Tesla Model X on Autopilot hits highway barrier in Mountain View

What happened

At 9:27 a.m. on March 23, 2018, a 2017 Tesla Model X P100D was traveling south on US Highway 101 in Mountain View, California, in the second lane from the left, a high-occupancy-vehicle lane. As it approached the paved gore area that separates the main lanes from the left-exit ramp to State Route 85, the SUV moved left into the gore.

The NTSB found that the vehicle struck a crash attenuator at the end of a concrete median barrier at about 71 mph. The attenuator had been damaged in an earlier crash and was not operational. The SUV rotated, its front structure separated from the rear, and it was then struck by a Mazda 3 and an Audi A4. The Tesla’s high-voltage battery was breached and a post-crash fire began.

Bystanders pulled the 38-year-old driver from the vehicle before it was engulfed in flames. He died at a hospital. The Mazda driver had minor injuries and the Audi driver was not hurt.

The system involved

The vehicle was a privately owned 2017 Tesla Model X P100D. System data showed the driver was using Traffic-Aware Cruise Control and Autosteer, the features Tesla calls Autopilot. Autopilot is a partial driving automation system that requires continuous driver supervision; at the time, Tesla monitored engagement through sensing of the driver’s hands on the steering wheel.

Investigation and response

The NTSB investigated the crash (HWY18FH011). It determined the probable cause was the Autopilot system steering the SUV into the gore area because of system limitations, together with the driver’s lack of response due to distraction, likely from a cell phone game application, and overreliance on Autopilot. Contributing factors were the Tesla’s ineffective monitoring of driver engagement and the damaged, nonoperational attenuator, which the board attributed to the California Highway Patrol’s failure to report an earlier crash and to systemic problems in the California Department of Transportation’s maintenance of safety hardware.

The board issued recommendations to NHTSA, OSHA, SAE International, Apple and other makers of portable electronic devices. Consumer Reports reported that at the February 2020 board meeting the NTSB criticized Tesla for not responding to an earlier recommendation on driver monitoring and criticized NHTSA’s oversight approach; NHTSA responded that it would review the recommendations.

Separately and later, NHTSA’s Autopilot investigations PE21-020 and EA22-002 led Tesla to file recall 23V-838 on December 12, 2023, covering 2,031,220 vehicles. Tesla’s recall report said the prominence and scope of Autosteer’s controls may not be sufficient to prevent driver misuse, and that Tesla did not concur with the agency’s analysis but agreed to an over-the-air update adding controls and alerts. NHTSA closed EA22-002 on April 25, 2024, and opened a recall query to assess the remedy.

What is not established

The NTSB did not conclusively establish that the driver was holding his phone at the moment of the crash, according to Consumer Reports. The December 2023 recall was not a direct response to this crash; it is included as context for later regulatory action on the same system.