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Phantom braking is the biggest issue with AutoPilot.

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Yepp, frequent phantom braking is why we don't use cruise. It's a shame, we really wanted adaptive cruise from a new vehicle purchase. My wife gets to drive regular rental vehicles often for work and has never experienced phantom braking in those vehicles that have adaptive cruise (nor the general twitchiness of cruise in the Model 3 of course). It's actually what made her want adaptive cruise on our next vehicle. The Model 3 doesn't have "normal" non-adaptive cruise, so we effectively don't have usable cruise control on our 2019 car. Big bummer.

Over a 50/60km highway trip (typically work day for us), we get probably 3-10 phantom braking events. Some in routine spots (inconsistently though), some random spots. No overpasses here, so it's not that common problem. In some cases, it seems like it doesn't understand cars (especially semis) in opposing traffic are in different lanes going around corners, and slams on the brakes. Other times, it seems unknowable as to what caused it. We've been nearly rear-ended (aggressive tailgating work rush traffic, gotta deal with it), it's just not worth using.

Of course, I can lightly ride the throttle to prevent braking, but then why don't I just... apply throttle without cruise?

EDIT: Ah, yes, as others mentioned, the over-reacting to vehicles slowing down as well. I get this is hard though, human drivers gamble that the vehicle in front will successfully get out of the way and not have to keep slowing down directly in front of them. The Model 3 does not, which is understandable but very annoying.
 
Can you please elaborate on when it is likely to phantom brake? I haven't been able to predict its behavior. Thanks.

1). When a car crosses in front of you at an intersection, even at a distance
2). When a car moves from your lane to an exit lane and is slow to completely leave your lane
3). A shadow from an overpass

These are the most common to me. If I think of more I will add to this.
 
1). When a car crosses in front of you at an intersection, even at a distance
2). When a car moves from your lane to an exit lane and is slow to completely leave your lane
3). A shadow from an overpass

These are the most common to me. If I think of more I will add to this.

Y'know, I totally forgot about point 1 being a thing since I don't use it in town anymore. Good reminder. Setting the follow distance to the minimum helps, but I rarely want it at the minimum.
 
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1). When a car crosses in front of you at an intersection, even at a distance
2). When a car moves from your lane to an exit lane and is slow to completely leave your lane
3). A shadow from an overpass

These are the most common to me. If I think of more I will add to this.

Thanks, yes those are situations I have noticed also, to the point that I find it easy to just turn AP off when there is a lot of merging traffic around me.

The one thing that freaks out my family and to some extent me is the completely random brakes I have had outside of the above situations. It has only happened 4-5 times in the 5000 miles we have driven the car, but it is a bit unnerving when it happens. Bright daylight, well marked 5-lane Interstate, pretty much no cars ahead for at least half a mile, and the car brakes momentarily. Although there was no car behind us in most situations, there was one incident where there was a car behind us and I was worried about road rage.
 
1). When a car crosses in front of you at an intersection, even at a distance
2). When a car moves from your lane to an exit lane and is slow to completely leave your lane
3). A shadow from an overpass

These are the most common to me. If I think of more I will add to this.

There are so many other random instances, though. A concrete wall to the left of the left lane and it hammered the brakes for me yesterday.
 
Although there was no car behind us in most situations, there was one incident where there was a car behind us and I was worried about road rage.

I'll be picking up my M3 this week and my old Model S didn't have autopilot so I'm excited to try it out finally. Phantom breaking is the biggest thing I hear about that gives me any worries at all. Is this like SLAMMING on the breaks? Like someone following you on the highway could rear-end you? Or..just normal breaking that other drivers can just deal with and move away from (even if moderately annoying)?
 
I'll be picking up my M3 this week and my old Model S didn't have autopilot so I'm excited to try it out finally. Phantom breaking is the biggest thing I hear about that gives me any worries at all. Is this like SLAMMING on the breaks? Like someone following you on the highway could rear-end you? Or..just normal breaking that other drivers can just deal with and move away from (even if moderately annoying)?

It varies, but when I talk about and how most others talk about it is referring to situations where it's sudden and hard braking, but brief. Using full regen plus some friction brakes. Not eased on, all at once. And it stops within a second or so to accelerate again (very suddenly as well), so the feeling it gives is very whippy. Drops about 10 mph during a phantom braking event, I'd say? (when going about 50mph to start with)
 
Yes you should. It's quite easy for most. Just like old fashioned cruise control was useful for those who figured out you had to brake so it wouldn't rear end cars in front of you.
The difference between old-style cruise control and AP is that matching traffic flow by automatically braking and accelerating was not a feature of old-style cruise control. Therefore, a driver using old-style cruise control knew they were required to brake to avoid rear ending a car in front.

