TACC failed to brake at stop, nearly accident.

[Racerx22b]

well, to be clear, I would say it's not really the TACC system that failed, but rather the "automatic emergency braking" system that failed.

whatever you want to call it, it's brand new in 6.2, and it failed to stop. that's pretty damn clear to me that it's a massive failure of the reliability of the system, especially when they go around touting the feature in the release notes.

View attachment 77886

actually, before I even say any more about this feature failing, OP - are you on 6.2 or are you on 6.1?

@Lintrix - First of all, why in the hell are you using TACC on a clearly congested surface street? If you do make the poor decision to use this you NEED to maintain control of the vehicle. There are too many variables that I don't think any computer algorithm can account form.

@yobigd20 - Secondly, AEB did not fail. What part of the release notes that say "reduce the impact of an unavoidable frontal collision" are you not understanding? Even if you would've rear ended the car you swerved to miss AEB would've reduced the impact of an unavoidable frontal collision compared to you just leaving the cruise set at ??mph you were going and smashing into them without slowing down. By definition, AEB worked flawlessly.

Nowhere does it state that AEB will 100% avoid any frontal collision.

 

[yobigd20]

Nope. he did not brake.

well now you are misquoting him and deleting a word. his actual original post said:

i did not manually step on the brakes at all, even "until" the end.

you deleted 'until' and combined with the title 'TACC failed to brake' for me translates that TACC failed to brake and he had to manually brake at the end.

 

[green1]

you deleted 'until' and combined with the title 'TACC failed to brake' for me translates that TACC failed to brake and he had to manually brake at the end.

No, I didn't delete a word, I quoted a different post. and even in the one you quote he still says that he didn't hit the brakes at all (You accuse me of deleting "until" while you ignored "even")

Nowhere does he claim to have ever touched the brakes prior to the vehicle coming to a full and complete stop.


full post I quoted was:

I did not brake at all, even at the end. I wanted to show my friend the TACC so I literally let it do its thing. The only thing I did was swerve to the right. I cut the video off, but after the vehicle stopped, it started moving forward again so I applied the brakes to turn off TACC.

As for the thread title, it's sensationalism and should really be changed by a moderator to more accurately describe the situation. But even so, it is technically true. TACC didn't brake, but emergency braking did.

 

[yobigd20]

No, I didn't delete a word, I quoted a different post. and even in the one you quote he still says that he didn't hit the brakes at all (You accuse me of deleting "until" while you ignored "even")

Nowhere does he claim to have ever touched the brakes prior to the vehicle coming to a full and complete stop.

i guess that depends on how you interpret the statement. i interpret 'until the end' meaning that right at the end he had to brake manually.

 

[jgs]

i guess that depends on how you interpret the statement. i interpret 'until the end' meaning that right at the end he had to brake manually.

OP's followup (TACC failed to brake at stop, nearly accident. - Page 2) eliminates the ambiguity present in the original post. Followup says "I did not brake at all, even at the end."

 

[yobigd20]

OP's followup (TACC failed to brake at stop, nearly accident. - Page 2) eliminates the ambiguity present in the original post. Followup says "I did not brake at all, even at the end."

lol thx, missed that post.

 

[MrClown]

Look at post #11 for clarification that he did not use the brake at all. "I did not brake at all, even at the end. I wanted to show my friend the TACC so I literally let it do its thing. The only thing I did was swerve to the right."

Also note that emergency braking and TACC are two different things. TACC didn't know he was no longer following the Prius to the right but emergency braking did work as (or better than) designed by avoiding the collision.

It's an understandable mistake given that TACC is expecting a highway rather than surface streets, at least for now. Elon and Tesla documentation have both stated this. There are many scenarios where TACC doesn't work well on surface streets. On a surface street, the car you are following leaving your street in any direction is one of the main things that confuses TACC in my experience. It generally seems to expect you to follow that car so when you don't, you get the OP's situation. The moral of the story is to use TACC with caution and awareness, especially if you decide to use it on the surface streets it isn't designed for.

