# Autopilot didn't stop on time



## Andy Kaplan

This morning, I was on autopilot on the highway in clear, sunny weather (and I was paying attention).

Suddenly, the car in front of me stopped short -- and autopilot didn't slow down fast enough. Once I realized that, I jammed on the brakes, but too late -- I hit the car in front of me.

Really confused about this. Presumably, the car is supposed to react faster than I can. I think that if I had been driving and slammed on the brakes, I might have avoided the accident.

Really just an FYI to the group. Not only should you always pay attention when using autopilot, we need to realize that it may not avoid accidents as well as (I) thought.


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## MelindaV

do you have the dashcam video?

and...


Andy Kaplan said:


> (and I was paying attention)





Andy Kaplan said:


> I think that if I had been driving and slammed on the brakes, I might have avoided the accident.


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## Andy Kaplan

Haven't pulled it yet, will check later. I didn't remember to push the "record" button until a while after, so I'm hoping it auto-saved when I put it in P.


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## MelindaV

Andy Kaplan said:


> Haven't pulled it yet, will check later. I didn't remember to push the "record" button until a while after, so I'm hoping it auto-saved when I put it in P.


the "recent" video will continue recording the p[rior 60 minutes, so if this has been more than an hour ago, it likely has been over written already.


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## Frully

It will come to a complete stop if there is time.

If it's automatic emergency braking where it determines it has a questionable amount of time to stop - it will ONLY BRAKE BY 30mph or 50km/h, relying on the driver to do the rest. This is to prevent getting rear ended further. If it slammed on the brakes down to zero speed for a false alarm it would likely cause a rear end accident.










https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf Page 91


> Automatic Emergency Braking The forward looking camera(s) and the radar sensor are designed to determine the distance from a detected object traveling in front of Model 3. When a frontal collision is considered unavoidable, Automatic Emergency Braking is designed to apply the brakes to reduce the severity of the impact. When Automatic Emergency Braking applies the brakes, the touchscreen displays a visual warning and sounds a chime. You may also notice abrupt downward movement of the brake pedal. The brake lights turn on to alert other road users that you are slowing down. If driving 35 mph (56 km/h) or faster, the brakes are released after Automatic Emergency Braking has reduced your driving speed by 30 mph (50 km/h). For example, if Automatic Emergency Braking applies braking when driving 56 mph (90 km/h), it releases the brakes when your speed has been reduced to 26 mph (40 km/h). Automatic Emergency Braking operates only when driving between approximately 7 mph (10 km/h) and 90 mph (150 km/h). Automatic Emergency Braking does not apply the brakes, or stops applying the brakes, when: • You turn the steering wheel sharply. • You press and release the brake pedal while Automatic Emergency Braking is applying the brakes. • You accelerate hard while Automatic Emergency Braking is applying the brakes. • The vehicle, motorcycle, bicycle, or pedestrian is no longer detected ahead. Automatic Emergency Braking is always enabled when you start Model 3. To disable it for your current drive, touch Controls > Autopilot > Automatic Emergency Braking. Warning: It is strongly recommended that you do not disable Automatic Emergency Braking. If you disable it, Model 3 does not automatically apply the brakes in situations where a collision is considered likely. Warning: Automatic Emergency Braking is designed to reduce the severity of an impact. It is not designed to avoid a collision. Warning: Several factors can affect the performance of Automatic Emergency Braking, causing either no braking or inappropriate or untimely braking, such as when a vehicle is partially in the path of travel or there is road debris. It is the driver's responsibility to drive safely and remain in control of the vehicle at all times. Never depend on Automatic Emergency Braking to avoid or reduce the impact of a collision. Warning: Automatic Emergency Braking is designed to reduce the impact of frontal collisions only and does not function when Model 3 is in Reverse. Warning: Automatic Emergency Braking is not a substitute for maintaining a safe traveling distance between you and the vehicle in front of you. Warning: The brake pedal moves downward abruptly during automatic braking events. Always ensure that the brake pedal can move freely. Do not place material under or on top of the Teslasupplied driver's floor mat (including an additional mat) and always ensure that the driver's floor mat is properly secured. Failure to do so can impede the ability


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## Andy Kaplan

Right -- but this was under autopilot, so I'd think it would do what was necessary to maintain the set gap and/or not crash. (If that's not the case, that should also be better explained and well broadcast, so that everyone knows that in an urgent slowdown situation, the driver needs to slam on the brakes right away.)


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## GateFather

Frully said:


> It will come to a complete stop if there is time.
> 
> If it's automatic emergency braking where it determines it has a questionable amount of time to stop - it will ONLY BRAKE BY 30mph or 50km/h, relying on the driver to do the rest. This is to prevent getting rear ended further. If it slammed on the brakes down to zero speed for a false alarm it would likely cause a rear end accident.
> 
> View attachment 28711
> 
> 
> https://www.tesla.com/sites/default/files/model_3_owners_manual_north_america_en.pdf Page 91


Wow this is very helpful - I did not know this myself. I've only had Emergency braking deployed once and I was doing under 35mph for sure. My son in the back seat said "Daddy look at that" - as soon as I took my eyes off of the car in front of me (which was a good 3-4 car lengths at that point) that car must have slammed on their brakes and within a second of turning my head to the side my car came lurching to a FULL stop probably less than an inch from the car in front of me. I was definitely going under 35mph but if I hadn't read the above, I would also have assumed the car would brake fully to 0mph from any speed to avoid an accident. Good to know and thanks for sharing.


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## Frully

The car can in theory see 2 cars ahead with autopilot but if the abrupt stop wasn't detected then AP doesn't stand a chance. 

AP is a lanekeeping and adaptive cruise system that cannot handle all traffic situations. The driver is still responsible for overseeing it.


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## sduck

I've had the car stop completely, abruptly, when the car in front of me stopped suddenly. And I have follow set on 1. Were there any other factors that might have caused this? Like maybe your foot was lightly touching the accelerator pedal or something.

I do know that my foot jerks up to the brake pedal instinctively when these things happen - is there any chance yours did the same, and perhaps lightly touched the brake pedal, just enough to take it out of AP (and auto-brake) before it had a chance to do it's thing?