On the other hand, AP is designed to brake and accelerate to follow the flow of traffic. This is a fundamental difference from old-stye cruise control, and it's precisely why a driver using AP should not have to brake or accelerate to overcome the deficiency of the AP system.

Some will not have the ability to do so. Maybe you are in that group.
Some are Tools. Maybe you are in that group.
 
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I've taken my M3 up and down the 5 in the top two states and not once had an issue with any braking that I could not tell you exactly why it occurred, so not a lick of it was phantom.Tough thing is that all claims in both directions here are purely anecdotal. Maybe we need to also hear from all the folks who have never or rarely encountered unexpected braking or encounter less than their old TACC car did.

Many of the problems I've seen are driver-oversight issues (the driver didn't see something or drives a certain way normally and expects the car to drive the same way). Many are caused by the auto-driver-disconnect - the difference in perception between when the car is doing something versus the driver anticipating an action. This is also why passengers in high acceleration will more easily experience vertigo than the driver, since the driver anticipates it.

I've noticed that you can definitely tell when your TACC is following a gas pulser or other such fail-driver. Horrible way of driving and usually I just end up either going around them or letting somebody else get between me and them. ALL TACC will try to precisely follow the car in front. Follow an idiot and your car is basically stuck on a stick to the back of an idiot driver.

Slowing for a car in front of you at an intersection? ... "AS/TACC/AP is meant to be used on access-controlled roadways" and "AS/AP/NOAP is in beta". So you're complaining about a Beta (Definition of Beta: Unfinished, bugs-possible, feel free to try it but it's not done yet, so keep your hands on the wheel) feature used in an environment that it's not meant for. Kind of like complaining about a prototype vacuum cleaner having a hard time on your lawn. If you want to use beta software outside its intended purpose, then expect it to not respond the way you think it will. And if you were driving and that turning car suddenly dropped its engine, would you have time to stop? The Tesla sees obstruction and anticipates it remaining, so makes sure it can accommodate it if it does, whereas many drivers expect the turning car to clear the way and would end up stopping very quickly when they collide with a turner who doesn't.

Slowing when a car moves from your lane into an exit and hasn't left your lane yet... Yeah, it SHOULD slow down for that. As a responsible and well-trained driver, I slow down for that. I'm not going to rush up on somebody slowly going into the exit lane because I never know if they're going to clear in time, or if they might not even realize they're in the wrong place and need to rush back into my lane. That slowdown is just smart. Not like it won't pick back up again when the other car is clear.

Slowing down after an assisted lane change? ... Completely normal because it does an overtake when doing the lane change. Speed set to 65 and when changing lanes, it will speed up to 68-70 depending on circumstances. Then it regens back down to the set speed. Or if there is a car close ahead of you in the new lane, it slows to the follow distance behind it.

And I'd love to see video - even TC video - of it "hammering on the brakes in response to a concrete wall to the left of the lane". I anticipate a potential for exaggeration about "hammering on the brakes" (I've seen people call normal slowing for the car in front 'unexpected braking'), and also a potential for the driver having been distracted by the beautiful wall and missing something else that the car saw.
 
It would be nice if when using only TACC it would tone down the phantom braking. I get the feeling that Tesla is trying very hard to keep Autopilot safer than driving without it but some people are getting into accidents because they're not paying attention. That means they have make the car more cautious to compensate.
 
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I don't have Noa so my Ap disables as soon as I hit the blinker, this switches it over to standard adaptive cruise (which I can report has the same bugs). It's like it stumbles over the line when switching lanes sometimes. I've learned that if I lane change a mile behind the car I intend to pass, then it seems fine but if I'm even remotely in the vicinity of the car in front (like 6+ car lengths), it will hesitate as my car makes it about 3/4s into the lane beside me. It's like it decides last minute that I'm just a wee bit closer than it would like and it needs to slow me down for a fraction of a second. I did have one occasion, no cars near me (luckily) that adaptive cruise completely disable on its own which of course immidiately turns on full regen braking, that was a bit of a surprise. I've learned that if the lines on the road aren't perfect, if there is a car nearby or if there are shadows on the road, I should hover my foot over the gas, not exactly the ideal stress free experience you'd want.

