Cruise control - Random braking and speed reductions... anyone else?

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M3OC Rules

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#41
It does do this on TACC alone, and it does it on the freeway, and it will often suddenly change the speed to 30 mph below the speed limit.
It seems like that must be a map issue and it thinks its an exit ramp. I don't think I've seen this but I'm usually on AutoSteer. I verified today that on TACC alone and TACC+Autosteer do not always act the same. There is one section that I drive that on my commute that is a long entrance ramp. It switches from 55mph to 30mph and then back to 55mph on one section. If I have autosteer on it will lower the speed but if I have TACC only it will not lower the speed through this section. It kind of suggests multiple different types of map errors causing different behaviors on TACC only.
 

Mike

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#42
Nice if it works. On my way to work the street has a 60 km/h speed limit, but the car thinks it's 80 and wants to speed up, so that's not so great. There should absolutely be a setting to turn it off.
I went thru this same crap a year ago, over the first week I owned my TM3.

My ad hoc fix that seems to be the 90% solution is to set "relative" to "minus 30 (kph)" and use "relative".

See this link for more details: https://teslaownersonline.com/threads/learning-curve-speed-assist-and-default-settings.7158/
 

pdp1

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#43
I noticed the following happen at least twice since I updated to 16.2 (see picture below). I'm the green car and I have TACC on with the distance between cars set to 3. The red car in front of me decides to change to the lane to the right, cutting off the blue car. The blue car brakes because of the red car, but it causes my car to suddenly brake as well, which makes no sense to me because I wouldn't have slammed on the brakes in that case. The only far fetched explanation I can think of is that TACC now thinks the red car and blue car are the same car and is using the blue car as rear of the red car to judge distance? Regardless, it has been really annoying.
tes-jpg.26580
 

DocScott

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#44
I noticed the following happen at least twice since I updated to 16.2 (see picture below). I'm the green car and I have TACC on with the distance between cars set to 3. The red car in front of me decides to change to the lane to the right, cutting off the blue car. The blue car brakes because of the red car, but it causes my car to suddenly brake as well, which makes no sense to me because I wouldn't have slammed on the brakes in that case. The only far fetched explanation I can think of is that TACC now thinks the red car and blue car are the same car and is using the blue car as rear of the red car to judge distance? Regardless, it has been really annoying.
View attachment 26580
Maybe it's over-correcting for another issue that has long been, at a minimum, unnerving.

Say it's a three-lane highway with a speed limit of 65 mph and the right lane is bumper-to-bumper, moving at maybe 10 mph stop-and-go. This may be because there's an exit that's backed up, or perhaps a stalled car or the lane closes up ahead. But the middle lane is clear.

Most humans driving in the middle lane will use a little caution, and drive somewhat below the speed limit--maybe 50 mph--just in case someone decides to jump out of the bumper-to-bumper lane. But AP has had a tendency to just assume that the people in the right lane won't be idiots and try to pull out when someone's coming. It's unnerving to have AP charging along at 67 mph (if I'm set at +2) right next to all those cars at 10 mph. In those situations I usually disengage and slow down a bit.

But in more recent updates, I notice AP has sometimes started to become aware of that kind of issue and may drive a little more cautiously in that situation.

The situation you describe may be making AP worried that someone might do something in response to the slowing in the right lane to bring them back in to yours--perhaps the blue car will try to get in to your lane to get around the red one.

A human is smart enough to understand the difference between the situation you describe and, say, a giant pothole in the lane that causes the blue car to brake and then maybe swerve around in to your lane, but AP isn't quite trained well enough to get that distinction yet, and so it slows down out of an abundance of caution.

Just a guess...
 

pdp1

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#45
Maybe it's over-correcting for another issue that has long been, at a minimum, unnerving.

Say it's a three-lane highway with a speed limit of 65 mph and the right lane is bumper-to-bumper, moving at maybe 10 mph stop-and-go. This may be because there's an exit that's backed up, or perhaps a stalled car or the lane closes up ahead. But the middle lane is clear.

Most humans driving in the middle lane will use a little caution, and drive somewhat below the speed limit--maybe 50 mph--just in case someone decides to jump out of the bumper-to-bumper lane. But AP has had a tendency to just assume that the people in the right lane won't be idiots and try to pull out when someone's coming. It's unnerving to have AP charging along at 67 mph (if I'm set at +2) right next to all those cars at 10 mph. In those situations I usually disengage and slow down a bit.

But in more recent updates, I notice AP has sometimes started to become aware of that kind of issue and may drive a little more cautiously in that situation.

