Auto steer isn’t slowing down in time.. (M3)

[maxiedaniels]

For the most part, the auto steer feature has been amazing. It sometimes gets a bit close to an edge, but overall, solid. But yesterday on the freeway, I had 7 cars lengths as my distance setting, and traffic suddenly cleared up. Once my car was up to 70mph, I noticed the traffic building up again. The car ahead of me had come to almost a full stop. Rather than gradually slowing, my car had to slam on the brakes because it didn’t even attempt to brake until it had gotten probably seven car lengths away. By the time it actually stopped, I was probably one car length away.

Is this how everyone’s car works? It seems like it’s obeying the car lengths rule as a way to determine when it starts to brake, and doesn’t account for the speed of the car. It feels pretty dangerous..

 

[whoosierdaddy]

Yea sometimes you get a nice slowdown and sometimes it acts like it was texting and didn’t see the car stopping up ahead

 

[MLXXXp]

I had 7 cars lengths as my distance setting

The following distance setting is not in car lengths. It seems to be mostly based on the time gap but other (unknown) factors are also involved in the determination (speed limit? road type? amount of traffic?).

From the manual:

Each setting corresponds to a time-based distance that represents how long it takes for Model 3, from its current location, to reach the location of the rear bumper of the vehicle ahead of you.

Note that it doesn't say "the number of seconds", just a relative time.

 

[AlanSubie4Life]

Rather than gradually slowing, my car had to slam on the brakes because it didn’t even attempt to brake until it had gotten probably seven car lengths away. By the time it actually stopped, I was probably one car length away.

This is normal.

Is this how everyone’s car works?

Yes. Generally speaking it sucks. No one knows exactly why and whether it is limited by perception or just bad programming.

Inconsistent. Sometimes (relatively uncommon) it slows down in sufficient time smoothly. Sometimes not. Vision only or blended both have the issue. FSD Beta also has this issue.

I hope one day it can be better, but no idea whether it is possible with existing hardware.

 

[Dewg]

For the most part, the auto steer feature has been amazing. It sometimes gets a bit close to an edge, but overall, solid. But yesterday on the freeway, I had 7 cars lengths as my distance setting, and traffic suddenly cleared up. Once my car was up to 70mph, I noticed the traffic building up again. The car ahead of me had come to almost a full stop. Rather than gradually slowing, my car had to slam on the brakes because it didn’t even attempt to brake until it had gotten probably seven car lengths away. By the time it actually stopped, I was probably one car length away.

Is this how everyone’s car works? It seems like it’s obeying the car lengths rule as a way to determine when it starts to brake, and doesn’t account for the speed of the car. It feels pretty dangerous..

For the most part, yes. It changes a little every update. A few updates ago it was more gentle for me. It's just a matter of tuning. Lots of complaints of aggressive acceleration, so expect next update will swing the pendulum the other way.

 

[AlanSubie4Life]

Lots of complaints of aggressive acceleration,

The acceleration is not aggressive. It may not be smooth, it may be jerky, and accelerate at inappropriate times, but it is not aggressive in the latest FSDb (b). In my opinion it is a lack of smoothness that is the problem. Not a new problem!

The car can accelerate MUCH faster and still be smooth and inspire confidence, in theory. They’re way down the scale and the car is extremely timid at the moment. Obviously, rapid acceleration is not incompatible with smoothness.

 

[Big Dog]

The acceleration is not aggressive. It may not be smooth, it may be jerky, and accelerate at inappropriate times, but it is not aggressive in the latest FSDb (b). In my opinion it is a lack of smoothness that is the problem. Not a new problem!

The car can accelerate MUCH faster and still be smooth and inspire confidence, in theory. They’re way down the scale and the car is extremely timid at the moment. Obviously, rapid acceleration is not incompatible with smoothness.

The early deliveries (mine was Apr-18) would accelerate much faster from a standing stop on the highway on Autopilot. It could be head-bobbing for passengers not paying attention. Fortunately (unfortunately?), they throttled that back to be smoother.

 

[RTPEV]

I've grown to trust AP to slow down even when traffic ahead is starting to slow down quickly. But only when said traffic is already moving along just ahead of me. Even then it tests my comfort level.

When traffic is STOPPED at a distance well ahead of me? That's a different story altogether. I am not willing to test the car's ability to really slam on the brakes, although I have tried to be patient and see how far it will get. So far I have not been able to wait it out past a point I felt comfortable with.

I suspect what is going on is that the car only "sees" a certain distance ahead (that probably corresponds to when the car ahead first becomes visible on the visualization). If following in traffic and tracking the car ahead, it will be able to slow down just fine (if even aggressively) as the car ahead slows rapidly. But if I am coming up on stopped traffic at 70mph and it's not going to "see" the cars ahead until that point in time when it shows up on the visualization, sorry, but that is way too late for me to feel comfortable, and I certainly don't feel like being rear ended.

I also do worry sometimes when approaching stopped traffic and there IS a car ahead of me that is being tracked. I've seen that car not pay attention and swerve out of the way at the last second to reveal a stopped car ahead of it. That was always a cool feature of radar that it could see through (under?) the car ahead. I do worry about how the vision only system would handle such a last minute swerve.

At any rate, when I see stopped traffic ahead, I no longer wait it out. I just disengage AP now. I know I'm going to eventually do it anyway, so why wait. Maybe this is something the higher resolution cameras will help with (increasing the visual distance it tracks ahead).

 

[FLMan]

It did this consistently (hard stop) in the main releases prior to whatever was out in May 2022. When that release came out it seemed to be able to "see" the brake lights ahead and very consistently slowed in time gradually for a smooth stop. This is in stop and go as well as into completely stopped ahead with me coming "at speed" from behind.

I just got the FSDb and it seems to be somewhere in between the others but more on the gradual slowdown side. I also can see on the screen that it "sees" the brake lights ahead. I've used NOA and FSDb in heavy rush-hour traffic and it never fails to stop in time. I often joke with people that it's the first cruise control where I have to keep my foot near the accelerator and not the brake because I have no doubt that it will brake, often. Only once, when all lanes stopped suddenly on the highway did it not know what to do. It slammed the brakes like everyone else but then it disengaged and beeped and I had to continue with the brakes so as not to hit someone.

There are a lot of tourists driving on the highways around me and I trust NOA and FSDb to mostly do the right thing on the highway. Off the highway I haven't had a lot of luck with it doing the right thing. It drives like an anxious drunken teenager.

 

[TresLA]

Vision only or blended both have the issue. FSD Beta also has this issue.

We have one model 3 with and one without FSD beta. I go back and forth between the two quite often and have noticed FSD beta does better at slowing down sooner/more gently. The herky jerky steering wheel whipping is still pretty bad though.

 

[AlanSubie4Life]

We have one model 3 with and one without FSD beta. I go back and forth between the two quite often and have noticed FSD beta does better at slowing down sooner/more gently. The herky jerky steering wheel whipping is still pretty bad though.

I’m sure they are different, but they both have the issue. Interesting that side-by-side comparison seems to show some progress with FSDb. Are they both vision only?