---

Edit: Too many posts on here too quickly. I see the confusion over the OP's braking was already cleared up before I entered my post.

 

[SomeJoe7777]

I agree with RacerX. Cruise control is meant for highway driving. TACC is a more advanced cruise control that solves a problem that regular cruise control has: other cars that aren't traveling at exactly the same speed as you are. Under that condition on the highway, you are frequently tapping the brakes to disengage cruise control in order to position your vehicle properly and safely within the traffic flow. Then, after you move around and get into the clear again, you resume cruise control.

TACC is a driver assistance feature to remedy that situation. No longer do you have to disengage/resume because of traffic. However, TACC is still <i>cruise control</i> at heart. On any street where you wouldn't use regular cruise control, I believe that's a street that TACC shouldn't be used on either.

For me, this translates to: Any street that isn't a controlled-access highway or any street with traffic lights = no cruise control, and no TACC.

 

[MrClown]

For me, this translates to: Any street that isn't a controlled-access highway or any street with traffic lights = no cruise control, and no TACC.

I use CC (and now TACC) on surface streets to help prevent accidental speeding. I don't, however, expect it to do all the braking for me. I've learned most of where it will and won't work by playing with it and being very prepared for it to get confused. I expect to disable or override it regularly as needed. I wouldn't have been as brave as the OP to let the car do its thing in that case though.

 

[LetsGoFast]

TACC does not see stationary objects? That's not been my experience. That also means stop-and-go traffic wouldn't work, which it does.

If an object is moving when TACC acquires it, it continues to be aware of that object when it comes to a stop. If it is not moving when TACC first sees it, it ignores it.

 

[eye.surgeon]

Bottom line, TACC is for highway use as Tesla has stated. i use mine sometimes on surface streets but don't expect perfection and wouldn't call it a failure when it isn't perfection when used off-label.

 

[green1]

Any moderator want to change the title so that it's better reflective of what happened? It still implies that the user had to prevent an accident when in fact the car did so all on it's own.

how about something like "TACC didn't brake at stop light, Automatic Emergency Braking prevented collision"
I know it's not as attention grabbing, but it's much more accurate and less inflamatory.

 

[LetsGoFast]

TACC didn't know he was no longer following the Prius to the right but emergency braking did work as (or better than) designed by avoiding the collision. [/QUOTE]

Actually, TACC knew that the Prius had pulled out of his lane and didn't recognize the parked white car as something to stop for. If TACC reacted to stationary returns, it would slam to a stop for all kinds of crazy non-events. A car has to be moving for TACC to process it, which is how all such radar-based systems work. If vision processing is added for some future auto-pilot release, it might deal with that situation -- but no current production adaptive cruise control would do anything different.

 

[MrClown]

Actually, TACC knew that the Prius had pulled out of his lane and didn't recognize the parked white car as something to stop for. If TACC reacted to stationary returns, it would slam to a stop for all kinds of crazy non-events. A car has to be moving for TACC to process it, which is how all such radar-based systems work. If vision processing is added for some future auto-pilot release, it might deal with that situation -- but no current production adaptive cruise control would do anything different.

I don't disagree about stopping for parked cars in general but I'm not sure how you can say that TACC knew not to follow the Prius anymore. Neither of us knows for sure what the TACC actually thought here. We can't even see what the indicator was on the dash. Based on the video and my experiences with TACC, it looks to me like the Prius was sufficiently in front of the car for TACC to stay locked on to it, thinking it was just going around a bend past some stopped/parked cars. Either way, it doesn't really matter. The point is that this is simply another example scenario (out of many) for why we should not expect TACC to work well on surface streets. We can use it on surface streets at our own risk but we should be very prepared to intervene often.

 

[LetsGoFast]

Either way, it doesn't really matter. The point is that this is simply another example scenario (out of many) for why we should not expect TACC to work well on surface streets. We can use it on surface streets at our own risk but we should be very prepared to intervene often.

