We Now Know Why the Self-Driving Uber That Killed a Pedestrian Didn't Brake

Uber's self-driving vehicles operating in Arizona were unprepared to safely encounter pedestrians and were fatally over-reliant on the mindfulness of human operators, a federal accident report released Thursday shows. On March 18, Uber's Volvo XC90 was being driven by software but supervised by a human attendant in the driver's seat when it hit and killed Elaine Herzberg, who was crossing the darkened road with her bicycle. It was the first fatal crash involving a vehicle driven by a computer, a technology that promises long-term safety improvements but has been rushed into road testing by a handful of companies despite questions about transparency and reliability. According to the preliminary report of the National Transportation Safety Board, Uber's sensors first perceived Herzberg about six seconds before impact--more than twice the commonly accepted reaction-time of 2.5 seconds. But the sensors struggled to classify Herzberg (first as an unknown object, then as a car, then as a bicycle) and determine her expected path across the road.