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## Andy Kaplan

I have also had the car stop completely when the car in front of me stopped, which is partly why I was so surprised.

I really, really don't think my foot touched the accelerator on the way to the brake, but I suppose it's possible.


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## Love

So sorry to hear about your accident. I'll take it just a tiny OT here and say that I hope you, your passengers (if you had any) and anyone in the other vehicle are all OK and uninjured. 

Thank you for posting as a PSA to everyone. I've had the audible alert scare the crud out of me a few times but don't believe I've had any situations where AEB activated.


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## Andy Kaplan

THANKS to all for their best wishes -- I'm happy to report that everyone was fine, no injuries.


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## iChris93

Lovesword said:


> I'll take it just a tiny OT here and say that I hope you, your passengers (if you had any) and anyone in the other vehicle are all OK and uninjured.


I don't think that is off topic at all.


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## Frully

Lovesword said:


> So sorry to hear about your accident. I'll take it just a tiny OT here and say that I hope you, your passengers (if you had any) and anyone in the other vehicle are all OK and uninjured.


fwiw my reply came across as crusty...I normally (and should have) start with "Sorry this happened, hope you are okay"


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## sduck

Andy Kaplan said:


> I have also had the car stop completely when the car in front of me stopped, which is partly why I was so surprised.
> 
> I really, really don't think my foot touched the accelerator on the way to the brake, but I suppose it's possible.


Whatever - I'm just glad you're ok. The car is just a thing, can be fixed. While I say I've had some luck with having the car stop itself in panic situations, there have also been times when I've taken over. And there's certainly enough horror stories not unlike your own that the system can't be trusted to be able to handle all situations.


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## DiscTech Wizard

I had the same thing happened on AP. I was able to react fast enough to change to the right lane. Had to fight the AP, argh, glad that I did not hit the car in front of me. Had the whole family in the card too.


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## jdcollins5

I have had AEB activate when the car in front of me slowed suddenly when I was distracted. I instinctively hit the brakes and was able to stop in time. If AEB had not activated first I doubt I could have stopped in time.

Everyone needs to read the section from the manual that @Frully posted to be sure that you understand that the car currently is not designed to stop completely to avoid a collision, but to limit the severity of the collision.


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## JasonF

jdcollins5 said:


> Everyone needs to read the section from the manual that @Frully posted to be sure that you understand that the car currently is not designed to stop completely to avoid a collision, but to limit the severity of the collision.


That shouldn't be your last line of defense. _Increasing your follow distance_ should be. There is a mental lag after realizing something is wrong when you're not fully controlling the car - it can happen even while on plain old cruise control. Your follow distance should be adjusted accordingly.

In Florida people tend to drive too close, so on higher-speed roads I tend to leave a lot of extra distance in front. That way if the car in front stops very suddenly, and there's a car too close behind, I can give them a lot of extra time to react as I more comfortably close the distance.


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## Andy Kaplan

After reading these replies (and those on another forum), I think there is confusion between two different systems (at least I'm confused.)

On the one hand, there is the automatic emergency braking. I think that system works when you're driving (under your own control) and the car thinks you're going to hit something. In that case, it does some automatic braking to limit the severity of the crash.

On the other hand -- and what happened to me -- is that autopilot was driving and didn't handle the short stop in front of me on the highway correctly -- just didn't slow down anywhere near fast enough. The two systems might interact, but autopilot -- in every other situation -- maintains a set distance between me and the car in front of me, and (usually) stops if/when they stop and accelerates if there is room. In this case, it just didn't try to stop fast enough. Perhaps this is a design "feature" to prevent emergency stops by autopilot when it is phantom braking and causing more rear end accidents, I don't know. 

But I think there is a difference between the two that matters.


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## M3OC Rules

Andy Kaplan said:


> This morning, I was on autopilot on the highway in clear, sunny weather (and I was paying attention).
> Suddenly, the car in front of me stopped short -- and autopilot didn't slow down fast enough. Once I realized that, I jammed on the brakes, but too late -- I hit the car in front of me.
> Really confused about this. Presumably, the car is supposed to react faster than I can. I think that if I had been driving and slammed on the brakes, I might have avoided the accident.
> Really just an FYI to the group. Not only should you always pay attention when using autopilot, we need to realize that it may not avoid accidents as well as (I) thought.


Sorry to hear about your accident. In some situations, it does close in too fast to stopped cars sometimes. Can you provide some details of the situation? What was your speed? What was your follow distance and how fast did the other car slow down? Was the car in front of you in that lane for a long time?
If you really think you were on autopilot you could ask Tesla if they will tell you what happened. Not sure they do that but I think they might review every accident on autopilot automatically.


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## JWardell

I'm curious from an engineering perspective what exactly happened here. I would presume autopilot would have stopped completely just like it does in traffic.
Of course If the car in front somehow stops faster than your can is physically able to...by hitting something, for example, then there is nothing that can be done.
Do you think there is any chance you might have pressed the accelerator? That may override.
Otherwise I'm very curious what happened here. Video may help, or any other details you can remember. Of course it's difficult to remember details in a stressful event.
Glad you are OK and hopefully the car can be repaired and back to you quickly.


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## NR4P

Sorry to hear about your accident and glad everyone is OK.
I seem to recall somewhere, was it an earnings call or Model Y announcement one of Tesla's lead engineers made a statement that when an accident occurs in AP, he gets the videos to review, automatically.

Now you may find it impossible to see it but perhaps some pressure on Tesla could at least get someone to acknowledge the incident. 

This is the second known AP crash in a month, the last one in Russia very recently.


