Overhead view of Hammock Dunes Place showing events in crash trip and tire evidence.

​​Overhead view of Hammock Dunes Place showing events in crash trip and tire evidence.

Electric Vehicle Run-off-Road Crash and Postcrash Fire

Investigation Details

What Happened

​​​This information is preliminary and will be supplemented or corrected during the course of the investigation.

An investigative update, dated October 21, 2021, is​ included below.

About 9:07 p.m. central daylight time on Saturd​ay April 17, 2021, a 2019 Tesla Model S P100D electric car, occupied by the 59-year-old owner and a 69-year-old passenger, was westbound on Hammock Dunes Place, a residential road in Spring, Harris County, Texas, when it crashed and caught fire.[1] Hammock Dunes Place is a concrete two-lane road with one westbound and one eastbound lane and mountable concrete curbs on either side. At the crash location, the roadway was level, with a curve to the south (figure 1). The roadway was equipped with streetlights but did not have lines to define the travel lanes. No speed limit sign​s were posted in the crash area, but the maximum speed limit for the road was 30 mph.

HWY21FH007-fig1.jfif  

​Figure 1. Hammock Dunes Place looking toward crash site.​

The crash trip originated at the owner's residence near the end of a cul-de-sac. Footage from the owner's home security camera shows the owner entering the car's driver's seat and the passenger entering the front passenger seat. The car leaves and travels about 550 feet before departing the road on a curve, driving over the curb, and hitting a drainage culvert, a raised manhole, and a tree.

The crash damaged the front of the car's high-voltage lithium-ion battery case, where a fire started. The fire destroyed the car, including the onboard storage device inside the infotainment console (figure 2). The car’s restraint control module, which can record data associated with vehicle speed, belt status, acceleration, and airbag deployment, was recovered but sustained fire damage. The restraint control module was taken to the NTSB recorder laboratory for evaluation.

HWY21FH007-fig2.jfif

Figure 2. Fire and impact damage to car.

The vehicle was equipped with Autopilot, Tesla’s advanced driver assistance system. Using Autopilot requires both the Traffic Aware Cruise Control and the Autosteer systems to be engaged.[2] NTSB tests of an exemplar car at the crash location showed that Traffic Aware Cruise Control could be engaged but that Autosteer was not available on that part of the road.

As a result of the crash and fire, both car occupants were fatally injured. The NTSB continues to collect data to analyze the crash dynamics, postmortem toxicology test results, seat belt use, occupant egress, and electric vehicle fires. The NTSB is working alongside the Harris County Texas Precinct 4 Constable'​​​s Office, which is conducting a separate, parallel investigation. The National Highway Traffic Safety Administration and Tesla are supporting the NTSB in the investigation.

Investigative Update, October 21, 2021

Investigative activities since the May 10, 2021 preliminary report was issued include a forensic examination to evaluate the deformation of the steering wheel. In addition, the NTSB Recorders Laboratory repaired the car’s event data recorder (EDR) and extracted critical precrash data from the unit.

​​Steering Wheel Examination

A postcrash inspection of the car showed that the steering wheel was damaged and deformed. The steering wheel was removed and transported to the NTSB Materials Laboratory for detailed examination. Initial results indicate that although some damage was caused by the intense heat of the postcrash fire, deformation along the top and left side of the steering wheel’s outer rim, as shown in figure 3, was due to an impact.

Steering wheel viewed from left.

Figure 3. Steering wheel viewed from left. Yellow dotted line shows measured displacement of outer rim from top right front corner of center hub cover.

Event Data Recorder

With the assistance of the EDR module manufacturer, the NTSB Recorders Laboratory repaired and downloaded the fire-damaged EDR. Data from the module indicate that both the driver and the passenger seats were occupied, and that the seat belts were buckled when the EDR recorded the crash. The data also indicate that the driver was applying the accelerator in the time leading up to the crash; application of the accelerator pedal was found to be as high as 98.8 percent. The highest speed recorded by the EDR in the 5 seconds leading up to the crash was 67 mph. [3]

As part of the investigative process, the NTSB is evaluating the EDR data and comparing it with the physical evidence documented from the crash scene and the vehicle. The data are also being compared with information developed by the NTSB Vehicle Performance Division in its analysis of security video showing the car at the beginning of the crash trip.

​The information in this update is preliminary and subject to change as the NTSB investigation progresses. Analysis of the crash facts, along with conclusions and a determination of probable cause, will come when the final report on the investigation is completed. No conclusions about how the crash happened should be drawn from the information in this investigative update. Additional information will be released as warranted. All aspects of the crash, including Tesla’s advanced driver assistance system, the postcrash fire, occupant egress, and results of the driver’s toxicological tests, remain under investigation while the NTSB determines the probable cause, with the intent of issuing safety recommendations to prevent similar events in the future.


  1. Spring is a census-designated place in the extraterritorial jurisdiction of Houston in Harris County, Texas.
  2. Traffic Aware Cruise Control 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) to keep a vehicle in its lane.​
  3. ​​​No speed limit signs were posted in the crash area, but according to Texas Transportation Code 545.352, the speed limit for the road is 30 mph.