I think we are broadly in agreement and you are correct that there is no way to be certain with the information we have if it believed that the Prius had changed lanes or if it believed it was still following it. It is mostly irrelevant anyhow.

 

[joer00]

I had the exact same experience, HOWEVER what is very very strange is that it only happens when the car in front turns to the RIGHT. When it turns to the left I experience the OPPOSITE. The car is already out of my lane and TACC slams on the brakes !

I will see if I can make some tests to prove this. So far TACC works for me perfect since the latest update, very smooth ! Cars leaving lanes is the only situation where it fails.

 

[Lintrix]

OP - are you on 6.2 or are you on 6.1?

I'm on v6.2 (2.4.153) which i believe is the latest update.

So emergency braking worked better than advertised, and TACC worked exactly as advertised.

The problem here isn't in the systems, or in the advertising, it's in people having expectations that are ahead of what's currently being offered.

Actually now that you mention it, it can't be the emergency brake happening because i clearly had to swerve and "sharply turn the wheel" which should have actually cancelled the emergency brake. I never applied the brakes myself. Maybe it was just the TACC braking.

Any moderator want to change the title so that it's better reflective of what happened? It still implies that the user had to prevent an accident when in fact the car did so all on it's own.

how about something like "TACC didn't brake at stop light, Automatic Emergency Braking prevented collision"
I know it's not as attention grabbing, but it's much more accurate and less inflamatory.

I did in fact have to prevent an accident. Had I not swerved to the right, there was still a big chance the accident could have happened. Whatever emergency braking that happened *MAY* have stopped the car centimeters before the collision, it surely didn't feel like it could have stopped on time.

@Lintrix - First of all, why in the hell are you using TACC on a clearly congested surface street? If you do make the poor decision to use this you NEED to maintain control of the vehicle. There are too many variables that I don't think any computer algorithm can account form.

That street is not even close to being congested. To be fair, the car may perform better on a congested street because maybe there would be more data points for the sensors to follow. To answer your question, I have been using TACC on major streets for a long time now. It is very convenient and I have been a proponent and supporter of the autopilot developing / releasing since the very beginning. As soon as TACC was released through software update, I started using it to get used to it and learn all the different quirks it has so I know what to expect. I don't expect TACC to drive for me but there are certain things that you learn to expect when you use it. One of them is to be able to track cars in front of you and to trust the vehicle to come to a stop when travelling at slow speeds. I am not asking for it to stop for me while I am going 55 mph into a car that's stopped at a red light. This is actually very normal driving conditions that I have been using TACC for for awhile now.

 

[green1]

I

I did in fact have to prevent an accident. Had I not swerved to the right, there was still a big chance the accident could have happened. Whatever emergency braking that happened *MAY* have stopped the car centimeters before the collision, it surely didn't feel like it could have stopped on time.

I see it a little differently. I see that Automatic Emergency Braking managed to stop you DESPITE you swerving, not because you swerved.

I suspect had you not swerved, it would have stopped with slightly (though not much) more room that it did. In this case AEB worked very well.

And it's not SUPPOSED to give you lots of room, it says right in the product description that it only activates once a collision is UNAVOIDABLE. Honestly, it sounds like AEB activated too early if anything. (Which is actually a good thing I think, but it is more aggressive than it claims to be)

 

[dsm363]

well, to be clear, I would say it's not really the TACC system that failed, but rather the "automatic emergency braking" system that failed.

whatever you want to call it, it's brand new in 6.2, and it failed to stop. that's pretty damn clear to me that it's a massive failure of the reliability of the system, especially when they go around touting the feature in the release notes.

View attachment 77886

actually, before I even say any more about this feature failing, OP - are you on 6.2 or are you on 6.1?

Note it says to 'reduce the impact', not eliminate it for an unavoidable accident.

 

[GregTexas]

Volvo is claiming by 2020 there will be zero fatalities in their cars built from that point on. No stopping on train tracks.