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## jdcollins5

Andy Kaplan said:


> After reading these replies (and those on another forum), I think there is confusion between two different systems (at least I'm confused.)
> 
> On the one hand, there is the automatic emergency braking. I think that system works when you're driving (under your own control) and the car thinks you're going to hit something. In that case, it does some automatic braking to limit the severity of the crash.
> 
> On the other hand -- and what happened to me -- is that autopilot was driving and didn't handle the short stop in front of me on the highway correctly -- just didn't slow down anywhere near fast enough. The two systems might interact, but autopilot -- in every other situation -- maintains a set distance between me and the car in front of me, and (usually) stops if/when they stop and accelerates if there is room. In this case, it just didn't try to stop fast enough. Perhaps this is a design "feature" to prevent emergency stops by autopilot when it is phantom braking and causing more rear end accidents, I don't know.
> 
> But I think there is a difference between the two that matters.


I replied to your thread on the Tesla Model 3 forum and will reply here also. In my experiences, when I am using TACC and a car in front of me has stopped or slowed down suddenly, there is no way that the radar distance controller could have reacted fast enough to prevent a collision. In my cases, I received a Forward Collision Warning and then Automatic Emergency Braking activated until I instinctively hit the brakes.

I can understand your confusion, but I do not understand why you did not get a FCW and AEB. From my experience this should work with or without AP (TACC).


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## SR22pilot

JWardell said:


> I'm curious from an engineering perspective what exactly happened here. I would presume autopilot would have stopped completely just like it does in traffic.
> Of course If the car in front somehow stops faster than your can is physically able to...by hitting something, for example, then there is nothing that can be done.
> Do you think there is any chance you might have pressed the accelerator? That may override.
> Otherwise I'm very curious what happened here. Video may help, or any other details you can remember. Of course it's difficult to remember details in a stressful event.
> Glad you are OK and hopefully the car can be repaired and back to you quickly.


Isn't it quite possible that adaptive cruise control has a max normal braking and that after that it becomes AEB with all of the limitations stated earlier? Because of the dangers of having the car rapidly brake for no reason (phantom braking) I suspect automatic braking has limitations as to the amount of braking. Yes, adaptive cruise control will fully stop the car but I suspect it is prevented from doing it in a slam on the brakes way.


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## M3OC Rules

Andy Kaplan said:


> After reading these replies (and those on another forum), I think there is confusion between two different systems (at least I'm confused.)
> 
> On the one hand, there is the automatic emergency braking. I think that system works when you're driving (under your own control) and the car thinks you're going to hit something. In that case, it does some automatic braking to limit the severity of the crash.
> 
> On the other hand -- and what happened to me -- is that autopilot was driving and didn't handle the short stop in front of me on the highway correctly -- just didn't slow down anywhere near fast enough. The two systems might interact, but autopilot -- in every other situation -- maintains a set distance between me and the car in front of me, and (usually) stops if/when they stop and accelerates if there is room. In this case, it just didn't try to stop fast enough. Perhaps this is a design "feature" to prevent emergency stops by autopilot when it is phantom braking and causing more rear end accidents, I don't know.
> 
> But I think there is a difference between the two that matters.


Yes. Automatic emergency braking isn't something you should rely on. It helps in some situations when the driver fails. It may stop and prevent an accident, it may slow down and reduce the severity of an accident, or it may do neither.

When you're on Autopilot you could also say it's not something you should rely on. But it is designed to work in stop and go traffic for instance. It's just not guaranteed to work which could be confusing. I've used autopilot a ton in my 14,000 miles and I can think of one instance where I was on autopilot on the freeway and I don't think it would have stopped in time and I was surprised.

Not sure how much the two systems share code but they definitely share sensors. There is probably is a high correlation between AEB failing when Autopilots fails.


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## M3OC Rules

jdcollins5 said:


> I can understand your confusion, but I do not understand why you did not get a FCW and AEB


We don't know all the details in this case but they don't work 100% of the time. They don't work 100% of the time.


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## JasonF

JWardell said:


> I'm curious from an engineering perspective what exactly happened here. I would presume autopilot would have stopped completely just like it does in traffic.


In my opinion, it's related to some kind of Autopilot feature that tries to "smooth out" violent stops and starts by braking or accelerating a little late. Rather than waiting too long to stop, I think just before that incident, the car ahead slowed, and then pulled away quickly, and Autopilot was accelerating to catch up to maintain its follow distance. When the car ahead suddenly stopped, the AP car _hadn't reached its optimal follow distance yet_, so it was going to brake very late (except the driver interrupted it by braking first).

If that sounds right, it could be more than just an Autopilot failure. Just about all traffic-aware cruise could potentially have the same issue, because they all have the same "smooth out" features to avoid jerky and violent driving.

Because that theory is related to AP failing due to trying to close and maintain its follow distance, the appropriate workaround would be to increase the follow distance.


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## Andy Kaplan

I had a chance to check the videos -- unfortunately, no clips from the accident. I didn't have the presence of mind to hit the "save" button quickly enough...
...I'm going to try to contact Tesla to see if they can tell me what happened from the logs. The more I think about it, the less it makes sense that I had the crash -- autopilot stops in just about every other circumstance, why not this one? All the cars in front of me and behind me were able to stop, all driven by slow humans....

(For those that asked, everything happened very quickly, but as I recall: car in front jammed on brakes; autopilot started to slow down the car; and then just about simultaneously, I slammed on the brakes, got the forward crash warning and AEB may have also kicked in. Re-examining the damage this morning, it's less bad than I thought -- so I'm now going to estimate a crash at around 20 - 25 miles an hour, though I'm no expert. Based on the damage to the other car (just about none) and the damage to mine (much more and higher up), I'm pretty sure the nose was down due to the extreme attempt at braking. I'll ask the body shop for their opinion.)


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## JWardell

Andy Kaplan said:


> I had a chance to check the videos -- unfortunately, no clips from the accident. I didn't have the presence of mind to hit the "save" button quickly enough...
> ...I'm going to try to contact Tesla to see if they can tell me what happened from the logs. The more I think about it, the less it makes sense that I had the crash -- autopilot stops in just about every other circumstance, why not this one? All the cars in front of me and behind me were able to stop, all driven by slow humans....
> 
> (For those that asked, everything happened very quickly, but as I recall: car in front jammed on brakes; autopilot started to slow down the car; and then just about simultaneously, I slammed on the brakes, got the forward crash warning and AEB may have also kicked in. Re-examining the damage this morning, it's less bad than I thought -- so I'm now going to estimate a crash at around 20 - 25 miles an hour, though I'm no expert. Based on the damage to the other car (just about none) and the damage to mine (much more and higher up), I'm pretty sure the nose was down due to the extreme attempt at braking. I'll ask the body shop for their opinion.)


