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Autopilot not detecting speed change

I think it will adjust speed in certain situations (e.g. slowing to a safe speed for a turn or a freeway exit). But in general I think it does not. The easy shortcut I picked up on these forums is, after the speed limit changes, a long press on the AP engage lever adjusts to the current speed limit.
 
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I think it will adjust speed in certain situations (e.g. slowing to a safe speed for a turn or a freeway exit). But in general I think it does not. The easy shortcut I picked up on these forums is, after the speed limit changes, a long press on the AP engage lever adjusts to the current speed limit.
Wow. I am surprised. I thought it would be a basic function .
 

house9

Member
Supporting Member
Nov 16, 2019
424
502
California
Driving on autopilot in a road where the speed changes constantly however my autopilot doesn’t detect these changes. I can see the speed signs on the screen but my car doesn’t adjust it.
Is it normal? Do I need to enable something?
Are you sure you are driving with Autopilot or just "Traffic-Aware Cruise Control"?

Cruise Control is configurable to either hold its speed (default?) or match speed limit (with offset).
 

Frank99

April 2018 Model 3 LR RWD, EAP, FSD
Apr 7, 2016
402
546
Arizona
On autopilot, mine (mostly) tracks speed limit changes. It always slows for lower limits, but sometimes doesn’t speed back up when the limit rises (though the screen shows that it knows what the new limit is).
I’m guessing that house9 has it right-you’re on cruise control rather than AP.
 

jjrandorin

Moderator, Model 3, Tesla Energy Forums
Moderator
Nov 28, 2018
14,248
17,986
Riverside Co. CA
I think it will adjust speed in certain situations (e.g. slowing to a safe speed for a turn or a freeway exit). But in general I think it does not. The easy shortcut I picked up on these forums is, after the speed limit changes, a long press on the AP engage lever adjusts to the current speed limit.

When I search TMC for "does autopilot read speed limit signs"

I get the following threads that might help:


There are a few more as well, if you would like to read what peoples experience here on TMC has been with this feature.
 

house9

Member
Supporting Member
Nov 16, 2019
424
502
California
Sorry , I am
Driving on cruise control.
As far as I know it holds the speed, you can use the right side wheel control to increase/decrease speed manually, but it will only slow down automatically if cars are in front of you going slower.

I believe there is a setting to change this to follow speed limit now but I have not tried it. Check the manual for details.
 
it is good to know that cruise control is configurable because I find it very annoying, if not downright dangerous at present when I select a safe speed for the conditions and engage cruise, to have it accelerate to what it thinks is the speed limit which is sometimes wrong.
Autopilot is very dangerous on single lane country roads as it regularly tries to take over when I move over to pass an oncoming vehicle, complete with hazard alarm. I have been driving on such roads for 45 years without incident and this piece of *sugar* thinks it knows better than I???
The auto panic braking is also a health hazard as it balks at centre barriers when changing lanes.
Unless these ‘features’ can be turned off Tesla can have this model 3 back for a full refund!
 
When I search TMC for "does autopilot read speed limit signs"

I get the following threads that might help:


There are a few more as well, if you would like to read what peoples experience here on TMC has been with this feature.
Appreciate the links. There are 2 things here.
  1. Does the car recognize speed limit signs? Yes, and I think it does a good job of this where signage is good. Your links address this aspect.
  2. Does AP adjust the set speed according to posted speed limits? I believe this is really the thrust of the OP's question, and I think the answer is basically "no".
The cars with FSD beta seem to react properly to changes in posted speed limit. Once FSD beta goes into wide distribution, perhaps this is a feature that will later trickle down to NOA & TACC. Or it might stay with FSD only. Fingers crossed.
 
I have the same problem too. It is a pretty serious flaw if cruise control and autopilot have you unintentionally speeding. My model 3 FSD goes the speed set in the max speed icon and does not change with changes in the recognized speed limit. ( It also cant recognize school speed zones, which should be a pretty easy fix. States won't approve self driving operation as long as the car is guaranteed to break speed limits.
 
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Randy Spencer

Supercharger Hunter
Mar 31, 2016
4,316
4,816
Alameda, CA
The worst problem is the bug where it enters the TRUCK speed limit after initially showing the actual speed limit on the display. This happens so often that I don't trust the car to show the correct speed limit, if I see it says 55 I assume that means the actual limit is 65 or 70 and then set my speed accordingly... Dangerous, FIX THIS Tesla!

But yeah, this thread should be abandon, know that the set speed of your car is set by you and not by the signs on the highway, and that if you have auto steer enabled than certain roads will have a max of +5 MPH over the posted limit which will cause the car to slow in situations like entering a town and accelerate leaving those towns as the car attempts to reach the speed you have set, but for most freeway driving the set speed is not changed by speed limit changes.
 
Driving on autopilot in a road where the speed changes constantly however my autopilot doesn’t detect these changes. I can see the speed signs on the screen but my car doesn’t adjust it.
Is it normal? Do I need to enable something?
Mobileye owns a patent for reading road signs through auto software in the US which prohibits Tesla from reading signs to adjust the speed. What you see on your display is just for information. Tesla has not figured a legal work-around yet. The speed limit is adjusted exclusively through GPS data and is 90% of the time wrong. I twitted many times asking if they will sort this out but no response from anyone. This is a know issue at Tesla and quite a shameful one as much cheaper cars (like our Peugeot e208) read road signs with killer precision. Do not expect this sorted any day soon. Do not choose speed relative to road speed, use only relative to the driver setting and pay attention to the road.
Another thing connected to this issue is that until they sort this up they will never be able to activate FSD for all cars before 2020. (Before 2016 for different reasons but 2016 to 2020 for AP2 patents)

Noone is speaking about this but it is sadly true. A little google search will give you all the answers.

Here is the patent:

This issue affects all AP2 Teslas. That means more or less all Teslas between early 2016 and late 2019

 
The worst problem is the bug where it enters the TRUCK speed limit after initially showing the actual speed limit on the display. This happens so often that I don't trust the car to show the correct speed limit, if I see it says 55 I assume that means the actual limit is 65 or 70 and then set my speed accordingly... Dangerous, FIX THIS Tesla!

But yeah, this thread should be abandon, know that the set speed of your car is set by you and not by the signs on the highway, and that if you have auto steer enabled than certain roads will have a max of +5 MPH over the posted limit which will cause the car to slow in situations like entering a town and accelerate leaving those towns as the car attempts to reach the speed you have set, but for most freeway driving the set speed is not changed by speed limit changes.
The problem is that GPS or road sign data can spook the cruise control commands and i have been in many situations where i was doing 100KPH on the high way with CC activated and it dropped to 40 because it thought i was driving on a side low speed limit road... almost made us have a collision and everyone (including the kids) woke up violently. I hate AP and the fact that you cannot overide any features...
 

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