In a statement, Tesla Motors said this is the "first known fatality in just over 130 million miles [210 million km] where Autopilot was activated" and suggested that this ratio makes the Autopilot safer than an average vehicle. The radar should not have had any problems detecting the trailer, but according to Musk, "radar tunes out what looks like an overhead road sign to avoid false braking events." Almost every other self-driving car with a goal of sophisticated autonomy uses LIDAR to fill this kind of sensor gap, since LIDAR provides high resolution data out to a distance of several hundred meters which much higher resiliency to ambient lighting effects. This bypasses almost all front-impact safety systems on the passenger vehicle, and as Tesla points out, "had the Model S impacted the front or rear of the trailer, even at high speed, its advanced crash safety system would likely have prevented serious injury as it has in numerous other similar incidents."
Is "reasonably safe" defined by the average human driver, the perfect human driver, or the perfect computer driver? Because of the risk of such a lawsuit, the potential legal costs faced by manufacturers of autonomous vehicles are higher than the costs faced by human drivers. Most auto accidents usually result in pretrial settlements, and the 4 percent of cases that go to trial have relatively low legal costs and low potential damages, compared with those of a design-defect lawsuit. As the safety of autonomous vehicles improves and as legal costs become more predictable, stricter safety standards could be imposed to encourage further progress.