Even if you didn't save the videos, there is a good chance the video data isn't gone if it hasn't been recorded over. There are utilities that can restore deleted files that might find it.

Also, did your airbags trigger? If so the car saved an EDR report that can also be pulled with lots of pertinent info.

But it does sound with your latest info that there just wasn't enough physical time, if AEB did sound and pre-load the brakes, and you also pressed the pedal. And yes, especially if your hood dove below their bumper. May have just been physics after all.


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## Nom

Put me in the camp of expecting (I believe reasonably) that the car would try to fully stop. 

The discussions above that it would only slow and not try to stop just seems like a rationalization trying to defend Tesla.

You all seem to know this stuff better than me but some of this is more like common sense to me. The car stops itself in normal traffic. It should try to stop in this situation.

Maybe not enough room - fine. But the idea of letting off the brake is weird.


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## jdcollins5

Nom said:


> Put me in the camp of expecting (I believe reasonably) that the car would try to fully stop.
> 
> The discussions above that it would only slow and not try to stop just seems like a rationalization trying to defend Tesla.
> 
> You all seem to know this stuff better than me but some of this is more like common sense to me. The car stops itself in normal traffic. It should try to stop in this situation.
> 
> Maybe not enough room - fine. But the idea of letting off the brake is weird.


Not defending Tesla. Try reading the Owner's Manual pages 90-91 on Collision Avoidance.


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## M3OC Rules

Nom said:


> Put me in the camp of expecting (I believe reasonably) that the car would try to fully stop.
> The discussions above that it would only slow and not try to stop just seems like a rationalization trying to defend Tesla.
> You all seem to know this stuff better than me but some of this is more like common sense to me. The car stops itself in normal traffic. It should try to stop in this situation.
> Maybe not enough room - fine. But the idea of letting off the brake is weird.


Getting these things to work is harder than you think. Right now they are just assist. They may help prevent accidents or reduce severity but they don't work 100% of the time. It's hard to know what happened here without a lot more information. Its sort of interesting to think that Tesla probably has all that information though and probably will figure out what happened. Hopefully, they are using that info wisely.


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## garsh

Nom said:


> The discussions above that it would only slow and not try to stop just seems like a rationalization trying to defend Tesla.


I don't think people are "rationalizing" or "defending". They're just putting out theories about what _may_ have happened. We weren't there, so we don't know for sure. But there are several possible explanations.

Driver lightly tapped the brake. This will turn off autopilot.
Driver lightly tapped the accelerator. This will override autopilot until the driver stops doing so, at which point it may have been too late.
Perhaps the cars in front simply decelerated too quickly to avoid the accident.
Or, like in this video, this was a case of autopilot failing in a situation that it successfully handles 99% of the time.
Autopilot can be wonderful, but it's still considered "BETA", and Tesla still warns owners to pay attention and be ready to take over at all times when you activate the feature. Regardless of the reason for the failure, this incident should highlight to everybody that it's not an infallible system, and to not trust it to avoid an accident.


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## mswlogo

MelindaV said:


> the "recent" video will continue recording the p[rior 60 minutes, so if this has been more than an hour ago, it likely has been over written already.


If all he did was hit the "save" button that only saves previous 10 minutes. Only way to get the last hour is to pull the stick. Sounds like it's gone.


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## mswlogo

SR22pilot said:


> Isn't it quite possible that adaptive cruise control has a max normal braking and that after that it becomes AEB with all of the limitations stated earlier? Because of the dangers of having the car rapidly brake for no reason (phantom braking) I suspect automatic braking has limitations as to the amount of braking. Yes, adaptive cruise control will fully stop the car but I suspect it is prevented from doing it in a slam on the brakes way.


I guess that's the question. Will ACC stop more aggressively than AEB. It makes some sense that it wouldn't.

You kind of think that ACC can see the deceleration of the car quicker than you can and do better.

One thing I love on my Jeep is that once you do touch the brake in emergency situations, it does not hand control over to you. It AMPLIFIES the braking and works together, because it's extremely common people underestimate how hard they need to brake on emergency stops (or brake late). So if you do nothing it will do similar to Model 3 and do limited slow down. But as soon as you touch the brakes and it sees you are approaching an obstacle it will slam on the brakes because you are basically confirming there is a problem that it also sees and it jumps in helps you stop "better". It also sets the brakes up (puts them against the rotors) if it sees a problem before braking is applied so that it can brake a fraction of a second sooner.


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## SR22pilot

Nom said:


> Put me in the camp of expecting (I believe reasonably) that the car would try to fully stop.
> 
> The discussions above that it would only slow and not try to stop just seems like a rationalization trying to defend Tesla.
> 
> You all seem to know this stuff better than me but some of this is more like common sense to me. The car stops itself in normal traffic. It should try to stop in this situation.
> 
> Maybe not enough room - fine. But the idea of letting off the brake is weird.


I am coming form a couple of standpoints. First, several manufacturers mentions that AEB won't prevent collisions but only mitigate them. This isn't just a Tesla issue. Secondly, some mention that they will only brake with a partial level since false full force braking could cause accidents. Go read the posts on this forum on phantom braking. Now imaging you are in traffic and the car unexpectedly applies maximum braking for a phantom event. In a perfect world there would be no phantom braking but we aren't there yet. From my experience we aren't close. I may be a Tesla fanboy but that isn't driving my comments. I am just guessing what the engineers probably did and it is somewhat backed up by what is stated in the manual. I am also basing my opinion on what other manufacturers have said about their systems.


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## garsh

mswlogo said:


> One thing I love on my Jeep is that once you do touch the brake in emergency situations, it does not hand control over to you. It AMPLIFIES the braking and works together, because it's extremely common people underestimate how hard they need to brake on emergency stops (or brake late). So if you do nothing it will do similar to Model 3 and do limited slow down. But as soon as you touch the brakes and* it sees you are approaching an obstacle*...


