TACC degradation in stop and go traffic

[gaM3changer]

Has anyone else notice the degradation in TACC while in stop and go traffic? I’ve been using autopilot for over a year now commuting in LA traffic and the last few days (including this morning) TACC has been very jerky. The car will bounce between accelerating and regen while following the car ahead. For the first time since getting the car, I’m starting to feel queasy from all the jerkiness.

I’ve tried a soft reboot this morning, changing the follow distance up and down and even set it to chill mode and nothing has helped. I’ll try doing a full shutdown this evening before my drive home and will report back.

 

[ewoodrick]

Do you have hold on?

 

[gaM3changer]

Do you have hold on?

Hold mode will come on if I’m stopped for a longer period of time.

Sorry, I should have clarified... It’s more heavy traffic with some stop and go. I do not recall seeing hold mode engaging this morning.

Watching the power meter, the car was constantly jumping between black and green.

 

[jdcollins5]

Is this jerkiness consistent? Have you tried following different vehicles? I have had this happen and realized the lead car was changing speed. I have changed lanes and my speed returns to normal.

 

[gaM3changer]

It’s pretty consistent at speeds less than 15 mph since Tuesday. I’m usually in the HOV lane with double yellow lines so switching lanes can only be done at certain spots... maybe I’ll just leave a bigger gap and let someone else jump in ahead of me.

 

[Enginerd]

Before the recent firmware updates, AP would accelerate too slowly and leave too big of a gap. The recent update cured that problem in a big way. Unfortunately, I think the needle swung a little too far in terms of minimizing the gap and delay. Now the car accelerates too aggressively from a stop, and I've experienced the yo-yo feeling you describe, as the car attempts to stabilize the following distance. It's a classic underdamped control system problem. I'm hoping that they realize the turned the knob a little too far with the recent firmware, and dial it back somewhere in the middle.

As they try to make progress in some areas, sometimes characteristics degrade in other areas. As long as the gains outpace the losses, I'm happy enough. It's not a sprint, it's a marathon.

 

[gaM3changer]

Update on this evening's commute... ALL IS GOOD!!!! I did a full shutdown and waited a few minutes before my drive. My first 11 miles took one hour, so there was plenty of stop and go. TACC was very smooth. I tried following different cars, changed follow distance between 1-6 and everything worked smoothly like before, no jerkiness whatsoever.