AP and TACC

[Drmouse]

Hi all

Can anyone tell me where AP (autosteer) and TACC are supposed to be used, and/or where they work well.

I know that AP is only supposed to be used on "highways". From what I have read, I think that would be motorways and dual carriageways over here. Can anyone confirm?

What about TACC? I've read conflicting reports. Where is TACC recommended to be used, and can anyone give me their experiences of using it in different situations/road types (motorways, around town, country lanes* etc)?

Just trying to get an idea of this from actual drivers, and I'm asking in UK & Ireland to avoid confusion over naming conventions.

Thanks everyone

(* Although I doubt I'd ever want to use it on country lanes, that's where it's actually fun to drive! Lol)

 

[Ryder35]

You can turn it on virtually anywhere the car detects road markings but that does not mean it is a good idea!

I tend to use Auto steer on DC andf motorways or in jams. TACC seems to work anywhere but does not like oncoming traffic on sharp bends I have found. Can be prone to phantom braking in those situations. (I have only had the car 2 weeks so take that into consideration )

 

[MrBadger]

Take a look at TeslaDriver on YouTube - he's been doing a 'city tour' - some are more informational than others, but a good selection of situations and there may be some areas that you can relate to. He is happy to say what is good and what is bad so fairly balanced although some of his comments may be a little naïve - I think he may be a country lad with limited experience of the big smoke...

 

[WannabeOwner]

I know that AP is only supposed to be used on "highways". From what I have read, I think that would be motorways and dual carriageways over here.

I would also use it on "big" arterial single-lane A-roads, in particular if I was trogging along in traffic on a long stretch. Normally I don't use it on non dual carriageway, that said I have never had an OMG moment - such as heading for oncoming traffic [get an iPace if you want that excitement ...]

I've seen a YouTube video where the guy painted some white lines on his lawn to see how AP would work ... and to extend his drive enough that he could get up to enough speed to engage it. He then tested whether it would stop before running his poor, long suffering, girlfriend over if she stood in the way ... all joking apart AP actually performed pretty well.

I suspect that once you have used it on Dual Carriageway you will define your own "worthwhile here" test.

where AP (autosteer) and TACC are supposed to be used

I engage AP the moment I am on dual carriageway. I have had AP "catch" an incident that I would either have missed (and had an accident) or caught very late (which might have caused an incident behind me when I then braked heavily), so now I wouldn't be without it on appropriate roads.

I use AP whenever I am in bumper-to-bumper crawling traffic, but some people prefer TACC for that

Both those significantly reduce my driver-workload and I arrive much more refreshed (especially on long journeys)

In villages when I am following a car I sometimes engage TACC. That matches my speed to car in front (so no surprises from TACC not realising that the next bend is REALLY sharp!) and keeps safe distance etc. and can reduce my workload somewhat. Ipso facto my speed is below what I would drive at that point, otherwise I wouldn't be behind the car in front and TACC will reduce to speed limit (plus offset) anyway ... AP not suitable for any of the rural villages around here.

The biggest risk with AP is your complacency. Mile after mile, year after year, with zero OMG moments (I'm not including phantom braking in that) and there is significant risk of Driver "just doing a quick text" and that, sadly, is the point at which people have been killed.

I always have a hand on the wheel, and I consider myself "lookout"; much the same as a pilot using autopliot in a plane. My "style of lookout" is different from normal driving, I am looking further ahead, behind, and around than if I was manual-driving. My one piece of advice is to never, ever, assume the car could drive for a few seconds on its own. It may only fail once-in-numerous-car-ownerships, but don't become a statistic.

Take a look at TeslaDriver on YouTube

Sorry, his stuff is dreadful clickbait. I've stopped following him since I noticed that the number of factually wrong things he said had me shouting at the screen.

I find Bjørn Nyland has a very balanced view, and at least he isn't trying to drive to work everyday, on roads inappropriate for AP, on YouTube for the clicks

 

[interbear]

Can someone explain the exact difference between AP and TACC please, plus how each of them are switched on / off? I’m assuming the latter is a form of cruise control which is more akin to what I’m used to on my current car. I only ever use that on motorways or dual carriageways currently so would likely apply the same policy to both of these on the Model 3. But I’d like to know the difference.

 

[phillcom3]

I would also use it on "big" arterial single-lane A-roads, in particular if I was trogging along in traffic on a long stretch. Normally I don't use it on non dual carriageway, that said I have never had an OMG moment - such as heading for oncoming traffic [get an iPace if you want that excitement ...]

I've seen a YouTube video where the guy painted some white lines on his lawn to see how AP would work ... and to extend his drive enough that he could get up to enough speed to engage it. He then tested whether it would stop before running his poor, long suffering, girlfriend over if she stood in the way ... all joking apart AP actually performed pretty well.