I don't want the car to disable emergency braking but I'm not convinced that's what the hiccup is. I think it just drops the accelerator for a split second which then engages regen. I don't think it's actually seeing something and emergency braking because it's not braking THAT hard but full regen without you expecting it is still braking enough to be jarring.

Next road trip I take, I'm going to plan for some range loss and disable regen then try again. Im confident the cruise and Ap hiccups will be much less noticeable then.
 
I've taken my M3 up and down the 5 in the top two states and not once had an issue with any braking that I could not tell you exactly why it occurred, so not a lick of it was phantom.Tough thing is that all claims in both directions here are purely anecdotal. Maybe we need to also hear from all the folks who have never or rarely encountered unexpected braking or encounter less than their old TACC car did.

Many of the problems I've seen are driver-oversight issues (the driver didn't see something or drives a certain way normally and expects the car to drive the same way). Many are caused by the auto-driver-disconnect - the difference in perception between when the car is doing something versus the driver anticipating an action. This is also why passengers in high acceleration will more easily experience vertigo than the driver, since the driver anticipates it.

I've noticed that you can definitely tell when your TACC is following a gas pulser or other such fail-driver. Horrible way of driving and usually I just end up either going around them or letting somebody else get between me and them. ALL TACC will try to precisely follow the car in front. Follow an idiot and your car is basically stuck on a stick to the back of an idiot driver.

Slowing for a car in front of you at an intersection? ... "AS/TACC/AP is meant to be used on access-controlled roadways" and "AS/AP/NOAP is in beta". So you're complaining about a Beta (Definition of Beta: Unfinished, bugs-possible, feel free to try it but it's not done yet, so keep your hands on the wheel) feature used in an environment that it's not meant for. Kind of like complaining about a prototype vacuum cleaner having a hard time on your lawn. If you want to use beta software outside its intended purpose, then expect it to not respond the way you think it will. And if you were driving and that turning car suddenly dropped its engine, would you have time to stop? The Tesla sees obstruction and anticipates it remaining, so makes sure it can accommodate it if it does, whereas many drivers expect the turning car to clear the way and would end up stopping very quickly when they collide with a turner who doesn't.

Slowing when a car moves from your lane into an exit and hasn't left your lane yet... Yeah, it SHOULD slow down for that. As a responsible and well-trained driver, I slow down for that. I'm not going to rush up on somebody slowly going into the exit lane because I never know if they're going to clear in time, or if they might not even realize they're in the wrong place and need to rush back into my lane. That slowdown is just smart. Not like it won't pick back up again when the other car is clear.

Slowing down after an assisted lane change? ... Completely normal because it does an overtake when doing the lane change. Speed set to 65 and when changing lanes, it will speed up to 68-70 depending on circumstances. Then it regens back down to the set speed. Or if there is a car close ahead of you in the new lane, it slows to the follow distance behind it.

And I'd love to see video - even TC video - of it "hammering on the brakes in response to a concrete wall to the left of the lane". I anticipate a potential for exaggeration about "hammering on the brakes" (I've seen people call normal slowing for the car in front 'unexpected braking'), and also a potential for the driver having been distracted by the beautiful wall and missing something else that the car saw.

For the prior 3.5 years with my Golf R, I had precisely zero phantom braking events in that car, for 20k miles total. With the Model 3 in 2k miles, I’ve had more than I can count. Some subtle, some very aggressive, and precisely zero are user error. That’s why they’re called “phantom” braking events, and that’s why so many complain about it.

Adaptive cruise control should work just fine, like it does in literally any other car with ACC.
 
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I've taken my M3 up and down the 5 in the top two states and not once had an issue with any braking that I could not tell you exactly why it occurred

...

So you're complaining about a Beta (Definition of Beta: Unfinished, bugs-possible, feel free to try it but it's not done yet, so keep your hands on the wheel) feature used in an environment that it's not meant for.

...

And I'd love to see video - even TC video - of it "hammering on the brakes in response to a concrete wall to the left of the lane". I anticipate a potential for exaggeration about "hammering on the brakes" (I've seen people call normal slowing for the car in front 'unexpected braking'), and also a potential for the driver having been distracted by the beautiful wall and missing something else that the car saw.

