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Autopilot not detecting speed change

Yaely

Member
Mar 20, 2021
31
2
Canada
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?
 

Enginerd

Member
Jun 24, 2017
342
950
Savannah, GA
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.
 

Yaely

Member
Mar 20, 2021
31
2
Canada
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 .
 
  • Disagree
Reactions: Gasaraki

house9

Supporting Member
Nov 16, 2019
346
364
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

Member
Apr 7, 2016
123
145
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
Nov 28, 2018
7,765
8,578
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

Supporting Member
Nov 16, 2019
346
364
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.
 

Yaely

Member
Mar 20, 2021
31
2
Canada
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.
Thanks . I will check
 

Kermit1

New Member
Apr 4, 2021
2
0
Pennyroyal
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!
 

house9

Supporting Member
Nov 16, 2019
346
364
California
Autopilot is very dangerous on single lane country roads
Autopilot is not meant for single lane country roads yet, should be used on freeways and major highways. FSD beta should be able to handle it now, but not sure if that will ever trickle down to Autopilot?
 

Enginerd

Member
Jun 24, 2017
342
950
Savannah, GA
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.
 
  • Informative
Reactions: jjrandorin

Gasaraki

Active Member
Oct 21, 2019
1,475
985
Syracuse, NY
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?
If it's a highway, it will not change the speed from what you set it.
 

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