The Tesla Model S accident that last year sparked a debate about the car company’s partially autonomous driving tools resulted in a cloud of white dust as the sedan plowed underneath a tractor trailer, a witness told investigators.
“Just a white cloud, like just a big white explosion,” said Terrence Mulligan, a witness who saw the impact and rushed to where the electric vehicle came to rest, told investigators with the U.S. National Transportation Safety Board.
The NTSB on Monday released hundreds of pages of technical reports on the May 7, 2016, accident. It hasn’t yet concluded what caused the crash. The reports offered new details of the violent accident, but stopped short of clarifying why the driver didn’t attempt to override the car’s autonomous systems.
A Tesla spokeswoman referred inquiries to previous company statements about the crash. The company in June 2016 said its autopilot was engaged at the time of the crash and the company informed NHTSA about the accident immediately.
“Autopilot is by far the most advanced driver-assistance system on the road, but it does not turn a Tesla into an autonomous vehicle and does not allow the driver to abdicate responsibility,” the company said.
The U.S. National Highway Traffic Safety Administration earlier this year found that the owner of the Tesla Model S sedan had ignored the manufacturer’s warnings to maintain control even while using the driver-assist function. The agency said it found no defect in the vehicle and wouldn’t issue a recall.
The NTSB probes only a handful of highway accidents each year in search of broad safety lessons. Unlike NHTSA, it can only issue recommendations.
The Tesla broadsided the truck, which was crossing the highway near Williston, Florida. The impact killed the Tesla driver, Joshua Brown, who had set the car to a speed of 74 miles an hour in a zone limited to 65 miles per hour.
There was no application of the brakes by either the driver or Tesla’s automatic braking system before the impact, according to an analysis of the car’s on board electronic data.
The Tesla, its roof sheared off and crumpled at the rear of the car, continued down the road until it struck a utility pole and came to rest in a home’s driveway.
A review of his mobile phone and other electronic devices found in the car didn’t uncover any evidence that they were in use at the time of the crash. Some initial news reports had suggested Brown had been watching a movie while driving.
Brown, 40 and a former Navy SEAL, had been cited for speeding eight times between 2010 and 2015, according to Ohio records cited by the NTSB. He also had received a ticket for failing to obey a traffic signal, NTSB said.
The driver of the truck had had his license suspended five times between 1984 and 2013 for violations including speeding and failure to appear in court, according to NTSB.
While the truck driver wasn’t using his phone at the time of the crash, he had made multiple calls and sent texts while working earlier in the day, according to the reports. He declined to speak with NTSB investigators, though his lawyer provided them with some records.
The safety board’s next step is to issue a report on the cause of the accident and any recommendations for preventing a re-occurrence.