So I took a long 400 mile journey for work this week. It was an extremely frustrating drive. So many braking events.
In the 7300 miles I now have on my May 2021 M3, I think I've found the patterns of unintended/phantom braking using TACC. (no autopilot, I rarely use it)
- Cresting hills on 2-way roads. Happens occasionally with no other traffic, but happens ~80% of the time if another vehicle is oncoming on the other side of the hill either at the top or the bottom. As soon as the camera sees it, it brakes. This happens on very shallow rolling hills and also steep hills.
- Oncoming traffic on 2-way roads. Related to above, but even on perfectly flat sections, unintended braking occurs roughly 10% of the time regardless of conditions.
- Night time traffic on 2-way roads. I have only driven a significant distance a few times at night now. But in every case, I'd say 50% or more of oncoming vehicles triggered braking, didn't matter if hills, curves, or flat and straight. The only pattern I could find was older cars with dim headlights didn't trigger an event.
- Sunny conditions. I think I've figured why I get phantom braking when no one is within close range. Mirages. Yesterday I was following a car 1/2 mile ahead of me and kept getting a lot of phantom braking events when it was only me and him/her on the road. Occasionally I could see a reflection of the car in the mirage that looked much closer than it actually was. I wonder if this was fooling the cameras to see the car much closer that it was.
I haven't noticed a difference between when it's high noon or sun closer to the horizon. Seems to be the same result.
- The times I rarely get braking events are on one way roads, especially if TACC is actively following a car. (Although hills sometimes still trigger it.) Or when it's fully overcast/raining. Which leads me to believe mirages are tricking the system as described above, or perhaps the cameras are getting temporarily washed out from the sun, I'm not sure. Would be interesting to see a live view of the forward facing cameras.
I can confirm that completely blocking the front cameras locks out both autopilot and TACC. I thought maybe I could trick the car into defaulting to a dumb cruise system, but no dice. Just doesn't have that capability now.
I also get pillar "camera is blocked or temporarily blinded" alarms fairly often when they're not dirty or sun shining on that side. I wonder if I'm having camera failures... I've been thinking about calling the service center to have them take a look. And maybe they can also clear the 200 bug reports I recorded that I thought was being actively sent to Tesla's big brain center.