NHTSA Complaint #11452681 — 2017 TESLA MODEL X

Firmware version: 2020.48.37.8 Date of Occurrence: 2/18/22 Location: I66 Westbound Description: On I66 Westbound near Rt123 Exit the car was traveling at 70mph and decreased 50mph. The car was on full autopilot. Set speed limit changed from 70 to 50mph but signage and the car's perceived speed limit was 55mph. No cars ahead of me to initiate the rapid deacceleration. The occurrence happened between 8 to 8:15AM. Weather was partly cloudy. Second occurrence of rapid deacceleration occurred on the same commute. On I66 Westbound near Rt50 the car was traveling at 70mph and the vehicle decreased speed to 30mph. The autopilot set to 70mph and rapidly deaccelerated to 30mph. Cars ahead were several car lengths away. No braking or deacceleration was observed by the cars ahead. The occurrence happened between 8:15 to 8:30AM. Weather was partly cloudy. Note, this issue has happened multiple times over the last 6 months. Didn't realize that this issue was reportable. Rapid deacceleration is fairly common event and has been observed on I66 (both directions), I95, RT28, RT29, I70, and I270.