Traffic aware cruise control behavior

[3sr+buyer]

So the Model 3 is the first car that I have had with any kind of adaptive cruise control... so I tried using it a few times. Noticed some behavior that made me less confident in using it:

1. It has adjustable following distance, but even the largest following distance (setting of 7) seemed to be closer than I like. If I am behind a slower vehicle, I prefer to leave more following space, so that when a space opens up in the next lane, I can use the following space to accelerate as I merge into the next lane to pass.
2. When approaching a slower vehicle ahead, it keeps the set speed until it reaches the set following distance and then abruptly slows down, rather than slowing down more gradually to match the slower vehicle's speed by the time the set following distance is reached.
3. Once, while driving in the right lane of the freeway with three lanes each direction and no traffic (or anything but empty road) nearby ahead in any lane, it abruptly slowed down for no apparent reason.

Anyone else have similar or other issues with the traffic aware cruise control? Is this type of behavior (at least #1 and #2 above) typical for adaptive cruise control in other cars?

 

[NeutronStar]

I have 2022 MYLR and I observe exactly items 1 and 2. I am used to much more following distance. I often use the right scroll wheel to slow down and keep more distance.

 

[spsheridan]

3. Once, while driving in the right lane of the freeway with three lanes each direction and no traffic (or anything but empty road) nearby ahead in any lane, it abruptly slowed down for no apparent reason.

This unsettling behavior is referred to as phantom braking and is a well-known problem with Teslas. You can search the term in this forum and in Google and you'll find many examples. Tesla says they're working the problem but it persists.

 

[spsheridan]

This unsettling behavior is referred to as phantom braking and is a well-known problem with Teslas. You can search the term in this forum and in Google and you'll find many examples. Tesla says they're working the problem but it persists.

Here's a recent article about the National Highway Traffic Safety Administration's investigation of Tesla phantom braking.
US government investigates Tesla cars after reports of unexpected braking

 

[3sr+buyer]

I have 2022 MYLR and I observe exactly items 1 and 2. I am used to much more following distance. I often use the right scroll wheel to slow down and keep more distance.

It is almost as if the TACC was programmed to emulate the common but poor driver behavior of racing up to a slower vehicle and then slamming on the brakes when getting close enough to be in imminent danger of crashing into the slower vehicle.

But then maybe it is like the roll-through-stop-signs behavior that FSDB apparently had for a while -- could it be that the developers with poor driving skills programmed it to emulate their own poor driving habits rather than emulating safer and smoother driving skills?

 

[Pacernow]

All,
Is the following distance adjustable in 2021 MY when using cruise control? Can the following distance feature be turn off? A large prt of my driving is two lane highways. Traffic awareness cruise control is see the oncoming traffic and applying the brakes. Today I drove 250 miles on two lane highways and the brakes were applied because I was using the traffic awareness cruise control. It was a miserable trip and experience with this Y. Very disappointed and dissatisfied.

 

[sleepydoc]

Welcome to TACC. This is NOT what adaptive cruise should be or what it is on virtually any other car. We have a Subaru and the adaptive cruise works perfectly on it. A coworker has had identical experience with her Tesla and Subaru.

You will find all sorts of excuses as to why it doesn’t work, but in the end it doesn’t change the fact that it doesn’t work.

 

[Raurele]

Welcome to TACC. This is NOT what adaptive cruise should be or what it is on virtually any other car. We have a Subaru and the adaptive cruise works perfectly on it. A coworker has had identical experience with her Tesla and Subaru.

You will find all sorts of excuses as to why it doesn’t work, but in the end it doesn’t change the fact that it doesn’t work.

Works flawlessly for me. Lane changing, cruise control, autopilot, traffic light control. And I drive 150-200 miles a day on basically every Bay Area freeway. Probably only drive 10 miles of it manually. I must have a unicorn.

 

[sleepydoc]

Works flawlessly for me. Lane changing, cruise control, autopilot, traffic light control. And I drive 150-200 miles a day on basically every Bay Area freeway. Probably only drive 10 miles of it manually. I must have a unicorn.

Congratulations! You got the one that works! That’s been a puzzle to me - there are some people like you that claim to never have problems while others have far more. Why is that? Some of the people are clearly the fanboy type - they never have a problem and dismiss anyone else that does as making it up, driving wrong, etc. It’s the Tesla equivalent of “you’re holding it wrong.” Others are not, though, and it’s a mystery why two ostensibly identical cars can behave so differently.

Actually, from your description, it sounds like you’re using it in heavier traffic which makes me wonder if that’s why it does better for you. When I think about it, I haven’t had much/any phantom braking in stop and go traffic or moderate traffic where there’s a car in front of me. It’s usually on emptier roads.

 

[Raurele]

Congratulations! You got the one that works! That’s been a puzzle to me - there are some people like you that claim to never have problems while others have far more. Why is that? Some of the people are clearly the fanboy type - they never have a problem and dismiss anyone else that does as making it up, driving wrong, etc. It’s the Tesla equivalent of “you’re holding it wrong.” Others are not, though, and it’s a mystery why two ostensibly identical cars can behave so differently.

