Cruise control inappropriately slamming on brakes

[KenC]

It's a subjective observation. When it comes as a surprise, the perception is that it is much more aggressive than if one is expecting it. But for me, it is some fairly aggressive braking: so much so that I have semi-seriously considered getting a light-up sign to put in the rear window: "Sorry: it's not me, it's the f-ing car."

How about, "My car is possessed!"

 

[Kevy Baby]

How about, "My car is possessed!"

There are a lot of colorful things I would possible display, but in deference to others, I think I shall forgo them.

 

[Stach]

You shouldn’t use TACC on two lane roads. Period. Depending on the aspect of the car ahead, the system may apply brakes. I’ve played with it some on two lane roads when there is no one behind me and it’s better than it was earlier this year. On multi lane roads, it works great.

We have probably the most advanced car on the road today, and the recommendation is to not use cruise control on 2-lane roads because Tesla's TACC (in beta) is too dangerous? So while I've been using cruise control from other manufacturers on 2-lane roads for 40+ years, I shouldn't use Tesla's? It is absolutely Ridiculous that Tesla hasn't fixed TACC or given us the option to use dumb cruise control!

 

[PianoAl]

 

[Tres_Azul]

+1 for needing regular 'dumb' cruise control. I would happily give up both AP & TACC for it. (not range tho...)

Also, +1 that even one phantom braking event, in one production model 3 automobile, is 1000% too many. I don't understand how they are getting away with this nonsense.

The only saving grace here for me is that I love the way the RWD variants of the 3 drive, especially the lighter SR+ I bought. (like the extra speed and better stereo of the LR, but dislike the AWD handling at the limit and could not justify cost of the P as a commuter.) So the bunk TACC/AP isn't a huge loss, as much as it is a serious disappointment and ongoing source of aggravation/frustration.

 

[mddmx]

You want me to spend $10K on FSD, this phantom braking gives me 0 confidence that you know what you are doing

 

[strider]

I've experienced phantom braking, and the slowdown is relatively dramatic.

But I wouldn't describe it as "slamming on the brakes." Are other people's experiences more radical than mine? No locked wheels, right?

Not doubting people, just want to quantify it.

No locked wheels, ABS and all... I think we're feeling the same thing. I agree w/ @Kevy Baby. I think that since it is unexpected it feels worse than it is. That being said it is way more than just regen. It is hitting the brakes. When it happens it elicits an audible yelp from my passengers.

 

[KuramaKitsune]

Hi, first post here.

I'm having significant issues with the adaptive cruise control. There is a 2 lane road near me with a 50 limit, and I like to set the cruise to stop me speeding. However, on a couple off occasions the cruise control has hammered on the brakes when a truck has been coming the other way - despite being safely and completely in its own lane.

I have had the same thing on motorways; overtake something, then pull back into the middle lane with a lorry in the inside lane. The cruise control seems to think that I am going to drive into the lorry and, again, hammers on the brakes.

It is lucky that I haven't had anyone smash into the back of me. I've had to stop using cruise on 2 lane roads and hover my foot over the accelerator when anywhere near a lorry on the motorway in case it decides to randomly fire me through the windshield.

Am I alone in this?

hell this happened to me this morning, on the leftmost lane of a 4 lane highway
it was easily enough to jerk my body forward
just like someone TAPPED the brake real hard for a split second

 

[KuramaKitsune]

come to think of it..
i Think i saved that tesla cam footage to the ssd
ill have to review that...

 

[alexgr]

Thanks all, looks like I'll have to put up with it for a while at least. It's a shame - this and the blooming automatic wipers are distracting from what has been an otherwise fantastic car.

Finally "2 lane road huh. Doesn't that still fall under the warning limitation in the manual?"

No. It says "Traffic-Aware Cruise Control is primarily intended for driving on dry, straight roads, such as highways and freeways. It should not be used on city streets."

So maybe my UK A road doesn't fit with that, but its the emergency stops on the motorways (freeways) that are most likely to cause an accident and concern me most.

Plus - I'd like a modern car to behave at least as well as my old ones.....

It is great if your old cars had TACC capable of flawlessly following a narrow road. In Germany, I would be afraid to use any automation on any road other than Autobahn, the roads are generally too narrow in Europe.
That said, I do occasionally have phantom braking even without any traffic.

 

[FringeGlock]

Hi, first post here.

