TACC forcing a speed reduction in same location

[golfcaddy]

I did a search and couldn't find a thread about this.

Had my MY since mid Dec 2023. Been using TACC a lot more and getting used to it (including the odd Phantom Braking issues).

However, I'm finding that there is a specific section of road that I travel on regularly where the TACC Max speed drops to 50 from 70 mph and the car starts braking. At first I thought it was phantom braking, but I've now done that same route many times with TACC enabled and it kicks in at the exact same location every time.
(I'm in the UK and it is both directions on the link roads between the M27 and M3).

For a number of years, there was a 50mph speed restriction due to long-running roadworks. That was lifted around 4 or 5 months ago and it is 70mph all the way through.

Now it's happened a few times, I've noticed that the "Max" speed for TACC on the display drops to 50mph at those points and the car brakes. However the display showing the max speed of the road is still showing as 70mph.

I'm assuming this is outdated map data that is screwing up the TACC? I can't think of any other explanation.

Anything that can be done about it, other than remember to turn of TACC before that point and then turning it back on again?

 

[Padelford]

Outdated map data is your explanation. You’ll have to wait for a map update to fix the speed drop.

 

[KArnold]

I've been waiting 10 months now for a similar situation. Don't hold your breath.

 

[OxBrew]

I have one that's been just over 2 years. The road was realigned. For months the maps were old, then the maps got updated and the car shows up on the right road. For a year now, it's all looked correct, but it still drops from 65 to 55 at one weird spot. The speed limit does not drop, the car even has that right.

I just laugh at it now, hover over the go pedal and keep it at speed. It's actually one of the only places I still use TACC, just for the entertainment value. I don't trust any AP features, drive manually most of the time. I think it keeps me young, and it's less mental load to just drive, vs monitoring a novice 16 yr old driver (AP).

 

[emmz0r]

The speed data is all over the place and Tesla relies on both visual and map data and there's constantly some conflict between them. Can drive past temporary signs, and 50% of them get detected, then suddenly it increases to the map speed and vice versa.
Some places it just drops to speed limits of neighboring roads.

 

[kimwin]

Slowing down is not a big issue for me. It's the not slowing to match current street limit is a problem. In Hawaii, I drove on.a highway at 60 mph, speed limit for about 20 miles, suddenly there are signs showing only 40mph.
If the car does not automatically reduces speed and the driver only pay attention to avoid accidents, he/she could get a speeding ticket easily. Hawaii has many speed traps like this.

 

[snibble]

I did a search and couldn't find a thread about this.

Had my MY since mid Dec 2023. Been using TACC a lot more and getting used to it (including the odd Phantom Braking issues).

However, I'm finding that there is a specific section of road that I travel on regularly where the TACC Max speed drops to 50 from 70 mph and the car starts braking. At first I thought it was phantom braking, but I've now done that same route many times with TACC enabled and it kicks in at the exact same location every time.
(I'm in the UK and it is both directions on the link roads between the M27 and M3).

For a number of years, there was a 50mph speed restriction due to long-running roadworks. That was lifted around 4 or 5 months ago and it is 70mph all the way through.

Now it's happened a few times, I've noticed that the "Max" speed for TACC on the display drops to 50mph at those points and the car brakes. However the display showing the max speed of the road is still showing as 70mph.

I'm assuming this is outdated map data that is screwing up the TACC? I can't think of any other explanation.

Anything that can be done about it, other than remember to turn of TACC before that point and then turning it back on again?

Fyi same issue on A1 north around Stamford.
Old road works limit still active

 

[SidetrackedSue]

Haven't had a chance to try this since 2024.3.10 but we have one spot on the freeway to our son's where the car will slow. Since we know the building we are passing when it happens, we are ready to press the go-pedal. The speed limit sign on the screen doesn't change so the car isn't following the speed indicated on the screen.

As well, the car shows an 80 kph speed limit sign on the screen just to the west of our local on/off freeway exit (when heading either coming from or going west on the freeway.) The actual speed is 100kph. . The 80 is leftover from construction 4 years ago. The car no longer slows here when in TACC or FSD so the car is not reacting to the displayed speed limit.

Not a TACC issue but the car also thinks the right lane is an exit lane for the exit prior to ours because it didn't exist prior to construction (again, 4 years ago). That means it doesn't use that lane even though the lane usually is open. We have to force the car over to the right, or it will pass on the left anything slower moving in the middle lane, then not be able to get to the right lane to exit. Last night, testing V12 we let it decide how to get off the highway. We had to disengage because it got over to the right lane at the last moment but then forgot to exit. This issue means we tend to use TACC through here instead of FSD and thus will miss the easy "disengage FSD but end up in TACC" mode we had before. This happens over 10 - 15 seconds so is not worth switching profiles. We'll just always disengage and drive the car ourselves and then, since FSDS is much more competent and confident than previous FSDb, we'll reengage until we get to our neighbourhood where it is easier to just drive ourselves since we don't try to hit every pothole and stop fully at the 4 stop signs in 3 blocks.

It really helps to think of all these features as driver assist and to literally pick and choose by turning on/off or overriding as you drive. It isn't as reliable as regular cruise control since you can't set it and forget it;. It will speed up or slow down as it thinks appropriate. On the other hand, it does other things pretty well that other companies aren't offering yet. Until it completely messes up. So you really can't let it drive on FSDS or TACC; you can just let it help you (a lot.)

 

[kimwin]

I tried FSD V12 since Apr-01-2024. It seems to work pretty good but not perfect.
Each time getting near my destination, I press the brake slightly to turn OFF auto-pilot because I like to drive in the parking lot (or my garage) and park the car myself. 30% of the time, I also turn OFF auto pilot because the car take a route that I do not like !!!
Each time I turn OFF auto pilot, the screen pops up a message like "FSD was on, why turning it OFF, press the "mic" and say a few word to tell us your reason for doing so". That is what the message means, I do not remember the exact phrasing.
Question: what do I have to press to say a few words ?