The bolded part is key.

In my Leaf, if I were to hit the brakes hard, but then realize that I didn't have to slow down after all, the Leaf would continue panic-braking until almost a complete stop after I take my foot off the brake. I'm surprised that I was never rear-ended when it would do that. I guess the thought was that a driver's foot probably slipped off the brake pedal during a panic stop. I hated that feature.


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## Andy Kaplan

Definitely confusing -- and, as many posters have mentioned, it's hard to know what the correct design parameters are, between mitigating "phantom braking" to avoiding accidents. I don't think it's a matter of too little space because all the cars in front panicked stopped without an accident (it wasn't just the car I hit) as did all the cars behind...

I'd like to reach Tesla to have them look at the logs and let me know what was supposed to happen. Anyone know the best way to get Tesla to take a look at this? I'd have to imagine Autopilot crashes would be of interest....


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## M3OC Rules

mswlogo said:


> One thing I love on my Jeep is that once you do touch the brake in emergency situations, it does not hand control over to you. It AMPLIFIES the braking and works together, because it's extremely common people underestimate how hard they need to brake on emergency stops (or brake late). So if you do nothing it will do similar to Model 3 and do limited slow down. But as soon as you touch the brakes and it sees you are approaching an obstacle it will slam on the brakes because you are basically confirming there is a problem that it also sees and it jumps in helps you stop "better". It also sets the brakes up (puts them against the rotors) if it sees a problem before braking is applied so that it can brake a fraction of a second sooner.


I think many manufacturers do this or have done this especially before the cars started braking on their own. (Wikipedia) I think if the car is braking then the need to amplify is lessened. I saw one that specifically said the car could apply maximum braking force on its own. I'm not sure about the situation of amplified braking on a Tesla. It does say that the AEB stops if you push on the brake and then stop pushing on the brake which implies it stays on when you have your foot on the brake after its started.


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## SR22pilot

Interesting AEB tests including on Model S.

https://www.caranddriver.com/featur...es-automatic-braking-system-tested-explained/


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## SR22pilot

Older Mercedes autos would only apply 60% max. Newer ones will go with max braking but later in the event so it may not prevent a collision.

From an Infiniti owner's manual:

_The FEB system operates at speeds above approximately 3 MPH (5 km/h).

If a risk of a forward collision is detected, the FEB system will provide the first warning to the driver by flashing the driver assist system forward indicator (orange) and the vehicle ahead detection indicator (orange), and providing an audible warning. In addition, the FEB system pushes the accelerator pedal up. If the driver releases the accelerator pedal, then the system applies *partial *braking.

If the driver applies the brakes quickly and forcefully after the warning, and the FEB system detects that there is still the possibility of a forward collision, the system will automatically increase the braking force.

If a forward collision is imminent and the driver does not take action, the FEB system issues the second visual (red) and audible warning and automatically *applies harder braking.* If the driver is handling the steering wheel, accelerating or braking, the FEB system will function later or will not function.

The automatic braking will cease under the following conditions:

. When the steering wheel is turned as far as necessary to avoid a collision.
. When the accelerator pedal is depressed.
. When there is no longer a vehicle detected ahead.

If the FEB system has stopped the vehicle, the vehicle will remain at a standstill for approximately 2 seconds before the brakes are released._

_The radar sensor has some performance limitations. If a stationary vehicle is in the vehicle's path, the FEB system will not function when the vehicle is driven at speeds over approximately 45 MPH (70 km/h)._


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## mswlogo

M3OC Rules said:


> I think many manufacturers do this or have done this especially before the cars started braking on their own. (Wikipedia) I think if the car is braking then the need to amplify is lessened. I saw one that specifically said the car could apply maximum braking force on its own. I'm not sure about the situation of amplified braking on a Tesla. It does say that the AEB stops if you push on the brake and then stop pushing on the brake which implies it stays on when you have your foot on the brake after its started.


I didn't see anything about "amplifying" user input in your Wikipedia reference. I think the concept works great. It only makes sense on cars that could brake on their own and mine will. But if you jump in it tries to work together.

Where the Tesla seems to lean more hands off if you touch throttle or brake during AEB. And I suspect that's what happened to OP.

I sometimes brake less in emergencies when I don't have time to check behind me and try to use the minimum braking to stop in time. But in the split second it's really hard to judge accurately for something you rarely do. But I find it instinctive to not fully slam on the brakes. But the car can calculate exactly what's needed and it works great.

It sounds like the MB does something similar to the Jeep.

I sure wish the Tesla would factor in what's behind it with the camera.


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## Andy Kaplan

Some updates:
1) I'm scanning the drive I used for Sentry footage. I'm trying to recover the video footage of the accident. Will post if I'm successful.

2) I've been trying to see if someone at Tesla would pull my logs to tell me what happened. Essentially, I think it's one of a few possibilities: 1) physics of the situation made it impossible to slow down fast enough (I doubt this one because no one else crashed, either in the group of stopped cars in front of me or the cars behind me); 2) this is intentional design -- slow the car less than a panic stop to prevent getting rear-ended in a potential phantom breaking situation; 3) this is a bug; 4) some kind of operator error.

But after chatting with Tesla, they won't pull logs without a court order and directed me to the pages that tell you how to connect up a cable to the electronic data record and make my own report...but the cable is very expensive and the "simple" procedure involves taking apart a bunch of the car....I told them I'm not trying to place any kind of blame, I know it's beta software, etc. but they wouldn't do it...

Any thoughts on this?


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## M3OC Rules

mswlogo said:


> I didn't see anything about "amplifying" user input in your Wikipedia reference. I think the concept works great. It only makes sense on cars that could brake on their own and mine will. But if you jump in it tries to work together.
> Where the Tesla seems to lean more hands off if you touch throttle or brake during AEB. And I suspect that's what happened to OP.
> I sometimes brake less in emergencies when I don't have time to check behind me and try to use the minimum braking to stop in time. But in the split second it's really hard to judge accurately for something you rarely do. But I find it instinctive to not fully slam on the brakes. But the car can calculate exactly what's needed and it works great.
> It sounds like the MB does something similar to the Jeep.
> I sure wish the Tesla would factor in what's behind it with the camera.


