DETROIT — A driver was behind the wheel when a Tesla electric car crashed and burned near Houston last April, killing two men, neither of whom were found in the driver’s seat.
The US National Transportation Safety Board released its findings in an update to its investigative report released Thursday into the April 17 crash on a residential road in Spring, Texas.
Although first responders found one man in the back seat and the other in the front passenger seat, the NTSB said both the driver and a passenger were in the front seats with their seat belts fastened at the time of the crash.
The agency said the car was traveling at 107 mph in the five seconds prior to the crash and the driver was accelerating. Data from the car’s fire-damaged data recorder revealed that the accelerator pedal was sometimes pressed down to 98.8%, the NTSB report said.
The investigation continues and the agency has not determined whether Tesla’s Autopilot partially automated driver assistance system was working at the time of the crash. The NTSB said it is still working on Autopilot, whether the men had any trouble getting out of the car, the driver’s toxicology tests and other items. The agency will make these findings in a final report.
The update report left unclear how or why the driver unfastened the seat belt and changed seating position, though it said the crash damaged the high-voltage lithium-ion battery case of the Tesla Model S, where the fire started.
The fatal journey began at the owner’s home at the end of a cul-de-sac, and home security video footage showed the owner sitting in the driver’s seat and the passenger in the front passenger seat, the report said. The car drove for about 150 meters before turning off the road, going over a curb, hitting a sewer, a raised manhole and a tree.
The accident happened around 9:07 p.m. on Hammock Dunes Place, a two-lane residential road. Both the 59-year-old owner and the 69-year-old passenger were killed.
In a preliminary May report, the NTSB said it was testing another Tesla vehicle on the same road and the Autopilot driver assistance system could not be fully utilized. Researchers were unable to get the system’s automated steering system to work, but were able to use Traffic Aware Cruise Control.
Autopilot needs both cruise control and automatic steering to function. Traffic Aware Cruise Control can keep the car a safe distance from vehicles in front, while autosteer keeps it in its own lane. The report said the road also had no lane lines. That could be the reason why the automatic steering would not work.
The agency says it plans to make safety recommendations to prevent similar accidents.
Local authorities said a man was found in the front passenger seat, while another was in the back.
Harris County Precinct Four Constable Mark Herman said the car was traveling at high speed at the time. He wouldn’t say whether there is evidence that someone has tampered with Tesla’s driver-monitoring system, which detects force from hands on the wheel. The system issues warnings and eventually shuts the car off if it detects no hands. But critics say Tesla’s system is easily fooled and can take a minute to shut down.
Consumer Reports said in April it could easily trick a Tesla into driving in Autopilot mode without someone at the wheel.
The NTSB, which has no regulatory authority and can only make recommendations, said it is working with the National Highway Traffic Safety Administration on the investigation. NHTSA has the authority to create vehicle safety regulations. The federal investigation is ongoing at the same time as a parallel investigation by local authorities, the NTSB said.
The Texas crash raised the question of whether Autopilot was working at the time and whether Tesla is doing enough to ensure drivers are involved. The company says in owner’s manuals and on its website that Autopilot is a driver assistance system and drivers should be ready to take action at any time.
Lars Moravy, Tesla’s vice president of vehicle engineering, said during the company’s conference call on April 26 that an inspection of the badly burned car found that the steering wheel was deformed, “so it raised a chance that someone could hit the driver’s seat. driver was seated at the time of the crash.” He said all seat belts were found loose.
Tesla CEO Elon Musk wrote on Twitter in April that the data logs “so far recovered” in the crashed show Autopilot had not been enabled and that “Full Self-Driving” had not been purchased for the vehicle in the Texas crash. He did not answer questions from journalists on Twitter.
NHTSA has stepped up its investigation into Tesla Autopilot. In August, it opened a formal investigation into the system after a series of collisions involving parked emergency vehicles.
The investigation covers 765,000 vehicles, nearly everything Tesla has sold in the US since the start of the 2014 model year. Of the crashes identified as part of the investigation, 17 people were injured and one was killed.
NHTSA says it has identified 12 crashes since 2018 in which Teslas on Autopilot or Traffic Aware Cruise Control have hit vehicles in scenes where first responders have used flashing lights, flares, an illuminated arrow board or hazard warning cones.