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TACC - Set to Current Speed?

SomeJoe7777

Marginally-Known Member
Mar 28, 2015
2,274
6,087
Houston, TX
Ran into a dilemma this morning that appears to be a fairly large design problem.

Surface street, normal speed limit 45 MPH. Approaching school zone, speed limit 25 MPH when the yellow lights are flashing (they were). I like to set TACC in school zones like this to prevent me from going above the posted speed (cops frequently watch this street and this school zone). I tried several times to set TACC to 25 MPH, and I can't figure out how to do it.

Every time I tried, no matter if it's a half-click down on the stalk, full-click down on the stalk, click and hold, etc., TACC always set itself to speed limit + offset = 50 MPH. There isn't enough time to press and hold the "minus" button on the display 5 times to get the set speed down to 25 MPH before I'm going way too fast.

I the S, you can set TACC to the current speed regardless of the speed limit by a half-click up or down on the cruise control stalk, but no such way to do it in the 3.

Am I missing something here or did Tesla just b0rk this interface?
 
I run into the same scenario everyday on my commute. 35 mph speed limit but based on the time of day drops to a 20 school zone. Total speed trap too as the road is four lanes wide and the local police regularly setup an assembly line of ticketing.

Engaging TACC or AP jumps straight to 40mph (+5 offset setting) and I have to quickly tap the set speed down to 25. Having the scroll wheel control update will help but it still feels strange having the car lurch forward then slow down
 
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SomeJoe7777

Marginally-Known Member
Mar 28, 2015
2,274
6,087
Houston, TX
Ya, there definitely needs to be an interface change here.

In the S & X, the way it works is:
  • Half-click up or down on cruise control stalk sets to current speed, regardless of anything else.
  • One full pull rearwards sets speed to either:
  1. Last set cruise speed if your speed is below that
  2. Current speed if your speed is above that
  3. Speed limit + offset if you don't have a previous set cruise speed
  • Full pull and hold sets speed to speed limit + offset, can be used even while TACC is already engaged (useful for resetting speed downwards or upwards when the speed limit changes)
  • Double-pull turns on autosteer

I would say you could do similar in the 3:

  • Half-click down on stalk sets to current speed
  • Full-click down on stalk sets to either:
  1. Last set cruise speed if your speed is below that
  2. Current speed if your speed is above that
  3. Speed limit + offset if you don't have a previous set cruise speed
  • Full click-down and hold sets to speed limit + offset
  • Double-half click is current speed + autosteer
  • Double-full click is the same as the single full-click described above + autosteer
  • Double-half click when TACC is already active just adds autosteer without changing current TACC settings

Right now, there's no differentiation in the 3 between a half-click down and a full-click down, they both do the same thing. That's where this interface element could be added.
 
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Az_Rael

Well-Known Member
Supporting Member
Jan 26, 2016
5,681
8,983
Palmdale, CA
Wait, wait, wait.....you're telling me that if I'm doing 30 in a 45 and turn on TACC the car will jump up to 45mph???? That's ridiculous. I want it to hold the speed at the time of engagement.

Yup, very annoying. At least with the scroll wheel I can now quickly scroll down to get to my desired set speed. Before I had to frantically tap on the tiny icon on the screen.
 

ratsbew

Active Member
Mar 3, 2012
1,296
1,046
O'Fallon, IL
I read the manual and it's confusing. It says "When driving at your desired speed, set thecruising speed by moving the gear lever fully down once then releasing." And two pages later it says "Traffic-Aware Cruise Control makes it easy to cruise at the speed limit. You can cruise at the speed limit that is currently being determined by Speed Assist. To do so, move the gear lever fully down once then release. When you release, your cruising speed is set to the speed that is determined by Speed Assist."

The same physical action seems to have two different outcomes.
 

Az_Rael

Well-Known Member
Supporting Member
Jan 26, 2016
5,681
8,983
Palmdale, CA
I read the manual and it's confusing. It says "When driving at your desired speed, set thecruising speed by moving the gear lever fully down once then releasing." And two pages later it says "Traffic-Aware Cruise Control makes it easy to cruise at the speed limit. You can cruise at the speed limit that is currently being determined by Speed Assist. To do so, move the gear lever fully down once then release. When you release, your cruising speed is set to the speed that is determined by Speed Assist."

