Rafaela Vasquez, the safety driver of an Uber robotaxi prototype that hit and killed a pedestrian in Tempe, Arizona, in 2018 pleaded guilty last week to endangerment.

Her plea was accepted by the judge who sentenced her to three years of supervised probation, Fox 10 reported.

Prosecutors didn't file more serious criminal charges due to the National Transportation Safety Board (NTSB) determining that the main cause of the crash was Vasquez’s failure to monitor the road, according to Fox 10.

Vasquez was behind the wheel of a Volvo XC90 that Uber had equipped with its own self-driving system. The vehicle struck Elaine Herzberg who was crossing the road outside of a crosswalk while pushing a bicycle. Herzberg was taken to hospital and later died from her injuries.

The following police investigation determined that Vasquez had the series "The Voice" streaming on her phone for about 42 minutes and ending at 9:59 pm, which was a minute after the crash. A video also showed her looking down moments before the crash.

Vasquez's attorneys said their client was looking at a messaging system used by Uber employees on a work phone that was on her knee, while her personal phone, which was streaming "The Voice," was on the front passenger seat, Fox 10 reported.

A preliminary report by the NTSB indicated that Uber's lidar and radar spotted Herzberg 5.6 seconds before impact. At 1.3 seconds until impact, the system determined evasive action was required, and at one second before impact, Vasquez took control of the steering wheel. She did not apply the brakes until after the collision.

Uber said at the time that its self-driving system may have been calibrated in a way that the pedestrian was deemed a "false positive." Essentially, the system might have decided no action was required to avoid the incident.

Volvo wasn't implicated in any investigation because Uber had disabled the XC90's factory-installed automatic emergency braking software.

Uber later gave up its attempts to develop a self-driving system and in 2020 sold its division responsible for developing the technology, Uber Advanced Technology Group, to rival self-driving technology company Aurora. Uber will instead rely on self-driving systems from other companies for its future robotaxis. In 2022, Uber announced that a robotaxi from Hyundai-backed self-driving technology company Motional was being added to its fleet in Las Vegas.