The driver of a Tesla Model 3 involved in a fatal crash in Florida earlier this year engaged the vehicle’s Autopilot¹ system about 10 seconds before it collided with a truck – but did not have his hands on the steering wheel. That puzzling finding is part of the National Transportation Safety Board’s (NTSB) investigation into the incident. So is the fact that neither the driver of the Tesla nor the Autopilot system – otherwise known as an advanced driver assistance system (ADAS) executed evasive maneuvers, according to preliminary data and videos.

Here’s what the NTSB has determined so far:

• The ADAS, which provides both longitudinal and lateral control over vehicle motion—was active at the time of the crash.
• From less than 8 seconds before the crash to the time of impact, the vehicle did not detect the driver’s hands on the steering wheel.
• The Tesla was traveling about 68 mph when it struck the semitrailer.
• Neither the preliminary data nor the videos indicate that the driver or the ADAS executed evasive maneuvers.

The crash occurred on March 1 on State Highway 441 in Delray Beach, Florida. The Tesla struck a tractor-trailer that had pulled from a driveway, trying to cross its southbound lanes and turn left into the northbound lanes. According to surveillance video in the area and forward-facing video from the Tesla, the combination vehicle slowed as it crossed the southbound lanes, blocking the Tesla’s path.

The Tesla’s roof was sheared off when it struck the left side of the semitrailer and underrode the other vehicle. It finally came to rest on the highway’s median - about 1,600 feet from where it struck the semitrailer. The 50-year-old male Tesla driver died as a result of the crash. The 45-year-old male driver of the combination vehicle was uninjured.

The NTSB said it continues to gather information on the operation of the Tesla’s ADAS and the Tesla driver’s actions leading up to the crash. The investigation will also examine the driver of the combination vehicle, the motor carrier, highway factors, and survival factors. All aspects of the crash remain under investigation as the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar crashes. The NTSB is working in partnership with the Palm Beach County Sheriff’s Office during the investigation.

1.  Autopilot is a proprietary name used by Tesla for a combination of vehicle automation systems that provide driver assistance through the Traffic-Aware Cruise Control, Autosteer, and Auto Lane Change systems. According to Tesla, Autosteer uses camera sensors, radar, and ultrasonic sensors to determine how to steer the vehicle, and it requires drivers to hold the steering wheel—an alert is given to the driver if the system does not detect a driver hand on the steering wheel for a period of time.