An Uber self-driving Volvo SUV killed 49-year-old Elaine Herzberg as she walked her bicycle across a street during one of its test drives in Tempe, Ariz. The self-driven vehicle was headed down near Mill Avenue and Curry Road early Monday morning and is said to have struck the women, who was not in a crosswalk, as she crossed the street.

The Volvo SUV was a part of an Uber program aiming to develop commercial self-driving Ubers and is always accompanied by a person behind the wheel for safety measures.

The incident brought a turmoil of reactions from the social media, and lead to Uber pulling out its self-driving testing operations across American cities

The incident is the nation’s first fatal accident involving a self-driven vehicle. Despite the accident, self-driven cars have a track record for safe transportation. Famed billionaire and CEO of Tesla, Elon Musk, expects Tesla’s self-driving cars to be as much as 200 percent safer than a human driver by the end of next year.