NHTSA Complaint #11560404 — 2020 TESLA MODEL 3

During a month-long road trip in the US, I experienced frequent "phantom braking" incidents while using adaptive cruise control. In some cases, Autosteer was also active. By "phantom braking" I refer to sudden hard braking by the car itself in clear daylight conditions on interstate highways with no vehicles visible ahead of me for at least 1/2 mile. By "frequent" I mean that this behavior occurred multiple times per hour over multiple days. I decided to cease using cruise control for the remainder of the trip after the following episode occurred. With cruise control active on a four lane interstate, I was changing lanes to the right to allow a pickup truck to pass me on the left. I had just passed a semitrailer, who was in the right lane. I could see him in my rear-view mirror as I began the lane change. The road was empty and visible for at least a mile ahead on a sunny morning. We were all traveling about 75 mph in a 70 mph zone. While straddling the lanes, the car suddenly slammed on its brakes, requiring both vehicles behind me to take evasive action. I over-rode the car’s action by pressing the accelerator pedal swiftly and firmly. No accident occurred. I stopped using cruise control entirely for several months, and I have only rarely used it since then, and only when the road behind me is empty. In those few recent trials, I have not experienced any phantom braking. Finally, I speculate that the braking may have been triggered by "mirages" of what look like puddles on the road. We humans are familiar with this phenomenon, but the camera AI may have interpreted those as obstacles.