NHTSA Complaint #11449899 — 2021 TESLA MODEL Y

I have experienced many episodes of sudden, unexpected and seemingly inappropriate strong braking. The most common circumstance is overtaking semi truck/ trailers that are slowly ascending the mountain slopes of Interstate 5 in southern Oregon. Often the trucks have their emergency flashers in use. IT self-brakes from 65 mph down to perhaps 30-35 mph and I "take over" by depressing the accelerator. It also happens frequently with oncoming traffic on 2 lane highways night or day and usually on a curve. The problem is frequent enough to avoid using cruise control on 2 lane roads and on I-5 mountain grades. It happens reliably on my way to town where an intersection has a flashing light and the approach is downhill into a right hand turn. It does not happen travelling the other direction and does not require any other traffic. For all of these, the sudden braking puts myself and others at significant risk for a rear-ender" collision. There are no lights, warnings, or ability to learn what triggered the inappropriate braking. I do not have the full self-driving option on this vehicle. A call to Tesla for service concludes with, " There are no faults with any of the hardware in the vehicle and these behaviors are a limitation of software in the system at this time". I did not take it to them to look at the car as it is 5 hours of driving plus the service time to do so.