I suspect that once you have used it on Dual Carriageway you will define your own "worthwhile here" test.



I engage AP the moment I am on dual carriageway. I have had AP "catch" an incident that I would either have missed (and had an accident) or caught very late (which might have caused an incident behind me when I then braked heavily), so now I wouldn't be without it on appropriate roads.

I use AP whenever I am in bumper-to-bumper crawling traffic, but some people prefer TACC for that

Both those significantly reduce my driver-workload and I arrive much more refreshed (especially on long journeys)

In villages when I am following a car I sometimes engage TACC. That matches my speed to car in front (so no surprises from TACC not realising that the next bend is REALLY sharp!) and keeps safe distance etc. and can reduce my workload somewhat. Ipso facto my speed is below what I would drive at that point, otherwise I wouldn't be behind the car in front and TACC will reduce to speed limit (plus offset) anyway ... AP not suitable for any of the rural villages around here.

The biggest risk with AP is your complacency. Mile after mile, year after year, with zero OMG moments (I'm not including phantom braking in that) and there is significant risk of Driver "just doing a quick text" and that, sadly, is the point at which people have been killed.

I always have a hand on the wheel, and I consider myself "lookout"; much the same as a pilot using autopliot in a plane. My "style of lookout" is different from normal driving, I am looking further ahead, behind, and around than if I was manual-driving. My one piece of advice is to never, ever, assume the car could drive for a few seconds on its own. It may only fail once-in-numerous-car-ownerships, but don't become a statistic.



Sorry, his stuff is dreadful clickbait. I've stopped following him since I noticed that the number of factually wrong things he said had me shouting at the screen.

I find Bjørn Nyland has a very balanced view, and at least he isn't trying to drive to work everyday, on roads inappropriate for AP, on YouTube for the clicks

I think we all could do with a pilots training in regards to lookout as a pilot on autopilot. A pilot upfront. Never looses situational awearnes. He could easily kill everyone on board if he did and that's a hard thing to do at 30kft with only dots and a line to see. At least on the ground there's much more to see. I think that this in kind we can focus more on planning ahead looking for stops and keeping ourselves swear of where we are. Many people start to panic when they realise after a long stretch they have no idea of where they actually are and where a station may be and thus range anxiaty sets in on any car.

 

[WannabeOwner]

Can someone explain the exact difference between AP and TACC please, plus how each of them are switched on / off?

TACC - maintain speed, slow down for traffic in front. Have a stab at slowing down for sharp bends. Cancelled by braking. Not cancelled by accelerator - so you can accelerate-to-pass and then lift off to let TACC resume cruising speed.

If used behind a car in a queue of traffic the car will nudge forward with the traffic; then when car-in-front gets to the front and pulls out YOU will follow best to disengage before then ...

AP - in addition to TACC it will auto steer to stay in lane, and if you have FSD - Full Self-Driving - it will either change lanes to overtake by itself (NOA) or you can signal to change lanes.

AP is cancelled by overriding the steering, which leaves TACC active (braking cancells both)

On M3 press the right stalk fully down for TACC and double-down for AP. M3 engages TACC at current speed limit - which can be alarming if you are not at that speed! Engaging when behind another vehicle avoids that. You adjust speed up/down on screen

MS/MX have more sophisticated dedicated TACC/AP stalks that allows nudge up/down 1MPH and 5MPH, and also "engage at current speed" etc

EDIT: There are circumstances where TACC will adjust speed down when it enters a speed limit, and speed up when it comes out. I've seen numerous threads on this with conflicting advice. On my car I would define it that on Motorway it stays at 70 (but I have known people say that their car adapts for gantry signs), but on non-dual carriageway (i.e. 60 MPH limit) my car will slow for 30 / 40 MPH zones, and speed up when I come out of them.

In all instances the car shows current speed limit on Dash, so its just the circumstances under which TACC adjusts the currently set speed

TACC can be set up to 90 MPH. If AP is on and you accelerate higher than 90MPH then AP will be cancelled for the remainder of the journey. TACC remains available.

 

[spon88]

I don't like AP or TACC to be honest. Until it's consistent (it's not!) I'll be sticking to driving myself. In my testing I felt insecure waiting for the next phantom braking or odd-ball steering episode and so turned it off. Maybe I just need to "learn" it? I will try again but at the moment it's not consistent enough for me to trust it and it only takes a split second for something really bad to happen. Plus I actually enjoy the driving.

 

[Drmouse]

The biggest risk with AP is your complacency.

