In this Contra Costa County Fire Protection District photo, firefighters are seen at the scene of a fatal crash involving a Tesla and a Contra Costa County fire truck on Feb. 18, 2023, in Contra Costa, California.

Contra Costa County Fire Protection District

Federal vehicle safety regulators launched a new, special crash investigation into a fatal crash involving a Tesla Model S sedan and a fire truck in Walnut Creek, Calif., last month, CNBC has confirmed.

The driver of the Tesla died, a passenger was seriously injured and four firefighters who were in the fire truck were taken to a hospital after the crash, according to CNBC reports from the California Highway Patrol and the Contra Costa County Fire Department.

The Associated Press first reported about the special investigation by the Norwegian Road Safety Agency.

According to fire department records after the Feb. 18 incident, the fire truck was parked in the middle of a freeway to protect other emergency personnel who were towing a disabled vehicle from the area when the Tesla vehicle swerved into it.

NHTSA and the CHP have opened separate investigations into the crash.

The CHP wrote in a statement after the fatal incident, “It is unclear if drug or alcohol impairment is a factor in this crash. It could not be determined at the scene if the Tesla was being operated with any driver assistance or automation activated at the time of the crash.”

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Both the CHP and NHTSA want to know whether Tesla’s driver assistance systems, marketed as Autopilot and Full Self-Driving options in the US, caused the crash.

All new Tesla vehicles in the US come with a standard driver assistance package called Autopilot. Customers who pay Tesla a monthly subscription fee of $199 or $15,000 up front can also get additional driver assistance features as part of a premium package called FSD, which stands for Full Self-Driving. Tesla also allows FSD customers to sign up for FSD Beta, which is a way to test new features that haven’t been fully debugged on public roads.

Despite their branding, Tesla is not making a driverless vehicle or system. The company warns drivers to keep their hands on the wheel and be ready to take over steering or braking at any moment.

The crash investigation is part of a wide-ranging NHTSA investigation into Tesla’s driver assistance systems and how they work around parked first responder vehicles.

According to information on the agency’s website, NHTSA opened a “preliminary evaluation” of Tesla’s Autopilot system on August 13, 2021. “The opening of the investigation was prompted by an accumulation of crashes in which Tesla vehicles, operating with Autopilot engaged, hit stationary vehicles on the road or roadside tending to pre-existing crash sites,” the report said.

According to the NHTSA report, at least 14 Teslas have crashed into first responder vehicles while using the autopilot system.

NHTSA expanded the probe to an “engineering analysis” in the spring of 2022, to determine whether Tesla’s systems could “exacerbate human factors or behavioral safety risks by undermining the effectiveness of driver monitoring.”

In layman’s terms, NHTSA is trying to determine whether Tesla’s Autopilot, FSD, and other driver assistance features are causing drivers to be so distracted from the road that they would drive safer without them.

Tesla did not respond to a request for comment. NHTSA does not comment on open investigations.