What we know is that the vehicle was on a divided highway with Autopilot engaged when a tractor trailer drove across the highway perpendicular to the Model S. Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied. The high ride height of the trailer combined with its positioning across the road and the extremely rare circumstances of the impact caused the Model S to pass under the trailer, with the bottom of the trailer impacting the windshield of the Model S.Still a lot of unknowns, but here is some thoughts
- Tesla uses cameras, not Lidars, as primary sensing. Cameras are known to issues with white object against bright sky and other scenarios. Elon Musk replied on his twitter that the radar ignored it to avoid false alarm for high object. This should have been discovered in the FMEA. What is the mitigation of Tesla during the FMEA? Did they test the driving in such scenarios? Is disabling autopilot in such scenario an option? With current Tesla sensing, whether it is possible to detect it with algorithm improvement?
- Testing. This accident provide a real case for other auto driving applications to test against, probably in simulation, also in controlled road. In simulation or in controlled environment, we can test the scenario leading to the accident, and add variations to the testing. The miles logged in testing is important but testing against known weakness is more important. As noted in the Tesla blog, "rare circumstances", but testable rare circumstances. We need to test such rare circumstances in simulations and controlled environment. We can discover such circumstances by FMEA, simulation, and logged near missed.
- Communication. Disappointed to see Tesla's blog post still emphasizing the fatality per mile is better than US average, and boasting that the safety features could have saved life had the situation been different. No. A life was lost. Let's focus on what we can improve first.