I understand this is a big problem, and do intend to stay fully aware while using AP (just as I do with CC in my current car).

There is a big misunderstanding with Autopilot, in that people expect it to drive for them. That's not how autopilots work on aircraft, just as you said the pilot must be alert and ready to take control at any point (and most just maintain heading, speed and altitude, not much more than cruise control anyway, so AP is actually more advanced than these).

 

[Yev000]

Interesting.

What about lane keep feature? There are a bunch of traffic jam areas where the lane splits and you want to be almost on the central line. I'm guessing both TACC and AP would be pretty useless there?

 

[Tony Hoyle]

TACC is great in queues. It just follows the car in front and you don't have to worry about it until you get near the front.

AP is best where there are good road markings & few junctions - major A roads, motorways, that kind of thing.

I too watched a lot of tesla driver before getting the car. His videos are definitely 'don't try this at home' stuff. Stick to the boring cases and it'll be fine.

 

[drewpost]

I've had Adaptive Cruise Control (TACC) on my last three cars (Skoda Octavia, Skoda Superb and VW Tiguan). I used it when driving about 95% of the time on all kinds of roads and am very familiar with its strengths and weaknesses in non-Tesla cars.

I'm finding that I'm using it less on the Model 3 for a couple of reasons:

1 - I think it's slightly less efficient from an energy consumption perspective when driving on non M-Way or dual carriageway roads vs driving with the pedal. I'm able to create periods of regens or neutral consumption in a lot of areas where TACC doesn't. I have the choice of driving efficiently or using TACC which is fine.

2 - As far as I can tell, there's no way to have it fixed to a persistent speed, ie I set it to 55, deactivate and, unless I've turned it all the way off, when I start it up again it will be at that same speed. If you don't have it engaged, the TACC will set to whatever the speed limit is (+ a relative amount that I set). In theory, that's brilliant however owing to the absolute shitte nature of the speed limit database, I am frequently having to knock it down from 60-40. It also won't read the speed limit signs on gantries or the side of the road so all you're relying on is an inaccurate database. (my Tiguan would read the road signs and display the ACTUAL speed limit wherever I was at - I really really miss this).

3 - Inconsistent behaviour at changes in speed. I find in TACC, I've never had the TACC upper speed limit change based on what's occurring on the road. ie going 30, it changes to 40 but the car stays at 30. In AP, I sometimes have it change but it's not consistent behaviour.

4 - (this isn't just applicable to the M3) As we all know, the speed limit signs mean that, from that point forward, you're meant to be going that speed limit. However, even when AP does change down from a high speed limit to a lower one, it starts AFTER passing the sign and it does it pretty aggressively too. It would be nice if it knew there was an upcoming change and started to comfortably slow you down a configurable distance before the change.



In terms of Autopilot, I've found it works well on all motorways and dual carriageways I've been on. It's also acceptable on A and some B roads. It does NOT cope with cyclists or cars parked on the side of the road that make you straddle a lane to get past (which is behaviour I would expect given the level of maturity).

As I've been driving with TACC for 7 years now, I'm used to not being complacent and ready to anticipate where I will need to take over. Of course YMMV but it's a feature I wouldn't live without and I'm pleased, for the most part, with it on the M3.

 

[Saghost]

The logic for S and X is more complicated than that, taking into account your current speed and your speed warning offset as well as the speed limit; I don't know if the 3 uses the same logic, but I would expect it to.

With my X, once you get above 18 mph it will set to your current speed until you get within about twenty mph of the speed limit.

Then it'll set to the speed limit modified by the speed limit warning offset until you're going faster than that, at which point it goes back to setting to your current speed.

 

[drewpost]

The logic for S and X is more complicated than that, taking into account your current speed and your speed warning offset as well as the speed limit; I don't know if the 3 uses the same logic, but I would expect it to.

With my X, once you get above 18 mph it will set to your current speed until you get within about twenty mph of the speed limit.

Then it'll set to the speed limit modified by the speed limit warning offset until you're going faster than that, at which point it goes back to setting to your current speed.

I'm in a pre-facelift S loaner right now whilst they sort an audio issue in my 3 and I agree that it's totally different behaviour. It took me a little bit to get used to. It's more in line with my pre-M3 experience. Perhaps, in a UX compensation for a lack of physical controls, they "simplified" the process in the 3?

 

[Saghost]

I've had Adaptive Cruise Control (TACC) on my last three cars (Skoda Octavia, Skoda Superb and VW Tiguan). I used it when driving about 95% of the time on all kinds of roads and am very familiar with its strengths and weaknesses in non-Tesla cars.

