The moment AP slams the brakes on......

[nowtleft]

This has happened on my AP1 car on a number of occasions now and it is very disconcerting. There appears to be no reason for it to happen and I wonder if it happens to everyone and IF you go round again it is repeatable on the same point of road?

Puts me off hands free AP to be honest!

 

[Matias]

I've driven AP1 since it has been introduced and I don't remember that it has ever slammed brakes. I've got very few mild unnecessary braking but newer full braking.

 

[mariopaol]

This has happened on my AP1 car on a number of occasions now and it is very disconcerting. There appears to be no reason for it to happen and I wonder if it happens to everyone and IF you go round again it is repeatable on the same point of road?

Puts me off hands free AP to be honest!

Very common for me. I have noticed a certain reproducibility of this behaviour in the same points on highways.
In particular, there is a highway bifurcation on a straight that triggers the AP to slam the brakes.

 

[Matias]

It is important to distinguish whether we are talking about AP1 or AP2. We all know, AP2 has this problem. As I said, I have not experienced it with AP1.

 

[mariopaol]

It is important to distinguish whether we are talking about AP1 or AP2. We all know, AP2 has this problem. As I said, I have not experienced it with AP1.

Very common for me. I have noticed a certain reproducibility of this behaviour in the same points on highways.
In particular, there is a highway bifurcation on a straight that triggers the AP to slam the brakes.

Sorry, I forget to mention that mine is a MS 90D AP1

 

[nowtleft]

Mine is AP1 - it brakes hard and I have to speed through it to avoid a potentially dangerous problem with the car behind.

 

[nowtleft]

...I assume Tesla knows as the information is fed back to central office.....needs sorting as seems a common problem with AP.

 

[Nikki's Dad]

Has happened to me three or four times in the past few months (AP1). Not so much "slamming" on the brakes but initiation of braking when driving on the highway at speed - which can be very disconcerting. No idea what triggered it. Of course, I'll take a few false positives over the alternative...

 

[Aieukl378]

This has happened on my AP1 car on a number of occasions now and it is very disconcerting. There appears to be no reason for it to happen and I wonder if it happens to everyone and IF you go round again it is repeatable on the same point of road?

Puts me off hands free AP to be honest!

18000 miles (90% AP1) and that has never happened to me.

1. I only use on divided highways(no secondary roads on AP1). Does this happen on the highway or secondary roads?

2. I don't linger in the right lane. When cars are exiting the highway AP1 may see them as cars slowing down in your lane causing your car to slow down tho there isn't a car in front of you. Maybe this is what your experiencing?

 

[nowtleft]

No this has only happenned on the 3rd (overtaking lane) on UK motorways so tend to be doing high speeds.

 

[S4WRXTTCS]

Does TACC do the same thing to you?

I've never had AP1 completely slam the brakes. I have had sudden slow downs under TACC which are annoying, but the vast majority of ACC systems do have a few false positives.

 

[nowtleft]

does that not worry you? - driving in fast lane at say 80mph and the car slows down suddenly to 40mph for no reason? I think it is unacceptable and potentially dangerous and if Tesla are aware the boffins should disable AP1 and 2 until the issue is fixed. Begs the question what other potentially dangerous things are waiting to happen like veering to the right into another car or similar!
The WHOLE point of autonomous cars is that they MUST be 100% right NOT 99%!

 

[Shock-On-T]

does that not worry you? - driving in fast lane at say 80mph and the car slows down suddenly to 40mph for no reason? I think it is unacceptable and potentially dangerous and if Tesla are aware the boffins should disable AP1 and 2 until the issue is fixed. Begs the question what other potentially dangerous things are waiting to happen like veering to the right into another car or similar!
The WHOLE point of autonomous cars is that they MUST be 100% right NOT 99%!

Incorrect.
The long road to full autonomy has started, and your AP1 car is at about the 10% mark, with 90% being your job.
Over many years these percentages will shift.
In the meantime, keep an eye on your car and take over when it does the wrong thing.

 

[nowtleft]

Incorrect - I agree ref the steering but if it slams the brakes on randonly for NO reason it is unsafe!

 

[BrettS]

does that not worry you? - driving in fast lane at say 80mph and the car slows down suddenly to 40mph for no reason?!

I suspect you’re exaggerating here, but if your car is seriously going from 80mph to 40mph then there is definitely something wrong and you should report it and have it checked out at the service center. I have seen cases where my AP1 car decelerates unexpectedly at times, but if you check the display you should see the reason. Usually for me it’s because a car in an adjacent lane drifts into (or close to) my lane. If that car is going slower than me then my car will drop it’s speed to match that car’s speed to ensure I don’t hit it. But again, in cases like this it’s not the car suddenly slamming on the brakes or dropping from 80 to 40, but it is still a bit disconcerting when it happens.

The other day I actually did have my car unexpectedly slam on the brakes and in that case it was also accompanied by the collision warning beeps and a red car on the display. It happened during a very heavy rain when the car somehow detected a phantom car in front of it. (The red car that showed on the display and triggered the collision warning didn’t actually exist and was likely caused by the heavy rain interfering with the camera and/or radar). But even in this case the car didn’t lose much more than 10 or 15mph before it recovered and continued on it’s way.

As other’s have stated, the technology is certainly not 100% right now and there are cases where it does unexpected things, but this is why it’s important to realize that you need to still pay attention when autopilot is engaged and be ready to take over in cases where it fails. If this makes you uncomfortable then you probably shouldn’t use autopilot at this point.

However, that said, if this is something that’s happening frequently and you really don’t see any explaination for it by looking at the car’s display (and especially if you’re really seeing the speed drop from 80 to 40) then that does sound abnormal and you absolutely should have the car checked out.

 

[nowtleft]

I agree and will monitor a while longer. First occasion there was a copper ½ up the road so it did help!

 

[Shock-On-T]

Incorrect - I agree ref the steering but if it slams the brakes on randonly for NO reason it is unsafe!

It doesn't slam on the brakes. It brakes more gently than that.
It doesn't do it for no reason. It does it because it is cautiously responding to an ambiguous radar response.

The braking gives you time to either:
a. over-ride by pressing the accelerator, or
b. actually slam on the brakes to avoid a collision

As an added bonus, when you over-ride the brakes it flags the event as a false positive at that location. This information is used to improve the whole fleet over time.

 

[mariopaol]

It doesn't slam on the brakes. It brakes more gently than that.
It doesn't do it for no reason. It does it because it is cautiously responding to an ambiguous radar response.

The braking gives you time to either:
a. over-ride by pressing the accelerator, or
b. actually slam on the brakes to avoid a collision

As an added bonus, when you over-ride the brakes it flags the event as a false positive at that location. This information is used to improve the whole fleet over time.

Agree. It does not slam the brakes. When it happens, it activates the regen roughly at half power. Therefore, you have the time to override.

 

[SDRick]

Never happened to me in over one year of ownership l