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TACC bug in 2.4.236: confusing shadow for objects

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MarcG

Active Member
Oct 29, 2014
4,302
6,248
San Francisco
I've had the following happen twice so far since upgrading to 2.4.236 from 2.4.188:

Cruising along the highway in bright, sunny conditions at around 60 mph with TACC enabled and no cars in my lane (in front of me) for at least a mile, TACC suddenly starts braking hard upon approaching a dark shadow on the ground that covered at least the width of my lane and 25-30 feet long.

In one instance, I was about to go under a bridge that was casting its shadow onto the entire width of the highway.
In another instance, I was traveling south in the mid-afternoon and about to pass a slow-moving truck, in the lane to the right of mine, that cast its shadow onto my lane.

So it seems as though TACC is mistaking those shadows for objects and is trying to avoid colliding with them by braking hard. I tried to submit this as a bug report but it kept refusing to record it, stating something about having difficulty understanding.

Has anyone else experienced this?
 
I've had the following happen twice so far since upgrading to 2.4.236 from 2.4.188:

Cruising along the highway in bright, sunny conditions at around 60 mph with TACC enabled and no cars in my lane (in front of me) for at least a mile, TACC suddenly starts braking hard upon approaching a dark shadow on the ground that covered at least the width of my lane and 25-30 feet long.

In one instance, I was about to go under a bridge that was casting its shadow onto the entire width of the highway.
In another instance, I was traveling south in the mid-afternoon and about to pass a slow-moving truck, in the lane to the right of mine, that cast its shadow onto my lane.

So it seems as though TACC is mistaking those shadows for objects and is trying to avoid colliding with them by braking hard. I tried to submit this as a bug report but it kept refusing to record it, stating something about having difficulty understanding.

Has anyone else experienced this?

I haven't experienced this but also have not driven much yet under .236.

As for the in-car bug reporting, I've read that your recording is very much time limited--perhaps to ten to fifteen seconds or something. Perhaps that was the issue. I expect you've done this by now, but if not, I'd certainly urge you to write something up and send it in to [email protected].

Oh, and personally, I wouldn't consider this a "bug." This seems like a bigger problem to me than that.
 
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I'm not sure what to make of it.

The manual has the boilerplate "Traffic-Aware Cruise Control may react to vehicles or objects that either do not exist or are not in the lane of travel, causing the Model S to slow down unnecessarily or inappropriately"

But, of course they have that. They've covered themselves from just about everything with the user manual.

It happened to the OP enough in what I presume would be the same situations he encountered with the previous version so it seems like they added something. Like having the Camera play a stronger role.

Did you get a forward warring collision warning?
 
As for the in-car bug reporting, I've read that your recording is very much time limited--perhaps to ten to fifteen seconds or something. Perhaps that was the issue. I expect you've done this by now, but if not, I'd certainly urge you to write something up and send it in to [email protected].

Thanks for the info, I will try your suggestions.


It happened to the OP enough in what I presume would be the same situations he encountered with the previous version so it seems like they added something. Like having the Camera play a stronger role.

Did you get a forward warring collision warning?

Yep, I drive under the same bridge and in sunny weather at least twice a week. The truck shadow one is definitely new for me.

No forward collision warning, as it probably thought it had enough time to slow down before reaching it. By that time I had obviously overridden TACC by pressing on the accelerator..

Although, now that I think about it, I wonder if forward collision is only detected by the radar?
 
Yep, I drive under the same bridge and in sunny weather at least twice a week. The truck shadow one is definitely new for me.

No forward collision warning, as it probably thought it had enough time to slow down before reaching it. By that time I had obviously overridden TACC by pressing on the accelerator..

Although, now that I think about it, I wonder if forward collision is only detected by the radar?

According to the manual the forward collision warning uses the forward looking camera, and the radar.

What I find a bit scary is the Automatic Emergency braking also uses the Camera plus Radar combination as well. It does make sense because I'm not sure the radar by itself can detect a bicycle. I sure hope this system doesn't get tricked out by a shadow. Sure it only cuts speed by 25mph, but that can easily cause someone to rear end you.
 
FWIW:
Some days ago, driving with TACC on, 35 km/h (22 mph) on a quiet road with speed bumps, the car braked immediately after a speed bump, showing the blue car-in-front-being-tracked signal (although there was none).
Repeated 3 times. Fair weather, totally alone on the road.
Firmware 2.4.187 (or .188?).

Tried it the day after, could not be repeated (dont remember weather).

Installed 2.4.238 yesterday, will attempt repeat ASAP.
 
The same thing happened to me yesterday on 2.4.238 - the car suddenly braked hard, either for a shadow or for a vehicle parked on someone's lawn on the other side of the road.
I caught it on dash cam so have sent some footage to Tesla for them to have a look.
They acknowledged my email and my car suddenly started uploading at a rapid rate on my WiFi, so they've taken it seriously enough to take a closer look at my logs.
Hopefully it helps them find out what they need to fine-tune.

tesla-shadow-tacc.png


edited to add screengrab. What a glorious Winter's day
 
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Me too:
firmware 2.4.238 on a 15 days old 85D

Yesterday on a quiet, straight country road with trees along the sides.
Sun casts sharp shodows of trees on the road.
Driving 35-40-ish mph with TACC, no one else on the road, no parked cars or houses.
Car brakes all of a sudden. Not shure I saw/heard a collision warning; TACC shows blue car-in-front sign.

and:

Today, driving 30-ish on road with some trees, sun not sharp, but some shadows.
Minute bumps in road.
Alone on road, dont remember whether TACC was on.
Car suddenly raises a collision warning (sign, beep) and brakes.
 
Braking and/or just turning off due to overpasses and overhead signs is par for the course with the BMW i3 camera based ACC system. Many reports in the i3 forums. I'm pretty sure the BMW camera system is MobleEye too.
 
I have never had that happen when no cars are on the road. But I did have an incident that I reported to Tesla, where I was in slow and go and the BMW 3 Coupe started to slowly accelerate and my TACC hit the brakes very hard. Now after reading this, I think I was going under a bridge, a fairly small one at that.
 
The same thing happened to me yesterday on 2.4.238 - the car suddenly braked hard, either for a shadow or for a vehicle parked on someone's lawn on the other side of the road.
I caught it on dash cam so have sent some footage to Tesla for them to have a look.
They acknowledged my email and my car suddenly started uploading at a rapid rate on my WiFi, so they've taken it seriously enough to take a closer look at my logs.
Hopefully it helps them find out what they need to fine-tune.

View attachment 83286

edited to add screengrab. What a glorious Winter's day


I thought TACC is for highway use.

Cruise control on that street... ?

And the reasonableness test: to my eyes there is something wrong with that vehicle placement in view, so ya, I'd brake too.