The system made two visual and one auditory alert for the driver to place his hands on the steering wheel, but those occurred more than 15 minutes prior to the crash, according to the report. Bystanders pulled Huang from the wreckage before the fire engulfed the vehicle, and he died later at a hospital.
A Tesla spokeswoman declined to comment on the NTSB's report and pointed to a March 30 company blog post.
Seven seconds before impact, the Tesla began "a left steering movement", meaning it veered to the left.
Tesla's owner's manual warns drivers that the system may not detect stationary objects when traveling at higher speeds.
The preliminary NTSB report released today does not assign blame for the crash, and officials say it may take a year or longer to determine the probable cause. In their report, the NTSB says Huang's Autopilot system sped up to 70.8 miles per hour (from 62 mph) three seconds prior to the crash, rather than slowing down or coming to a stop. Preliminary reports indicated the Model S she was traveling in may have sped up-similar to Huang's Model X-in the moments leading up to the crash.
The blog post states: "The driver had about five seconds and 150 meters of unobstructed view of the concrete divider with the crushed crash attenuator, but the vehicle logs show that no action was taken". While the report does not make a ruling on the primary cause of the crash, it does offer a breakdown of everything that happened in the lead-up to the collision, which claimed the life of Walter Huang.
The NTSB's preliminary report on the crash of a Tesla Model X on U.S. Highway 101 in the bay area suburb of Mountain View, Calif., indicates that Huang had the vehicle in it's semi-autonomous autopilot mode for almost 19 minutes before the crash. In January, a Tesla Model S that may have been on autopilot hit a parked firetruck on Interstate 405 near Los Angeles.
The Tesla collided with a so-called crash attenuator, a device covering the concrete barrier that's created to absorb a vehicle impact to lower risks of damage and injuries. The driver-assist feature was engaged for the last 18 minutes 55 seconds before the collision. At 4 seconds, the Tesla was no longer following a auto. "It is the driver's responsibility to drive safely and remain in control of the vehicle at all times", it says. The fire was extinguished in 10 minutes, but it reignited later that day in an impound lot.