The Crashes That Shaped the Rules: Tempe, Williston, San Francisco

Joshua Brown's Tesla Model S, driving on Autopilot on a divided highway, passed under a tractor-trailer turning across its path; neither the system nor the driver braked. It was the first known fatal crash with a driver-assistance system engaged. NHTSA found no defect. The NTSB concluded that Autopilot had allowed prolonged inattention and had been used on a road it was not designed for, and recommended that makers limit such systems to their intended conditions and monitor drivers better, recommendations that took years and further crashes to be acted on.

Elaine Herzberg was walking a bicycle across a dark road when an Uber test vehicle, with a safety driver aboard, struck and killed her: the first pedestrian death involving an automated test vehicle. The NTSB found that the software had detected her nearly six seconds before impact but kept reclassifying her, that Uber had disabled the Volvo's own automatic braking, and that the safety driver had been looking at a phone. Uber stopped testing, settled with the family and eventually sold its self-driving unit; the safety driver was charged with negligent homicide and later pleaded guilty to endangerment. The industry's safety-driver protocols were rewritten around driver monitoring and two-person crews.

A pedestrian struck by a human-driven car was thrown into the path of a Cruise robotaxi, which hit her, stopped, and then pulled forward to the curb, dragging her about 20 feet. The car had followed its post-collision programming without knowing she was underneath. The crash itself was not the robotaxi's fault; the dragging was a failure of design, and Cruise's incomplete account of it to regulators became the larger scandal. The DMV suspended Cruise within the month; the company recalled its software, paid federal penalties, and was shut down by GM a year later.

Each crash moved a different lever. Williston made driver monitoring a design requirement that regulators eventually enforced. Tempe made safety-driver management a discipline and ended the era of one distracted employee in a test car. San Francisco made candour with regulators a survival condition and showed that a permit could be lost in a day. None of them stopped the technology; all of them changed how it is run.