The National Transportation Safety
Board issued Thursday its preliminary report for the investigation of the fatal,
March 23, 2018, crash of a Tesla on U.S. Highway 101 in Mountain View,
Information contained in the report is preliminary and subject to change during the NTSB’s ongoing investigation.
Preliminary reports, by their nature, do not contain analysis and do not
discuss probable cause and as such, no conclusions about the cause of the crash
should be drawn from the preliminary report.
According to performance data downloaded from the
crash vehicle, a 2017 Tesla Model X P100D, the driver was using traffic-aware
cruise control and autosteer lane-keeping assistance, which are advanced driver
assistance features that Tesla refers to as autopilot. The vehicle was
approaching the state Highway 85 interchange, traveling south on U.S. Highway
101, in the second lane from the left — a high-occupancy-vehicle lane.
As the vehicle approached the paved gore area dividing
the main travel lane of U.S. Highway 101 from the state Highway 85 exit ramp,
it moved to the left and entered the gore area at approximately 71 mph,
striking a previously damaged, SCI smart cushion crash attenuator system. The
speed limit for the roadway is 65 mph. The vehicle’s traffic-aware cruise
control was set to 75 mph at the time of the crash. The Tesla was subsequently
involved in collisions with a 2010 Mazda 3 and a 2017 Audi A4. The Tesla’s
400-volt, lithium-ion, high-voltage battery was breached during the crash and a
post-crash fire ensued. The Tesla’s driver was found belted in his seat and
bystanders removed him from the vehicle before it was engulfed in flames. The
Tesla driver suffered fatal injuries while the driver of the Mazda suffered
minor injuries and the driver of the Audi was not injured.
(Southbound view of U.S. Highway 101 depicting the Tesla, Audi and Mazda
vehicles at their final rest locations following the crash. The location of the
SCI smart cushion crash attenuator system is also identified. Photo courtesy of
A preliminary review of the Tesla’s recorded performance data showed:
- The Autopilot system was engaged on
four separate occasions during the 32-minute trip, including continuous
operation for the last 18 minutes and 55 seconds prior to the crash.
- In the 18 minutes and 55 seconds
prior to impact, the Tesla provided two visual alerts and one auditory alert
for the driver to place his hands on the steering wheel. The alerts were made
more than 15 minutes before the crash.
- The driver’s hands were detected on
the steering wheel for a total of 34 seconds, on three separate occasions, in
the 60 seconds before impact. The vehicle did not detect the driver’s hands on
the steering wheel in the six seconds before the crash.
- The Tesla was following a lead
vehicle and traveling about 65 mph, eight seconds before the crash.
- While following a lead vehicle the
Tesla began a left steering movement, seven seconds before the crash.
- The Tesla was no longer following a
lead vehicle four seconds before the crash.
- The Tesla’s speed increased —
starting three seconds before impact and continuing until the crash — from 62
to 70.8 mph. There was no braking or evasive steering detected prior to
The Mountain View Fire Department applied about 200 gallons of water and foam
to extinguish the post-crash fire. The battery reignited five days after the
crash in an impound lot and was extinguished by the San Mateo Fire Department.
The preliminary report is available online at https://goo.gl/cDv2kf.
The NTSB’s investigation of the crash is ongoing. Major investigations and
investigations of crashes involving fatalities are generally completed in 12 to