Regarding the I-5, perhaps that makes sense you encounter less issues. The highways I drive have many more turns than the I-5 does (well, IIRC, closer to Seattle there's quite a few, not to mention the construction), plus opposing traffic is not separated with a barrier.

Regarding beta software, fair point but... give me a non-beta option? Why can't I have standard non-adaptive cruise? Or perhaps give a setting for "smoothness" or the adaptive cruise? Everybody knows how to handle traditional cruise safely, and emergency forward collision mitigation can still be enabled for when drivers aren't reacting in time.

Regarding video, I'm doing a lot of driving in the next few weeks. I'll try to use AP more than usual and see if I can get some clips with a camera pointed at the display as well (apparently I need to demonstrate that Autosteer is cutting lanes on highways here as well).

...

I did have one occasion, no cars near me (luckily) that adaptive cruise completely disable on its own which of course immidiately turns on full regen braking, that was a bit of a surprise.

...

I've had this happen once too! Once to me, once to my wife (happened within the same week). Just completely dropped with no sound alert (it did show on screen that cruise was disabled though, but no audio alert!).

For the prior 3.5 years with my Golf R, I had precisely zero phantom braking events in that car, for 20k miles total. With the Model 3 in 2k miles, I’ve had more than I can count. Some subtle, some very aggressive, and precisely zero are user error. That’s why they’re called “phantom” braking events, and that’s why so many complain about it.

Adaptive cruise control should work just fine, like it does in literally any other car with ACC.

Right, yeah. Again, my wife has driven various brands via rentals with adaptive cruise. She had no issue with phantom braking. It is unsurprising that your Golf had no phantom braking issues. Phantom braking is very much a Tesla problem -- other manufacturers released non-updateable but well-behaving adaptive cruise. Giving Tesla an excuse for something as "simple" as adaptive cruise (which they've had a few years to get right at this point, with a lot of data) just because it's "beta" is giving them too much slack. This misbehaving feature is dangerous and will result in being rear-ended at some point, thankfully drivers are attentive enough to generally slam on their brakes as well to avoid hitting us.

Tesla, please give us non-adaptive traditional cruise while your more advanced systems are in beta.
 
It’s a great car. The Model 3 puts it to shame and makes it feel super outdated. But the ACC worked flawlessly. And it let you sit back further than whatever “7” means in the Model 3. I would prefer to be able to be further back from the vehicle in front.

Following a motorcycle the other day, I realised just how close the max of "7" puts you. It can be uncomfortable, but it really depends on the speed. I tried for about 10 mins but felt I was getting way too close to the motorcycle for his safety.
 
Not excusing the behavior at all, but it's relevant to note phantom braking is present in most Adaptive Cruise Control systems. We had this issue in other cars, as well. There's at least one class action lawsuit against Honda for this very issue. It's not a Tesla-specific problem. Hopefully Tesla will ultimately sort it out and improve it with an update.

https://www.classlawgroup.com/wp-content/uploads/Honda-CR-V-Automatic-Braking-Lawsuit-Complaint.pdf

the Class Vehicles to fluctuate their highway speed without warning when adaptive cruise control is set, and (3) Class Vehicles alerting drivers to apply brakes immediately although no obstruction is present.
 
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Not excusing the behavior at all, but it's relevant to note phantom braking is present in most Adaptive Cruise Control systems. We had this issue in other cars, as well. There's at least one class action lawsuit against Honda for this very issue. It's not a Tesla-specific problem. Hopefully Tesla will ultimately sort it out and improve it with an update.

https://www.classlawgroup.com/wp-content/uploads/Honda-CR-V-Automatic-Braking-Lawsuit-Complaint.pdf

the Class Vehicles to fluctuate their highway speed without warning when adaptive cruise control is set, and (3) Class Vehicles alerting drivers to apply brakes immediately although no obstruction is present.

Thanks for the link. Hondas were not evaluated by my wife's common rental situations since I don't think I've ever seen a rental Honda.

Here's an... interesting quote.

