A Tesla Model 3 in a fatal crash with a semitrailer in Florida on March 1 was operating on the auto’s semi-autonomous Autopilot system, according to investigators with the National Transportation Safety Board (NTSB).

The car drove beneath the trailer, killing the driver. The crash was similar to one that happened in Florida in 2016 and that also involved use of Autopilot. In both cases, neither the driver nor the Autopilot system stopped for the trailers, and the roofs of the cars were sheared off. The Florida Highway Patrol and Tesla Motors are parties to the ongoing investigation, NTSB said.

Earlier this month, Tesla introduced two new safety features to help prevent drivers from inadvertently departing their lane. These new features are lane departure avoidance and emergency lane departure avoidance.

Tesla Model 3 accident

According to the NTSB preliminary report, on March 1 at about 6:17 a.m., a 2018 Tesla Model 3 electric-powered passenger vehicle was southbound in the right through lane of State Highway 441 (U.S. Highway 441) in Delray Beach, Florida, when it struck an eastbound 2019 International truck-tractor in combination with a semitrailer.

The Tesla Model 3 accident vehicle. Source: NTSBAs the Tesla approached a private driveway, the combination vehicle pulled from that driveway and traveled east across the southbound lanes of U.S. 441. The truck driver was trying to cross the highway’s southbound lanes and turn left into the northbound lanes. According to surveillance video and forward-facing video from the Tesla, the combination vehicle slowed as it crossed the southbound lanes, blocking the Tesla’s path.

The Tesla struck the left side of the semitrailer. The roof of the Tesla was sheared off as the vehicle passed beneath the semitrailer and continued south. The Tesla came to a rest on the median, about 1,600 ft from where it struck the semitrailer. The Tesla driver died as a result of the crash; the driver of the combination vehicle was uninjured.

Preliminary data from the vehicle show that the Tesla’s Autopilot system — an advanced driver assistance system (ADAS) that provides that automates vehicle maneuvers and acceleration — was active at the time of the crash. NTSB said that the driver engaged the Autopilot about 10 seconds before the collision. 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. Preliminary vehicle data shows that 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.

Tesla said in a statement that the driver did not use Autopilot at any other time during the drive before the crash. Vehicle logs show that he took his hands off the steering wheel immediately after activating Autopilot.

Tesla Model S accident

In the 2016 accident, a 2015 Tesla Model S, traveling eastbound on U.S. Highway 27A, west of Williston, Florida, struck and passed beneath a 2014 Freightliner Cascadia truck-tractor in combination with a 53 ft semitrailer. NTSB said that at the time of the collision, the combination vehicle was making a left turn from westbound U.S. 27A across the two eastbound travel lanes onto a local paved road.

The Tesla Model S accident vehicle. Source: NTSBAs a result of the initial impact, the battery disengaged from the electric motors powering the car. After exiting from underneath the semitrailer, the car coasted at a shallow angle off the right side of the roadway, traveled approximately 297 ft, and then collided with a utility pole. The car broke the pole and traveled an additional 50 ft, during which it rotated counterclockwise and came to rest perpendicular to the highway in the front yard of a private residence. The driver and sole occupant of the Tesla died as a result.

After that crash Tesla CEO Elon Musk said the company made changes to its system so radar would play more of a role in detecting objects.

The Tesla struck the right side of the semitrailer, approximately 23 ft forward from the end of the trailer. Damage from the collision was consistent with a 90° angle of impact. Minor damage above the height of the car was found on the semitrailer side panels, and the undercarriage of the trailer also showed only minor collision damage.

Tesla system performance data downloaded from the car indicated that vehicle speed just prior to impact was 74 mph. System performance data also revealed that the driver was operating the car using the ADAS features traffic-aware cruise control and autosteer lane-keeping assistance. The car was also equipped with automatic emergency braking designed to automatically apply the brakes to reduce the severity of or avoid frontal collisions.

As a result of the crash, the rear hatch frame separated and folded back over the crushed rear window. Other than the roof structure and the front bumper components that engaged the pole, the main body of the car was generally intact.

Using 3D laser-scanning technology, NTSB investigators documented the crash location, the damaged semitrailer and the damaged car. The Tesla was equipped with multiple electronic systems capable of recording and transmitting vehicle performance data. NTSB investigators said they will continue to collect and analyze data, and use it along with other information in evaluating the crash.