The back up driver of an Uber autonomous car that killed a pedestrian in Arizona, USA, in 2018, has been charged with negligent homicide, after lengthy investigations by the US National Transportation Safety Board (NTSB). Investigators found that the car's safety driver was streaming a television show episode at the precise time of the accident. The autonomous car's safety driver should have acted to prevent the accident. The accident is believed to be the first pedestrian casualty of self-driving technology. It has raised questions about whether Uber or the driver should be held responsible for the death. A state prosecutor's officer stated Uber would not face criminal liability for the accident. Investigators attributed the accident mostly to human mistake.