Crash Description
At 6:17 a.m. on March 1, 2019, a 2018 Tesla Model 3 passenger car was southbound in the right lane of the 14000 block of US Highway 441 (US 441), also known as State Road 7, in Delray Beach, Palm Beach County, Florida, when it struck a 2019 International truck-tractor in combination with a semitrailer. The combination vehicle (truck), operated by FirstFleet, Inc., was traveling east on a private driveway/access road for the Pero Family Farms agricultural facility (address: 14095 US 441) and was attempting to cross the southbound lanes of US 441 and turn left into the northbound lanes. As the truck approached the stop sign on the right side of the driveway at the intersection with US 441, it slowed but did not come to a full stop before beginning to cross the southbound lanes of the highway. The car driver, traveling at a recorded speed of 69 mph, did not apply the brakes or take any other evasive action to avoid the truck, which was crossing in front of him at about 11 mph.
The car hit the left side of the semitrailer just aft of the trailer’s midpoint. The roof of the car was sheared off as the vehicle underrode the semitrailer and continued south. Postcrash, the car coasted to a stop in the median between the southbound and northbound lanes, about 1,680 feet from where it struck the semitrailer (figure 1). The 50-year-old male car driver died as a result of the crash. The 45-year-old male truck driver was uninjured.
System performance data from the car showed that the driver was operating with the Tesla Autopilot technology package engaged at the time of the collision. Autopilot is a combination of advanced driver assistance systems (ADASs) that regulate vehicle speed and lane positioning through automated control of braking, steering, and throttle. The major subsystems associated with Autopilot operation are traffic-aware cruise control (TACC) and Autosteer. TACC is an adaptive cruise control system that provides longitudinal control (acceleration and deceleration). Autosteer is a lane-keeping assist system that provides lateral control (steering) of the vehicle within its lane. When Autopilot is activated, the ADAS is considered an SAE Level 2 system (partial automation). The performance of the Autopilot system is discussed later in this report.
NTSB Investigations
In its investigation of the fatal crash in Mountain View, California, the NTSB examined common issues regarding the safety of ADASs that provide partial automation. The final report incorporates lessons learned from the crashes in Williston and Delray Beach, Florida, in Culver City, California, and in Mountain View regarding the Tesla Autopilot system.
Discussion
In this crash, the truck driver reported seeing southbound traffic on US 441 but did not yield the right of way to the car, which was close enough to constitute an immediate hazard. In video from the security camera and from the Tesla’s forward-facing camera, the truck can be seen proceeding east on the intersecting private driveway and crossing US 441 in the car driver’s forward view. An attentive car driver would have seen the truck in time to take evasive action. At no time before the crash did the car driver brake or initiate an evasive steering action. In addition, no driver-applied steering wheel torque was detected for 7.7 seconds before impact, indicating driver disengagement, likely due to overreliance on the Autopilot system. The Autopilot system did not send a visual or audible warning to the driver to put his hands back on the steering wheel. The collision avoidance systems did not warn or initiate AEB due to the system’s design limitations. The environment was outside the ODD of the Autopilot system, and Tesla does not limit Autopilot operation to the conditions for which it is designed. Further, NHTSA does not have a method of verifying that manufacturers implement appropriate system safeguards for vehicles with Level 2 automation.
Probable Cause
The National Transportation Safety Board determines that the probable cause of the Delray Beach, Florida, crash was the truck driver’s failure to yield the right of way to the car, combined with the car driver’s inattention due to overreliance on automation, which resulted in his failure to react to the presence of the truck. Contributing to the crash was the operational design of Tesla’s partial automation system, which permitted disengagement by the driver, and the company’s failure to limit the use of the system to the conditions for which it was designed. Further contributing to the crash was the failure of the National Highway Traffic Safety Administration to develop a method of verifying manufacturers’ incorporation of acceptable system safeguards for vehicles with Level 2 automation capabilities that limit the use of automated vehicle control systems to the conditions for which they were designed.