When entering an interstate at rush hour, I was the first car in the line of those entering, and there were no cars ahead of me in the remaining length of lane. At the top of the ramp, with nothing in front of me, my car suddenly came to a complete stop with the screen flashing BREAK, telling me the automatic breaking engaged. The force of the break while driving 55 mph caused my body to fly forward (to the extent allowed by the seatbelt) and later a bruise across my chest. Everything loose in my car became a projectile. The car immediately behind me had to swerve to avoid hitting me, avoiding an accident. Problem is not reproducible as the system otherwise "works fine" and the car passes inspections. The car was under a year old at that point, and there were no other issues, warning lights, etc.