Thread by @greentheonly

Preface: This is an unscientific experiment on many-many levels. The trailer is not moving. The "road markings" make no sense.

The experiment is only on TACC, since AP typically won't engage anyway. 18mph is the minimum TACC speed.
Blue circle on the left in IC = TACC is ON. 1/

when you press brake pedal, TACC turns off (blue circle disappears). That's how you know intervention happened.

Please forgive me for not trying 50mph.

The results were somewhat inconsistent. From IC display a theory emerged truck was pingponging between detected lanes 2/

great thing about the videos below is they don't require anything special from you. just find a trailer, connect your dashcam/IC cam and you can try the same scenario I did (just be careful!)
I am planning to ask a model3 owner I know locally to try it as well soon. 3/

In only takes 9 seconds to reach the target even at 18 mph, imagine it was 50+? A lot less time for AP to flip-flop with brakes I guess?

Confession, I chickened out and could probably have braked somewhat later and still end up ok.

#Tesla 4/

here a lot more cautionous. has some chances to engage full AP, but obviously was not watching IC. 5/

Approaching from the other side. We can declare this one as an almost clear autopilot pass. 6/

Love the dancing truck at the start of footage on IC. I guess this is another pass.
While it looks this side is working, I had some fails too, just have no IC + dashcam for it. only augmented. 7/

at least it slowed down some more this time. 8/

Now you might ask what's the autopilot seeing? There's a bit of a problem in that Tesla changed some internal representations and we did not catch up 100% yet. In the video below ignore the speeds, just look at the blue circle as the indicator TACC is on or not. 9/

So looking at it - seems the IC theory is totally confirmed. I need to try to ster "in lane" and see what happens. (same order as above for these videos.

(Firmware version 19.16.2)

10/

reminder - speed display is inorrect, just look at the blue circle. 11/

reminder - speed display is inorrect, just look at the blue circle 12/

reminder - speed display is inorrect, just look at the blue circle 13/

reminder - speed display is inorrect, just look at the blue circle 14/

reminder - speed display is inorrect, just look at the blue circle 15/

reminder - speed display is inorrect, just look at the blue circle.
selection of approach does play a role as you can see. 16/

So, what's the conclusion, you may ask? Well, I think it's pretty clear: don't drive on autopilot/TACC in parking lots!

Esp. don't drive on autopilot in parking lots at speeds above 55 MPH.
17/

On a serious note: if it took 15-18mph approach 10 seconds to reach that truck from that distance, does that mean 60mph would happen in less than 3? that's a whole lot less time to react (for both driver and AP). Esp. if the semi is actually moving. 18/

Basically AP, or no AP, if you look away for a second or close your eyes (or sneeze, many don't realize we close our eyes when sneezing, or perhaps even yawn) while driving at 60+MPH in a fast changing environment - you can easily die. Speed is underestimated factor by many.
FIN/

Follow up from a fearless model3 owner.

View with IC.

He reported you need to aim into the opening as aiming for the cables makes the AP stop (consistent with my experience) which further shows that vision does play quite a big role.

In this footage car reportedly stopped 2 ft of hood under the trailer.