I believe they are calling what you're talking about as "amplifying" is known as brake assist. Here is another reference.

I guess I'm not understanding where you're getting the idea that Tesla is hands-off if you touch the brake. That doesn't make sense and isn't consistent with what the manual says. I don't think you can come to that conclusion from the OP.


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## JWardell

Andy Kaplan said:


> Some updates:
> 1) I'm scanning the drive I used for Sentry footage. I'm trying to recover the video footage of the accident. Will post if I'm successful.
> 
> 2) I've been trying to see if someone at Tesla would pull my logs to tell me what happened. Essentially, I think it's one of a few possibilities: 1) physics of the situation made it impossible to slow down fast enough (I doubt this one because no one else crashed, either in the group of stopped cars in front of me or the cars behind me); 2) this is intentional design -- slow the car less than a panic stop to prevent getting rear-ended in a potential phantom breaking situation; 3) this is a bug; 4) some kind of operator error.
> 
> But after chatting with Tesla, they won't pull logs without a court order and directed me to the pages that tell you how to connect up a cable to the electronic data record and make my own report...but the cable is very expensive and the "simple" procedure involves taking apart a bunch of the car....I told them I'm not trying to place any kind of blame, I know it's beta software, etc. but they wouldn't do it...
> 
> Any thoughts on this?


As I mentioned before, I believe an EDR is only recorded if air bags were triggered. But it's not too difficult to pull yourself.
I posted my process here:
https://teslaownersonline.com/threa...ecorder-access-by-can.6175/page-2#post-199280


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## Nom

The car and driver article shows the Model S stopped. Not in all conditions but in several non high speed conditions it avoided impact. This is what I would expect. Won’t be perfect, I know. 

It is interesting to learn that it fails at higher speeds. I recognize that others are saying this is the idea of reducing speed but not getting to a full stop. Outside the parameters.

Interesting and good to know.


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## Andy Kaplan

Thanks to the great suggestion by @JWardell, I used disk recovery software to find the video of the accident....it there a safe way to post?

I really think it shows autopilot just not slowing down in time....even though it looks like it could have/should have.....really weird....and I'm as certain as I can be that I didn't hit the brake or otherwise hit any controls until the last panic stop.


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## iChris93

Andy Kaplan said:


> .it there a safe way to post?


You can upload to YouTube and then copy the link here. The site will automatically embed the video.


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## LakeWorthB

Andy Kaplan said:


> Thanks to the great suggestion by @JWardell, I used disk recovery software to find the video of the accident....it there a safe way to post?
> 
> I really think it shows autopilot just not slowing down in time....even though it looks like it could have/should have.....really weird....and I'm as certain as I can be that I didn't hit the brake or otherwise hit any controls until the last panic stop.


Post it yet?


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## Andy Kaplan

Here's an update:

First, here's a link to the video. I think it show autopilot working fine -- then just not stopping. Perhaps the car in front accelerated first before jamming on the brakes?






Second, had the car appraised. For a crash where I'd estimate the impact speed at < 25 mph and no air bags, it's $10k worth of damage. Yikes.

Third...maybe the worst part, something I didn't really know...it can take from two to eight weeks to get the parts! I know Tesla is focusing on manufacturing new cars, but weeks and weeks for parts is crazy....


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## JWardell

Andy Kaplan said:


> Here's an update:
> 
> First, here's a link to the video. I think it show autopilot working fine -- then just not stopping. Perhaps the car in front accelerated first before jamming on the brakes?
> 
> 
> 
> 
> 
> 
> Second, had the car appraised. For a crash where I'd estimate the impact speed at < 25 mph and no air bags, it's $10k worth of damage. Yikes.
> 
> Third...maybe the worst part, something I didn't really know...it can take from two to eight weeks to get the parts! I know Tesla is focusing on manufacturing new cars, but weeks and weeks for parts is crazy....


Wow. Certainly seems like AP should have handled that. Did the car in front of the car in front of you hit something or just jerk to the side? Radar should have picked up that abrupt stop, and certainly plenty of space to stop before you hit anything.
Doesn't look like much damage to the MINI, looks to me like you only hit ~5mph. Was your damage only to the front bumper? Have you looked under to see if the beam is crushed? If not $10k is super high for that. If hood and fenders need replacement and paint, then I suppose that is about right.

On second view it looks like the MINI illuminates a second set of brake lights which should occur only when extreme braking, so maybe this is all occurring faster and harder than it appears.

My only guess though is all those overhead bridges and gantries often confuse autopilot and cause phantom braking issues, and so maps are marked to ignore stationary stings in these areas, maybe that has something to do with the unexpected response.


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## Gabzqc

Andy Kaplan said:


> Here's an update:
> 
> First, here's a link to the video. I think it show autopilot working fine -- then just not stopping. Perhaps the car in front accelerated first before jamming on the brakes?
> 
> 
> 
> 
> 
> 
> Second, had the car appraised. For a crash where I'd estimate the impact speed at < 25 mph and no air bags, it's $10k worth of damage. Yikes.
> 
> Third...maybe the worst part, something I didn't really know...it can take from two to eight weeks to get the parts! I know Tesla is focusing on manufacturing new cars, but weeks and weeks for parts is crazy....


Good to see the video. What's your follow distance set to? Is there any chance you cancelled TACC just before impact?


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## mswlogo

JWardell said:


> Wow. Certainly seems like AP should have handled that. Did the car in front of the car in front of you hit something or just jerk to the side? Radar should have picked up that abrupt stop, and certainly plenty of space to stop before you hit anything.
> Doesn't look like much damage to the MINI, looks to me like you only hit ~5mph. Was your damage only to the front bumper? Have you looked under to see if the beam is crushed? If not $10k is super high for that. If hood and fenders need replacement and paint, then I suppose that is about right.
> 
> On second view it looks like the MINI illuminates a second set of brake lights which should occur only when extreme braking, so maybe this is all occurring faster and harder than it appears.
> 
> My only guess though is all those overhead bridges and gantries often confuse autopilot and cause phantom braking issues, and so maps are marked to ignore stationary stings in these areas, maybe that has something to do with the unexpected response.


