The Tesla Model X that slammed into a freeway barrier in California in March was operating on Tesla's Autopilot system and sped up from 62 mph to about 71 mph in the moments before the fatal crash, according to a report by the federal National Transportation Safety Board. The vehicle did not brake or attempt evasive steering, and the driver's hands were not detected on the steering wheel in the seconds before impact, according to the report.
The preliminary report details what has been uncovered about the March 23 incident that killed Walter Huang, a 38-year old Apple engineer, but does not make final conclusions about the cause as the NTSB investigation continues.
The car crashed into an energy-absorbing system, called an "attenuator," on a concrete barrier where two freeways divide in Mountain View, Calif. The Model X driver was using the Tesla Autopilot system that includes adaptive cruise control and lane-keeping steering assist. The report details these events leading up to the crash based on data from the car:
- Autopilot was engaged for the last 18 minutes, 55 seconds, and in that time the vehicle gave the driver two visual alerts and one auditory alert to put his hands on the steering wheel; all were more than 15 minutes prior to the crash.
- In the minute before the crash, the driver's hands were detected on the wheel three times for a total of 34 seconds - but the system detected no hands on the wheel in the last 6 seconds before impact.
- At 8 seconds before the crash, the Model X had adaptive cruise control set at 75 mph but was following a slower lead vehicle at about 65 mph. At 7 seconds, the Tesla began steering left following that vehicle.
- At 4 seconds, the Model X no longer was following that lead vehicle.
- At 3 seconds before hitting the barrier, the Tesla accelerated from 62 mph to 70.8 mph, and no braking or evasive steering movement was detected.
Two other vehicles became involved in the crash, and the Tesla's battery also caught fire. The NTSB is investigating the fire, as well as the battery reigniting five days later while the vehicle was in an impound lot.
Tesla has not commented on the report, but emphasized in a March 30 blog post the safety potential of its Autopilot system and noted that the Model X "had about 5 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."
In addition to the NTSB probe, the National Highway Traffic Safety Administration is investigating a May crash in Utah in which a Tesla Model S crashed into a fire truck stopped at a traffic light. Police said that vehicle had Autopilot engaged and that the driver admitted that she was looking at her phone before the crash, in which she suffered minor injuries.
The NTSB in September issued a final report on a fatal crash of a Model S on Autopilot, in which the car crashed into a truck crossing the highway. The report cited driver error on the part of the truck driver as well as on the Tesla driver for inattention. But it also concluded that the "operational design" of Autopilot allowed the driver to rely too heavily on the features and to be inattentive.
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