Actually, from your description, it sounds like you’re using it in heavier traffic which makes me wonder if that’s why it does better for you. When I think about it, I haven’t had much/any phantom braking in stop and go traffic or moderate traffic where there’s a car in front of me. It’s usually on emptier roads.

I use it going 80 for long stretches, and in heavy traffic at various times of the day. My job has me all over. From Sacramento, to Santa Cruz, to the Golden Gate Bridge. It’s honestly flawless for me. Can’t wrap my head around everyone’s problems. The only explanations I can ever think of are hardware issues or miscalibrated cameras.

 

[sleepydoc]

I use it going 80 for long stretches, and in heavy traffic at various times of the day. My job has me all over. From Sacramento, to Santa Cruz, to the Golden Gate Bridge. It’s honestly flawless for me. Can’t wrap my head around everyone’s problems. The only explanations I can ever think of are hardware issues or miscalibrated cameras.

Yeah, I don’t have an explanation for it either. I’m glad it’s working well for you, though. It’s frustrating for me and others.

I can’t say that TACC is unusable, but it’s definitely less enjoyable. In other cars I’ve driven with adaptive cruise you more or less set it and forget it whereas in my Tesla I set it and every 10-15 minutes feel the car suddenly slow down for 5-10 MPH, then accelerate back to speed. (about as strong as ’aggressive’ regenerative braking) Not dangerous, but annoying to everyone in the car as they sway to and fro. Occasionally it will blare the collision alert (except with no message on the screen.) The first response is to take a panicked look around because you think you missed something, then you realize it’s just the car again and you can let your blood pressure drop. Not the most relaxing experience.

What software version are you using? Are you using TACC, AP or FSD?

 

[strider]

In the early days, TACC used separate code and only used the RADAR, so it worked like other manufacturer's TACC. Never had phantom braking and it "just worked."

At some point they got rid of the TACC code and now TACC uses AP/FSD code. TACC has been horrible ever since. I get constant phantom braking (overpasses, overtaking vehicles, etc). Also, the car will slow down for curves based on that AP/FSD thinks should be done. For example, in 65mph zone, I tend to have TACC set at 70mph. When approaching a series of curves that the car can easily handle at 70mph, the car will slow down to ~63mph for the curve and then speed back up again. There is no traffic - it is slowing for the curve.

I HATE that this car thinks for me. The car SUCKS as a driver (AP/FSD is complete garbage) yet it thinks it knows better than I. I wish there was a menu setting to go back to dumb cruise. I am capable of driving my car WAY better than it can and I'm not on my phone while driving.

 

[Raurele]

Yeah, I don’t have an explanation for it either. I’m glad it’s working well for you, though. It’s frustrating for me and others.

I can’t say that TACC is unusable, but it’s definitely less enjoyable. In other cars I’ve driven with adaptive cruise you more or less set it and forget it whereas in my Tesla I set it and every 10-15 minutes feel the car suddenly slow down for 5-10 MPH, then accelerate back to speed. (about as strong as ’aggressive’ regenerative braking) Not dangerous, but annoying to everyone in the car as they sway to and fro. Occasionally it will blare the collision alert (except with no message on the screen.) The first response is to take a panicked look around because you think you missed something, then you realize it’s just the car again and you can let your blood pressure drop. Not the most relaxing experience.

What software version are you using? Are you using TACC, AP or FSD?

2022.4.5.3 2022 MYP. FSD non beta

 

[Raurele]

In the early days, TACC used separate code and only used the RADAR, so it worked like other manufacturer's TACC. Never had phantom braking and it "just worked."

At some point they got rid of the TACC code and now TACC uses AP/FSD code. TACC has been horrible ever since. I get constant phantom braking (overpasses, overtaking vehicles, etc). Also, the car will slow down for curves based on that AP/FSD thinks should be done. For example, in 65mph zone, I tend to have TACC set at 70mph. When approaching a series of curves that the car can easily handle at 70mph, the car will slow down to ~63mph for the curve and then speed back up again. There is no traffic - it is slowing for the curve.

I HATE that this car thinks for me. The car SUCKS as a driver (AP/FSD is complete garbage) yet it thinks it knows better than I. I wish there was a menu setting to go back to dumb cruise. I am capable of driving my car WAY better than it can and I'm not on my phone while driving.

Slowing for the curve is the best feature. I don’t want to feel nervous going around a bend. I drive on the fastest curvy road in the Bay Area every day for 30 miles both ways. It goes between 50-65 the whole time and I’m hands free. It’s a good thing.

 

[strider]

Slowing for the curve is the best feature. I don’t want to feel nervous going around a bend. I drive on the fastest curvy road in the Bay Area every day for 30 miles both ways. It goes between 50-65 the whole time and I’m hands free. It’s a good thing.

You are certainly correct for AP/FSD, but not for TACC. Cruise Control has 1 job - maintain a set speed. Traffic Aware Cruise Control has 2 jobs - maintain a set speed unless there is traffic going slower than your set speed. Slowing for a curve it not one of its jobs.

If you need to change speeds for curves, you should disengage cruise control or not be using it in the first place.