I'm having significant issues with the adaptive cruise control. There is a 2 lane road near me with a 50 limit, and I like to set the cruise to stop me speeding. However, on a couple off occasions the cruise control has hammered on the brakes when a truck has been coming the other way - despite being safely and completely in its own lane.

I have had the same thing on motorways; overtake something, then pull back into the middle lane with a lorry in the inside lane. The cruise control seems to think that I am going to drive into the lorry and, again, hammers on the brakes.

It is lucky that I haven't had anyone smash into the back of me. I've had to stop using cruise on 2 lane roads and hover my foot over the accelerator when anywhere near a lorry on the motorway in case it decides to randomly fire me through the windshield.

Am I alone in this?

Do not know, but it may have to do with you driving on the left side of the road and the person that wrote that program drives on the right side of the road. I drive on the right side of the road and have engaged the auto pilot on a winding, undulating 2 lane road. As the vehicle was approaching a curve, it started to cross a solid, doulbe yellow line in the center of the road. Fortunately there was no oncoming traffic and I brought the car back into the right lane. Do not know why the car did that. It does not inspire confidence in the FSD program. The car also seriously brakes when it "sees" a rise in the road.

 

[PianoAl]

But I wouldn't describe it as "slamming on the brakes."

Well, the car did indeed do what I would describe it as slamming on the brakes.

 

[Kevy Baby]

Well, the car did indeed do what I would describe it as slamming on the brakes.

When you start arguing with yourself, it may be time to seek professional help

 

[rincewind]

I've had a full emergency stop event - and I wasn't using TACC at the time. I was gound around a large roundabout, with traffic lights at various points. I was slowing at about 20mph when the car got it into its computer that the deceleration wasn't fast enough. It slammed on the brakes, as in hanging out of the seat belt for a moment. Fortunately there was no car behind me. It's the only time it's done it on 12k miles, but it was something of a surprise.

 

[Sans-gas]

I’ve had my M3 brake suddenly several times, but not to a complete stop, when using basic AP on 2 lane roads. I, too, am selective when I use it and now aware of where it may have issues. Going under underpasses and bridges casting sharp shadows I am watchful (of cars behind) or flick it off. After 22K miles, I can predict issues. Oh my, but I can put up with all of them. I’d not give the car up for anything.

 

[KenC]

I’ve had my M3 brake suddenly several times, but not to a complete stop, when using basic AP on 2 lane roads. I, too, am selective when I use it and now aware of where it may have issues. Going under underpasses and bridges casting sharp shadows I am watchful (of cars behind) or flick it off. After 22K miles, I can predict issues. Oh my, but I can put up with all of them. I’d not give the car up for anything.

I just wish Tesla would publish a list of edge cases that owners should be extra cautious about, since all of us are like beta testers learning these edge cases ourselves.

When I hit these edge cases, I just push on the accelerator to override potential braking.

 

[EV Promoter]

Yes, many of us are now asking for a dumber cruise control that mostly just follows distance with the radar, because of these phantom braking issues. Mind you, I would prefer that the issues would just be fixed but it'S a very difficult problem to solve. In the meantime, I would take a TACC that doesn't provide as much safety features (** because of the false positives **).

Such a request is simply impossible to satisfy because TACC is just a part of an integral algorythm and approach in Tesla.

The only feature request we can forward is the Disable Adaptivity Option to the TACC, something that is present in every Adaptive Cruise Control system, giving us a simple Non-adaptive Cruise Control for people that don't wont to be beta testers for a system that doesn't work reliably yet.

Let's say the rewrite of the rewrite of the rewrite one day will give, 100% sure, the most fantastic TACC, AP, FSD: in the meantime gives us a standard fuc*ing non adaptive CC!

 

[EV Promoter]

View attachment 602836

Allow me to use it as avatar

 

[EV Promoter]

+1 for needing regular 'dumb' cruise control. I would happily give up both AP & TACC for it. (not range tho...)

Also, +1 that even one phantom braking event, in one production model 3 automobile, is 1000% too many. I don't understand how they are getting away with this nonsense.

THIS

 

[PianoAl]

>>Well, the car did indeed do what I would describe it as slamming on the brakes.

>When you start arguing with yourself, it may be time to seek professional help

LOL. I meant to write "Well, yesterday the car did indeed ..."

IOW, it was the most dramatic phantom braking that's happened in the ten months we've had the car.