Do you know fa fact that stationary objects are marked to be ignored. I find that very hard to believe and would be very dangerous.

I agree, TACC should have handled that.


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## Andy Kaplan

Follow distance was set to 1. I was on autopilot until a couple of seconds before the crash -- when I realized I wasn't going to stop on time -- and I jammed on the brakes.

The estimate calls for replacing the bumper and grill with all the mounting brackets, the front lamps, the hood and frunk (apparently slightly misshapen) the fender, one of the home link mods, and I think the radar. Apparently, everything got pushed back about 1.5".

The other car had a little blemish on her bumper.

Here's what the front of my car looked like:


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## Andy Kaplan

Oh -- and I don't think the car in front of the car I contacted hit anything -- I think they *almost* hit something so jammed on the brakes and went sideways a bit to avoid the accident.

That's what's so surprising, to me -- none of the cars in front of me got into an accident, nor did the cars behind me. Just me.


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## JWardell

Andy Kaplan said:


> Follow distance was set to 1. I was on autopilot until a couple of seconds before the crash -- when I realized I wasn't going to stop on time -- and I jammed on the brakes.
> 
> The estimate calls for replacing the bumper and grill with all the mounting brackets, the front lamps, the hood and frunk (apparently slightly misshapen) the fender, one of the home link mods, and I think the radar. Apparently, everything got pushed back about 1.5".
> 
> The other car had a little blemish on her bumper.
> 
> Here's what the front of my car looked like:
> 
> View attachment 28822


Do you get any errors on your screen about radar or parking sensors? That actually looks fairly light, I'm wondering if you took the bumper off and massaged everything, pushed out the dent, and buffed away the scratches, that everything would look decent. Does the hood latch?



mswlogo said:


> Do you know fa fact that stationary objects are marked to be ignored. I find that very hard to believe and would be very dangerous.
> 
> I agree, TACC should have handled that.


All TACC systems are programmed to be more likely to ignore stationary objects when traveling at highway speeds (>45mph?). Tesla's HD maps have been know to mark areas of frequent phantom breaking because of overhead signs and bridges and further reduce chances of erroneously braking for them. I'm curious if that had a part in this. Also don't really know the driving speed or speed of impact, I'm just speculating all over the place here.

Driving in stop (fast) and go (fast) traffic with following distance 1 is probably how I most use autopilot. It should handle this situation very well. That's why I'm curious.


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## M3OC Rules

Andy Kaplan said:


> Here's an update:
> First, here's a link to the video. I think it show autopilot working fine -- then just not stopping. Perhaps the car in front accelerated first before jamming on the brakes?
> Second, had the car appraised. For a crash where I'd estimate the impact speed at < 25 mph and no air bags, it's $10k worth of damage. Yikes.
> Third...maybe the worst part, something I didn't really know...it can take from two to eight weeks to get the parts! I know Tesla is focusing on manufacturing new cars, but weeks and weeks for parts is crazy....


Thanks for posting that. I agree I would have expected it to handle that situation. Hopefully, you get your car fixed soon.


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## Andy Kaplan

Agreed! That's how I've been using it, I'm sure it's worked in similar situations in the past -- that's why it was so surprising.

Yes, I get error messages about not being able to use autopilot or "convenience features".


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## M3OC Rules

JWardell said:


> Tesla's HD maps have been know to mark areas of frequent phantom breaking because of overhead signs and bridges and further reduce chances of erroneously braking for them.


Wow. I didn't know about this. That seems like the worst band-aid ever. It seems like they have to rip quite a few band-aids off before they get to level 4. Lots involving bad map data. Maps are only good for picking a route. Not the speed limit. Not what lane to be in. And definitely not for no brake zones.

I wonder if it just didn't react fast enough. Autopilot does seem slow to react to things sometimes. Like if a car crosses your path on a side street it takes a second to start slowing and then it doesn't stop slowing until the car is well by. (I know you're not supposed to use it there...) It was reacting to the slowing speed of the car but then it didn't react quickly when the car slammed on its brakes. It looks like about 2 seconds from when the car in front emergency braked to when the collision took place. If it took a second to react, that might have been about when Andy took over which was too late.


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## RD88

Watching your dash cam footage and wondering if anyone else thinks the Mini looks like it was driving too close and not paying attention to the traffic?
If they'd have left a more sensible gap they and you (or AP) would have had more time to react.


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## gary in NY

After reviewing the video, the incident seems to have been a close call for a few of the vehicles ahead. There is a pickup four cars ahead that swerves sharply onto the left shoulder and the second car ahead swerves less sharply to the right. These seem like moves intended to avoid a collision. The pickup pulls back into the travel lane once the vehicles start moving again. 

I wonder if the car detected any of this sudden motion. If it did, was it able to interpret the situation, or was it confused by it. I have to agree that it should have handled this without incident. I would have been perfectly at ease using TACC or AP in such a situation, as this is where it can be most helpful.


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## thevenun

Andy Kaplan said:


> This morning, I was on autopilot on the highway in clear, sunny weather (and I was paying attention).
> 
> Suddenly, the car in front of me stopped short -- and autopilot didn't slow down fast enough. Once I realized that, I jammed on the brakes, but too late -- I hit the car in front of me.
> 
> Really confused about this. Presumably, the car is supposed to react faster than I can. I think that if I had been driving and slammed on the brakes, I might have avoided the accident.
> 
> Really just an FYI to the group. Not only should you always pay attention when using autopilot, we need to realize that it may not avoid accidents as well as (I) thought.


I almost had the car not notify the other day and the forward collision detection was not set to early, so I set it to early, might have changed after updates?