The same physical action seems to have two different outcomes.

In practice, if the car knows the speed limit, pulling down on the stalk will auto set TACC at the speed limit even if you are driving slower. If the car doesn't know the speed limit or you are driving faster, it sets at your current speed.

I haven't tried a half press. That might be new functionality.
 
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In practice, if the car knows the speed limit, pulling down on the stalk will auto set TACC at the speed limit even if you are driving slower. If the car doesn't know the speed limit or you are driving faster, it sets at your current speed.

I haven't tried a half press. That might be new functionality.

Yes I agree with this summary. My new trick with the school zone scenario I detailed earlier in the thread is to engage TACC/AP just before the car figures out the speed limit so I can set it to my current speed.

The scroll wheel update did improve the effort and speed to quickly correct the set speed but this is all still less than optimal. I don’t mind the car jumping straight to the speed limit plus my offset but if so it needs to see the flashing school zone lights :)
 
Don't have my 3 yet, but one other thing you can do is to touch the speed sign on the screen. This is talked about in the manual somewhere. Touch it and it will set to the speed recognized and displayed. I have no idea though for a school zone how it knows if it is normal speed or school speed. So on a week day does it set for 20 in the school zone and on the weekend stay at regular speed? It's reading the signs right?
 

SDKoala

M3LR RWD / MYLR
Apr 11, 2018
874
981
San Diego
This is a big annoyance, especially with the speed limit markings being inaccurate in some areas. In my residential neighborhood with a 25 MPH speed limit, the GPS thinks the speed limit is supposed to be 55 MPH. If I engage TACC when on the road by myself, the car starts to accelerate to 55 MPH unless I quickly set the speed lower. It's impossible to avoid the lurching forward.

This is a big safety issue and the one time the claim that "the car accelerated by itself" could actually be at least partly true. Is there really ever a reason why TACC shouldn't be set to your current speed by default? That's how every other cruise control system I've ever used works.
 
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I see the last post here was May 1. I can confirm that as of firmware 2018.34.1 3dd3072 (9/7/2018), this issue still has not been fixed.

Things I've tried:
  • Push the stalk down half way versus pushing it down all the way. I was trying to copy the behavior seen in the S and X, as above. But, both actions set the TACC to the suggested speed (inside the grey circle). So Model 3 still behaves in a way similar to the other two Teslas but varies in one critical feature.
  • Turn off the Speed Limit Warning. I was actually trying to turn off Speed Assist on the theory that it's 'assisting' TACC. But, apparently, you can't turn off Speed Assist, so turning off the warning had no effect. (Side note: with the warning turned off I could not adjust the relative speed it's supposed to warn me at -- but TACC still used that setting. So if you don't like the warning but do like the relative speed setting for TACC, you have to turn the warning on, sett the offset, then turn the warning back off. Wtf?)
  • All combinations of the above.
This is a huge issue for me. I consider it a safety issue. I find it bitterly ironic that the manual often reminds us that the driver must remain in control of his car when TACC is engaged -- but then they take all control of the speed away from the driver when engaging TACC. Go figure.
 
Let me suggest how it should work (hello, Tesla, is this thing on?). Before engaging TACC, the "set speed" is shown in the little gray circle, and the right scroll wheel doesn't serve any purpose. Simply allow the right scroll wheel to adjust the "set speed" before engaging TACC. TACC always goes to the indicated "set speed", so just let me change that to the # I want.
 
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ratsbew

Active Member
Mar 3, 2012
1,296
1,046
O'Fallon, IL
I think that the best solution is a press down (half or full) to set current speed. HOLD the stalk down for 1 second to accelerate up to the "speed assist" speed...or tap the speed limit icon.

Likewise, with EAP, double tap for current speed, double tap and hold for the speed limit.

People who don't read the manual will be none the wiser about the hold feature and will just use the scroll wheel to accelerate.
 

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