"""
Indeed, Plaintiff Cadena’s 2017 Honda CR-V Touring repeatedly alerted her of problems with Honda Sensing safety and driver-assistive system, accelerated and slowed unprompted, even though there was no obstruction ahead, and instructed her to apply breaks, even though another vehicle was at least fifty (50) feet ahead.
"""

50 feet ahead at what speed? At highway speeds and depending on the relative speeds for the cars, that might be warranted. 50 feet isn't that far. However, this only mentions the vehicle instructed them to apply brakes and didn't do what we're talking about with Tesla applying the brakes. Also, this lawsuit sounds frivolous as heck given that statement :D

"""
Likewise, Plaintiff Patel’s 2017 Honda CR-V EX-L repeatedly alerted him of problems with Honda Sensing safety system or that the vehicle’s radar was obstructed, even though in fact there was no obstruction of the radar, and Plaintiff Geiger’s 2017 Honda CR-V EX-L repeatedly alerted him of problems with Honda Sensing safety and driver-assistive system by displaying numerous fault messages on the vehicle’s instrument cluster.
"""

Well, dirt? Bugs? How real is the lack of obstruction? Tesla has the same problem in this case.

"""
repeatedly instructed Ferguson to apply breaks and reduced its speed even though there was no obstruction ahead, and Honda Sensing safety and driver-assistive system continued to malfunction even after Ferguson disabled it.
"""

Again, instruction not action.


"""
For instance, on March 12, 2017, one driver posted on a CR-V enthusiast website that while driving his/her 2017 Honda CR-V EX “all of a sudden many systems started reporting problems on my dashboard, all at the same time”
"""

Instruction, not action...

"""
TRAVELING ON INTERSTATE AT THE SPEED LIMIT THE CAR SUDDENLY BRAKED. ALL SAFETY SYSTEMS WERE ACTIVATED AT THIS TIME. FORTUNATELY THERE WAS NO TRAFFIC IN FRONT, BEHIND OR BESIDE. I GOT THE CAR UNDER CONTROL , TURNED ALL SYSTEMS OFF AND PROCEEDED. MESSAGES ON DASH INDICATED FOUR SYSTEMS WERE INOPERATABLE
"""

Finally, some meat! Lacking any further info.

"""
THE ADVANCED SAFETY SYSTEMS THAT RELY ON RADAR (AUTO BRAKING, LANE DEPARTURE, ETC) ARE UNUSABLE IN VERY LIGHT SNOW. THERE WAS BARELY ANYTHING ON THE SENSOR COVER, YET THESE IMPORTANT SYSTEMS STOPPED WORKING. THIS HAPPENED REPEATEDLY THROUGHOUT THE DAY. WIPING THE SENSOR WOULD RESTORE FUNCTION, BUT ONLY FOR A COUPLE OF MINUTES, AT BOTH LOW SPEEDS AND ON THE HIGHWAY. THE VEHICLE HAS RECEIVED THE RECENT SOFTWARE UPDATE THAT WAS SUPPOSED TO FIX THIS. (TSB A17-064).”
"""

... ok? Maybe take control of your vehicle in snow. For what it's worth, my warning systems on my Honda didn't like snow either (but only warning systems, it does not have adaptive cruise or lane keep).

"""
WHEN THE CRUISE CONTROL (ADAPTIVE CRUISE CONTROL) IS ENGAGED, THE ACC CAN SOMETIMES JAM ON THE BRAKES WITH NO OBSTACLE IN THE PATH.
"""

Now we're talking!... but no further info.

"""
WAS DRIVING NORMALLY WHEN ABS, ADAPTIVE CRUISE CONTROL, LANE KEEPING ASSIST, AUTOMATIC EMERGENCY BREAKING, AND BREAKING SYSTEM "PROBLEM" LIGHTS LIT UP ALL AT ONCE. LIMPED THE CAR HOME.
"""

Welcome to limp mode. You had a problem with your car, and it took appropriate action.

"""
DRIVING HIGHWAY SUDDENLY CAR SLOWS AND DASH READS THAT ALL SYSTEMS- BRAKES, STEERING, AND, ETC FAILED. PULLED CAR OFF ROAD SAFETY. SHUT CAR OFF.RESTARTED. PROBLEM WENT AWAY. CHECKED ON HONDA OWNERS WEBSITE. THIS IS AN ONGOING PROBLEM WITH NO FIX. SCARY WHEN ALL SYSTEMS COULD BE COMPROMISED.
"""

Odd, but again, some fault happened. Did the engine shut off? That would certainly result in all lights going on and the car ceasing to accelerate.

Anyhow. I like tearing apart class actions like those related to "unintended acceleration". It seems like only a small chunk were reporting the car actually braking when it isn't supposed to, implying the problem isn't as frequent as the warning systems complaining more than they should. In Tesla's case, the phantom braking is significantly more common than forward collision alerts.
 
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