I'm finding that I'm using it less on the Model 3 for a couple of reasons:

1 - I think it's slightly less efficient from an energy consumption perspective when driving on non M-Way or dual carriageway roads vs driving with the pedal. I'm able to create periods of regens or neutral consumption in a lot of areas where TACC doesn't. I have the choice of driving efficiently or using TACC which is fine.

2 - As far as I can tell, there's no way to have it fixed to a persistent speed, ie I set it to 55, deactivate and, unless I've turned it all the way off, when I start it up again it will be at that same speed. If you don't have it engaged, the TACC will set to whatever the speed limit is (+ a relative amount that I set). In theory, that's brilliant however owing to the absolute shitte nature of the speed limit database, I am frequently having to knock it down from 60-40. It also won't read the speed limit signs on gantries or the side of the road so all you're have is an inaccurate database. (my Tiguan would read the road signs and display the ACTUAL speed limit wherever I was at - I really really miss this).

3 - Inconsistent behaviour at changes in speed. I find in TACC, I've never had the TACC upper speed limit change based on what's occurring on the road. ie going 30, it changes to 40 but the car stays at 30. In AP, I sometimes have it change but it's not consistent behaviour.

4 - (this isn't just applicable to the M3) As we all know, the speed limit signs mean that, from that point forward, you're meant to be going that speed limit. However, even when AP does change down from a high speed limit to a lower one, it starts AFTER passing the sign and it does it pretty aggressively too. It would be nice if it knew there was an upcoming change and started to comfortably slow you down a configurable distance before the change.



In terms of Autopilot, I've found it works well on all motorways and dual carriageways I've been on. It's also acceptable on A and some B roads. It does NOT cope with cyclists or cars parked on the side of the road that make you straddle a lane to get past (which is behaviour I would expect given the level of maturity).

As I've been driving with TACC for 7 years now, I'm used to not being complacent and ready to anticipate where I will need to take over. Of course YMMV but it's a feature I wouldn't live without and I'm pleased, for the most part, with it on the M3.

For your third point, I haven't seen any inconsistency but the logic is complex.

The car will lower the speed only on roads it believes are not divided, only when it was set more than five mph over what it thinks the speed limit is, to five mph over the speed limit.

If the car was continuously in AP from a higher speed zone into a lower speed one and slowed down, it will speed back up on its own when the limit goes back up, only to the speed it was set to before. If AP was disengaged at any point, it will not.

 

[NorfolkMustard]

I'm in a pre-facelift S loaner right now whilst they sort an audio issue in my 3 and I agree that it's totally different behaviour. It took me a little bit to get used to. It's more in line with my pre-M3 experience. Perhaps, in a UX compensation for a lack of physical controls, they "simplified" the process in the 3?

they did, yeah. In M3 the double-tap just enables AP, nothing else. AP then decides the starting speed based on its navigation map/database OR the current speed you’re travelling at whichever is HIGHER

Whereas in MS/X APv1 it enables it at the speed you’re currently going at by tapping down once on the dedicated AP stalk on the left. In S/X they took the stalks from Mercedes and this works the same in mercedes with TACC too. Tap down to enable at current speed. If already enabled tapping down reduces the target speed. Tap up to increase target speed. Push away to pause, pull forward to un-pause (resume at last set speed)

 

[WarpedOne]

This debate is useless.

Go drive the car, enable TACC, monitor it and get used to it.
Then enable AP, monitor it and get used to it.

Then you will have your own answer when and where to use it.

 

[drewpost]

they did, yeah. In M3 the double-tap just enables AP, nothing else. AP then decides the starting speed based on its navigation map/database OR the current speed you’re travelling at whichever is HIGHER.

Thanks for that. This is my exact frustration. In my VW, I would set it to a speed, say 45 MPH. Then if I disengaged it, it stayed set at that speed and when I re-engaged it, it would go to that speed. In my M3, I have to re-set the speed on the incorrect limit areas which is a LOT on my routes. Driving me bonkers, especially as I use it as a tool to stay within the speed limit.

I didn't know about the forwards or backwards on the S stick though - I'll give that a play tonight. (not that it particularly matters for me as I hope to be back in my 3 soon)

 

[NorfolkMustard]

Manual says you can pause in M3 by nudging gear lever up or pressing brake pedal. And resume by pulling down again. Says that it will resume at current driving speed (rather than any other gps etc target speeds or even the previously set target speed before pausing) is that your experience too?

 

[ElectricJoules]

When using TACC the car will brake to a halt if there is a parked car in the road, even when there is sufficient space to go round it. A useful tip I've found is just to lightly apply the accelerator when you see this situation arising. Once past the parked car take your foot off the accelerator.
When the accelerator is pressed and the TACC active, the car will not brake (and it warns you so).