The situation you describe may be making AP worried that someone might do something in response to the slowing in the right lane to bring them back in to yours--perhaps the blue car will try to get in to your lane to get around the red one.

A human is smart enough to understand the difference between the situation you describe and, say, a giant pothole in the lane that causes the blue car to brake and then maybe swerve around in to your lane, but AP isn't quite trained well enough to get that distinction yet, and so it slows down out of an abundance of caution.

Just a guess...
You might be onto something there. About 2 hours after my previous post, I was driving home and using Autopilot (I should have said Autopilot in my previous post, not TACC) on the freeway in the right lane, approaching a merge from an on-ramp lane. AP noticed a car approaching down the on-ramp lane, accelerating reasonably fast. A few seconds before said car even started merging onto the freeway, AP had my car to slow down, which was probably the right thing to do. So it seems AP was treating what I described in my previous post the same way as the situation I described in this post. I can see why to an AI both situations would be similar, but a human could tell the difference immediately.
 

Kimmo57

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#46
I went thru this same crap a year ago, over the first week I owned my TM3.

My ad hoc fix that seems to be the 90% solution is to set "relative" to "minus 30 (kph)" and use "relative".

See this link for more details: https://teslaownersonline.com/threads/learning-curve-speed-assist-and-default-settings.7158/
Thank you, that's very helpful. Hopefully I can set it to -40 km/h, since I noticed yesterday, that the car suggested 80 km/h on a little 40 km/h street close to my home :eek: That's 50 mph on a 25 mph street for those using the weird units.
Then if we could just find a solution to the unnecessary braking...
 

bwilson4web

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#47
I verified the GPS map vs location problem tonight.

Entered zone at 50 mph and soon dropped to 40 mph:
tacc_060-jpg.31885

tacc_070-png.31886


In 40 mph zone, it soon goes back to 50 mph:
tacc_080-jpg.31888

tacc_090-jpg.31889


Here I combined a Google map image with icons showing what happens:
tacc_050-jpg.31890

If your duration is short enough, the car in the left lane does not reset the TACC speed. In contrast, a larger zone in the right lane leads to a consistent drop to 40 mph.

Speculation, I suspect the different software releases may have different durations in a zone before the car begins changing speed. It would be great if there were some way to indicate a brief speed zone change for the humans.

Bob Wilson
 

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bwilson4web

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#49
Great. So when will T fix this annoyance?
My BMW i3-REx has 'mobileye' and reads speed signs. When Tesla implements reading speed limit signs, most of these will go away to be replaced with mobileye problems like school zone speed signs when school is out.

In the meanwhile, several suggestions for Tesla:
  • notification of a GPS-Google_Map speed reduction so the driver can understand and respond faster
    • specific bug report for speed anomaly so Tesla can fix map
    • resume original speed after short duration in new zone
    • stay with lead traffic if available
    • 'remember' driver corrected speeds
  • provide an optional, map-independent, cruise control (i.e., old style)
I have another problem with TACC in the neighborhood. If I enable TACC headed south-east-south out, it sets the speed to 45 mph, not the 25-30 mph for a neighborhood. I know about it and EVERY TIME quickly dial it down. In contrast, going home, north-west-north, I can set the speed manually.

LATE EDIT: I got this in a Tesla e-mail:
Thank you for sending in the location and the video. This will very helpful for the autopilot team.
I have sent it on to them for further research and a solution. While I cannot guarantee a time frame of when the issue will be fix, I can tell you they take all of our customers feedback very seriously in order to improve all Tesla vehicles.

Bob Wilson
 
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bwilson4web

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#50
I've posted a YouTube showing the video shared with Tesla. My dashcam was in 'time lapse' mode, ~2 frames/second, which in playback makes the action much faster. However, YouTube has both a playback speed control and the ability to stop and examine the video frame-by-frame.

Reproducible, I subsequently re-ran the left and right lane tests at 20 mph and could see the 'speed sign' icon change. It picks up the speed change but updating the speed sign icon takes longer. Meanwhile, the car drops from 50 mph to 40 mph in ~3 seconds.

LATE EDIT:
I just checked the 'openstbreetmaps' view of the problem area and it shows only a single path mapped at 50 mph for both lanes. This suggests the Tesla GPS coordinates had wandered toward the 40 mph access road.

Bob Wilson
 
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JustTheTip

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#51
I was using TACC the other day. A car turned in front of me onto a side street waaaay ahead of me, and the car practically slammed on the breaks after the car completed its turn. I’m glad nobody was behind me. No doubt I would have been rear ended.