The National Transportation Safety Board (NTSB) said it is still investigating the circumstances of a fatal Tesla crash last year to determine if the car or Tesla's Autopilot driverless system was at fault, but revealed more details about the circumstances of the crash.
The main finding the NTSB published is that the driver, a former US Navy Seal and Tesla enthusiasts, only had his hands on the steering wheel for less than 30 seconds during the 37 minutes when Autopilot was activated. The report also reveals the driver was prompted by an audible signal six times to place his hands on the steering wheel and warned seven times with a visual signal on the dashboard before the Tesla slammed into a truck that was crossing the divided highway.
Brown was suspected of watching a Harry Potter movie at the time of the crash, but the NTSB report also served to debunk the truck driver's witness account.
"Without the offset of the laptop clock to real time, it could not be concluded whether or not the driver was on the laptop at the time of the crash," the NTSB wrote. "No Harry Potter movie file was found on the hard drive of the device."
The NTSB report confirms earlier finding by Florida Highway Patrol.
Autopilot is by far the most advanced such system on the road, but it does not turn a Tesla into an autonomous vehicle and does not allow the driver to abdicate responsibility.
The report released by the NTSB — spanning hundreds of pages — details how Brown received numerous warnings from the car to put his hands on the wheel.
For the vast majority of the trip, the AUTOPILOT HANDS ON STATE remained at HANDS REQUIRED NOT DETECTED. Seven times during the course of the trip, the AUTOPILOT HANDS ON STATE transitioned to VISUAL WARNING. During six of these times, the AUTOPILOT HANDS ON STATE transitioned further to CHIME 1 before briefly transitioning to HANDS REQUIRED DETECTED for 1 to 3 seconds. During the course of the trip, approximately 37 minutes 16 passed during which the Autopilot system was actively controlling the automobile in both lane assist and adaptive cruise control. During this period, the AUTOPILOT HANDS ON STATE was in HANDS REQUIRED DETECTED for 25 seconds. For the remainder of this period, the AUTOPILOT HANDS ON STATE was in HANDS REQUIRED NOT DETECTED, or in one of the visual or aural warning states.
The report's findings are, of course, still inconclusive about whether Brown failed to properly heed warnings to take the wheel or not or whether Tesla's design or Autopilot was at fault. Regardless, once the NTSB ends its investigation, the debate about human fallibility versus the reliability of machine-driven cars will invariably continue.