A Tesla Model S that crashed into a fire department vehicle in South Jordan, Utah, while operating on Autopilot earlier this month accelerated for three to five seconds before the crash, according to data from the vehicle cited by the Associated Press on Thursday evening.
That is a new development amid the probe of the May 11 crash, in which the driver suffered a broken ankle. The National Highway Traffic Safety Administration is investigating.
According to the AP’s report, police suggested that the Tesla, which had been traveling at a pre-set speed of 60 mph, was behind another car that had slowed down to 55 mph before changing lanes. The Tesla slowed down as well, the report says, and when the leading car changed lanes, the Tesla accelerated to regain its pre-set speed shortly before impact.
The driver, who the AP identified as Heather Lommatzsch, said she owned the Model S for two years and had used Autopilot on various types of roads. Lommatzsch reportedly told police she believed the car’s automatic emergency braking system would have detected traffic up ahead stopped the vehicle before the crash.
South Jordan police said at the time of the incident: “Witnesses indicated the Tesla Model S did not brake prior to impact.”
Lommatzsch told police her Model S was traveling with Autopilot activated and that she had been looking at her phone. Tesla recommends that drivers keep their hands on the steering wheel while using Autopilot and to be prepared to take full control of the vehicle at all times.
Tesla’s semi-autonomous-driving technology emits multiple visual and audible warnings when it detects the driver’s hands are not on the steering wheel. The system will eventually deactivate itself if the driver ignores the warnings.
Vehicle data from the South Jordan crash indicated the driver’s hands were off the steering wheel for 80 seconds before the crash. It was not immediately clear whether Autopilot had deactivated itself at some point.
Tesla has frequently reminded drivers to stay in control of their vehicles when using Autopilot. The system cannot cause Teslas to drive themselves.