a 49 year-old woman, who was killed when she was struck by a self-driving Uber, has found that the autonomous vehicle detected an object six seconds before the crash.

Pedestrian Elaine Herzberg, 49, was killed instantly as she attempted to cross the road in Arizona. However, experts have now determined that Uber’s system detected Herzberg as an object six second before the crash, then as a vehicle and finally as a bicycle as the two converged.

At just 1.3 seconds before the collision, the self-driving system determined that emergency braking was needed. However, automatic emergency braking maneuvers are not enabled when the vehicle is in self-driving mode and the human operator is relied on to intervene and respond.

The NTSB highlighted a number of concerns that the global ride-hailing service will urgently have to address with its self-driving technology, one of which is that the system is not designed to alert the operator.

During interviews with the NTSB, the vehicle operator said she had been monitoring the self-driving interface prior to the impact. She engaged the steering wheel less than a second before impact and began braking less than a second after impact.

The NTSB seems to lay partial blame on the pedestrian as well. It was concluded that she didn’t look in the direction of the vehicle until just before impact, her bicycle didn’t have side reflectors and she crossed the road in a section without road lighting. Additionally, post-accident toxicology results were positive for methamphetamine and marijuana.