(NEW YORK) — The National Highway Traffic Safety Administration has opened a special investigation into a fatal crash in California last month involving a Tesla that will look at the vehicle’s advanced driver assistance system, the agency confirmed to ABC News.

A 2014 Tesla Model S crashed into a parked firetruck on Interstate 680 near Walnut Creek shortly before 4 a.m. local time on Feb. 18, authorities said.

The driver was pronounced dead at the scene and a passenger was extricated from the vehicle with major injuries, according to the Contra Costa County Fire Protection District. Four firefighters were also transported to the hospital for evaluation, authorities said.

The fire truck had responded to the scene of an earlier crash that morning and was blocking I-680 lanes when the Tesla plowed into the rear of the fire engine, according to California Highway Patrol.

“It was unable to be determined at the scene if the Tesla was being operated with any driver assistance or automation activated at the time of the crash,” California Highway Patrol said in a statement at the time.

It was also unclear if drug or alcohol were a factor, police said.

The incident is NHTSA’s first special crash investigation this year, according to a case list obtained by ABC News.

ABC News was unable to reach Tesla for comment.

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