During the fatal crash, the roof of the Tesla Model S was sheared off. Photo courtesy of NTSB.

During the fatal crash, the roof of the Tesla Model S was sheared off. Photo courtesy of NTSB.

The Tesla Model S driver killed in a Florida crash in May 2016, while the car was in Autopilot mode, was warned seven times by the car to place his hands back on the steering wheel during the 40 minutes preceding the collision, according to newly released reports from the National Transportation Safety Board.

Though the NTSB probe of the crash is still ongoing, the agency’s new reports shed additional light on a fatal crash that drew national headlines because the car was in Autopilot mode. This mode relies on advanced driver assistance systems, Traffic-Aware Cruise Control and Autosteer lane keeping, but falls well short of industry criteria for what’s considered a fully automated vehicle. Tesla instructs drivers to stay alert and continue to keep their hands on the steering wheel during Autopilot mode so they can readily take control when necessary.

The driver, 40-year-old Joshua Brown of Canton, Ohio, was traveling alone eastbound on US Highway 27A near Williston, Fla., when his Tesla Model S 70D struck and passed under a tractor-trailer truck making a left turn across two lanes. After impact, which sheared off the Tesla vehicle’s roof, the car left the road and continued through a drainage culvert and two wire fences before striking a utility pole, according to NTSB investigators.

Brown died in the crash, but the driver of the commercial truck wasn’t injured. 

NTSB investigators downloaded system performance data from the car’s vehicle recorder and from Tesla’s servers to reconstruct what led to the collision. The Model S was traveling 74 mph at the time of the crash, according to the reports. Brown had engaged Autopilot for 37 of the 41 minutes just before the collision. During those 37 minutes, Brown’s hands were detected on the steering wheel for a total of just 25 seconds.

Brown received a visual cue directing him to put his hands back on the steering wheel seven different times during the 40 minutes leading to the crash. Six of those visual cues also came with a chime warning, according to the reports. The last warning occurred about six minutes prior to the collision.

The NTSB reports just made public do not include analysis, conclusions or recommendations — those will come after the probe is completed.

An investigation by the National Highway Traffic Safety Administration, concluded Jan. 19 of this year, found that the crash wasn’t caused by any safety-related defect. Since the collision, Tesla has updated Autopilot’s steering wheel system for monitoring driver engagement. If a driver fails to respond to cues to keep gripping the steering wheel, the Autopilot mode will no longer be available for the remainder of the drive cycle.