 

[sleepydoc]

You are certainly correct for AP/FSD, but not for TACC. Cruise Control has 1 job - maintain a set speed. Traffic Aware Cruise Control has 2 jobs - maintain a set speed unless there is traffic going slower than your set speed. Slowing for a curve it not one of its jobs.

If you need to change speeds for curves, you should disengage cruise control or not be using it in the first place.

I'll disagree with you slightly here - I routinely use cruise control in town on lower speed roads as it's the best way to avoid speeding, especially with a car like a Tesla that has a very responsive accelerator. In town there are routine cases where roads will curve and you need to slow down. In every other car I would simply disengage the cruise control in these situations, so it's really not much different with a Tesla. Regardless of what car you're driving, you can't assume it's going to do the right thing; you're the one in charge of the car.

 

[S4WRXTTCS]

Slowing for a curve it not one of its jobs.

Slowing for curves is most definitely a job TACC does.

I remember when it was added to AP1

A few people including me complained because they didn't give us any option to turn it off.

I often have to disengage it (I don't overwide as I like to regain full control) because it tries to drive like miss daisy around curves. It doesn't seem to understand the 10 over the caution speed rule.

If you're referring to adaptive cruise control only (like other cars have) then you're entirely correct in that slowing for curves isn't something it does. Like adaptive cruise control in my Jeep won't slow for curve.

 

[strider]

I'll disagree with you slightly here - I routinely use cruise control in town on lower speed roads as it's the best way to avoid speeding, especially with a car like a Tesla that has a very responsive accelerator. In town there are routine cases where roads will curve and you need to slow down. In every other car I would simply disengage the cruise control in these situations, so it's really not much different with a Tesla. Regardless of what car you're driving, you can't assume it's going to do the right thing; you're the one in charge of the car.

I agree that I am in charge of the car. But I have the opposite problem that you list. My Tesla will slow down for a curve when it doesn't need to do so. I regular drive on the Interstate. Interstates have very gentle curves. When going through a particular section near my home, the speed limit is 65 and I like to drive 73. The car (and I) can EASILY take these curves at 73, yet if the car is on cruise control it will slow down to 65 or less. Why is it doing that? I didn't tell it to slow down. The car thinks it's smarter than me but I can promise you that having driven Teslas for years, there is not a single situation that AP/FSD is a better driver than I am.

Obviously, if you engage AP I would expect it to adjust its speed for curves based on its own capabilities (which as stated are terrible - 16 year olds with the ink still wet on their licenses are better drivers than AP/FSD, but I digress), but not cruise control.

Slowing for curves is most definitely a job TACC does.

I remember when it was added to AP1

A few people including me complained because they didn't give us any option to turn it off.

I often have to disengage it (I don't overwide as I like to regain full control) because it tries to drive like miss daisy around curves. It doesn't seem to understand the 10 over the caution speed rule.

If you're referring to adaptive cruise control only (like other cars have) then you're entirely correct in that slowing for curves isn't something it does. Like adaptive cruise control in my Jeep won't slow for curve.

Sorry if I wasn't clear in my post. I agree with everything you said. TACC in a Tesla should work like TACC in every other car. Hold the speed I set unless there is a car in front of me. If you want the car to slow for curves and do other things for you, engage AP.

Heck, I would prefer old school CC where it holds a speed no matter what. They could easily make that a menu option but refuse to because Tesla thinks that AP/FSD works and everyone should use it.

 

[S4WRXTTCS]

I agree that I am in charge of the car. But I have the opposite problem that you list. My Tesla will slow down for a curve when it doesn't need to do so. I regular drive on the Interstate. Interstates have very gentle curves. When going through a particular section near my home, the speed limit is 65 and I like to drive 73. The car (and I) can EASILY take these curves at 73, yet if the car is on cruise control it will slow down to 65 or less. Why is it doing that? I didn't tell it to slow down. The car thinks it's smarter than me but I can promise you that having driven Teslas for years, there is not a single situation that AP/FSD is a better driver than I am.

Obviously, if you engage AP I would expect it to adjust its speed for curves based on its own capabilities (which as stated are terrible - 16 year olds with the ink still wet on their licenses are better drivers than AP/FSD, but I digress), but not cruise control.

Sorry if I wasn't clear in my post. I agree with everything you said. TACC in a Tesla should work like TACC in every other car. Hold the speed I set unless there is a car in front of me. If you want the car to slow for curves and do other things for you, engage AP.

Heck, I would prefer old school CC where it holds a speed no matter what. They could easily make that a menu option but refuse to because Tesla thinks that AP/FSD works and everyone should use it.

How has your experience been on the XC40 Recharge regarding its driver assist features like adaptive cruise control?

 

[Blue Eagle]

I am a new owner of a 2022 MS LR. While I love how TACC works on the open highway, I am shocked how poorly it does in stop and go traffic on the interstate. Namely:

1) I see cars stopped ahead. The car in front of me is slowing down. Yet my car races up and then slams on the breaks.
2) The car ahead starts to drive away. My car sits there. Once it decides to go, it launches rather than smoothly accelerating and maintaining distance.

Oh... and I think I've had two phantom breaking events in my two weeks of owning it. Everything went OK, but I almost got rear ended by a Corolla.