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## ElectricBiker

wow, if not gas pedal hit,or disengage of AP, it surely looks like AP should have avoided this. Like people have said, AP can slow all the way down to 0mph in traffic, so no difference here. I just can't tell if the car ahead had a hard stop(close to skidding) one that was too much for AP to stop to standstill, or if it was just an abrupt stop which AP should catch. I normally have my AP on 3 car follow distance. Never had any close issues like this so far. Downside is when you're at 3 or 4 car length setting, everybody tries to jump in front of the little gap ahead of you and the car in front


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## Andy Kaplan

Subsequent to the accident, I now use AP at 4 and pay *much* closer attention.

(I now suspect that AP might have been confused by the sun and series of overpasses on that stretch of road -- they had been working on trying to address the "phantom braking" issues and I wonder if that might be the cause...

...pure speculation, of course....


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## kataleen

Andy Kaplan said:


> The other car had a little blemish on her bumper.


Don't be fooled by that. I've seen a case with my own eyes where a car was rear-ended, the outside had almost zero traces (very minor scratch barely visible) and behind, the crash bar completely bent out of shape. The bumpers are very strong and flexible and don't shatter anymore like they used to. Also if the impactor is smooth, it won't leave any marks, but all the damage will be behind the bumper. Unfortunately that's what is more expensive to repair many times.



ElectricBiker said:


> Downside is when you're at 3 or 4 car length setting, everybody tries to jump in front of the little gap ahead of you and the car in front


I always keep it on 7 and have absolutely no problem with other cars using that gap. I am more than happy to let them use it and at the same time happy that I don't get rocks all over my windshield, let alone risky situations like the OP had the misfortune to run into. It's surprising how rare other cars try to "cut" into that gap but maybe it's not the same everywhere.


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## Mr. Spacely

Andy Kaplan said:


> Subsequent to the accident, I now use AP at 4 and pay *much* closer attention. (I now suspect that AP might have been confused by the sun and series of overpasses on that stretch of road -- they had been working on trying to address the "phantom braking" issues and I wonder if that might be the cause... pure speculation, of course....


...or your right foot was gently resting on the accelerator


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## Drhalo

AEB failed to act in my model 3, at under 35 MPH and my car was involved in an accident. I don't trust it at all. Seems very flaky. My feeling is that it should be able to bring the car to a complete stop. It is well documented that the Teslas have a problem with stopped vehicles in its path.


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## Dogwhistle

Yet another concern with the car able to achieve “full self-driving”. Will it get another algorithm for braking before we trust it enough to ride in the back seat? Will it be able to react to sudden stops like that, or just accept a slow-speed crash? So many corner cases that have to be solved.


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## JasonF

Dogwhistle said:


> Yet another concern with the car able to achieve "full self-driving". Will it get another algorithm for braking before we trust it enough to ride in the back seat? Will it be able to react to sudden stops like that, or just accept a slow-speed crash? So many corner cases that have to be solved.


There will have to be - because if self-drive can't operate without a driver capable of taking over being aboard, there is great danger of regulatory authorities across the world from banishing it from the roads. And because regulations are hard to overturn, that would set back the entire concept of self-driving cars by decades. There is too much at stake to be cutting corners.


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## SR22pilot

Drhalo said:


> AEB failed to act in my model 3, at under 35 MPH and my car was involved in an accident. I don't trust it at all. Seems very flaky. My feeling is that it should be able to bring the car to a complete stop. It is well documented that the Teslas have a problem with stopped vehicles in its path.


ALL active cruise control systems have a problem with stopped cars. Well, all that are in production cars. LIDAR can avoid this issue. The worst case is a stopped car that gets uncovered by a moving vehicle changing lanes. To radar, the stopped car looks like a road that is rising. For Tesla the solution will probably be more reliance on camera input.


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## radlaw

SR22pilot said:


> For Tesla the solution will probably be more reliance on camera input.


The solution is for the driver to pay attention to what he/her are doing, and NOT rely on autopilot, cameras and sensors. I'm old school and look at the road when I'm driving.


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## JasonF

Humans can't "see" stopped vehicles either. That's why so many human-driven cars crash into vehicles stopped on the side of the road. So we're better at it than software, but only because we understand context - something software is not good at.


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## Drhalo

My car failed to activate the emergency braking and was only going 12 MPH and the damage to my bumper was substantially less than yours. My bill came to 17K and was out of commission for 2 months.


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## radlaw

JasonF said:


> Humans can't "see" stopped vehicles either. That's why so many human-driven cars crash into vehicles stopped on the side of the road. So we're better at it than software, but only because we understand context - something software is not good at.


I can see stopped vehicles. Distractions are the main cause of accidents. Pay attention to the driving. The software should be used in addition to paying attention; not in place of it.


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## iChris93

Drhalo said:


> 17K


Woah! What all needed to be replaced?


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## FRC

iChris93 said:


> Woah! What all needed to be replaced?


There must have been substantial unseen damage. Tesla replaced my bumper cover and hood after an accident for $1050. I was out of commission for 2 days.


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## sduck

If that was 17K you need to take better pictures because you left a lot out. Bumper replacement is 4K tops, usually cheaper.


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## SR22pilot

radlaw said:


> The solution is for the driver to pay attention to what he/her are doing, and NOT rely on autopilot, cameras and sensors. I'm old school and look at the road when I'm driving.


Good point. I was addressing correcting detection failures by the warning systems.


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## Drhalo

iChris93 said:


> Woah! What all needed to be replaced?


I'm convinced there was a lot of extras they added. Radiator support, hood, both lights, mirror, paint protection film.


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## M3OC Rules

Drhalo said:


> AEB failed to act in my model 3, at under 35 MPH and my car was involved in an accident. I don't trust it at all. Seems very flaky. My feeling is that it should be able to bring the car to a complete stop. It is well documented that the Teslas have a problem with stopped vehicles in its path.


You're not supposed to trust it. There is no car you can trust to stop on it's own.


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## Mr. Spacely

Drhalo said:


> AEB failed to act in my model 3, at under 35 MPH and my car was involved in an accident. I don't trust it at all. Seems very flaky. My feeling is that it should be able to bring the car to a complete stop. It is well documented that the Teslas have a problem with stopped vehicles in its path.


So you weren't on autopilot. You were driving and not paying attention and ran into something...


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