# Navigate on Autopilot Phantom Lane / HOV bug



## oey192 (Sep 1, 2017)

Ever since the Christmas 2020 update, I've encountered a debilitating NoA bug any time an HOV lane is present. The bug is 100% reproducible when an HOV lane is present and even crops up occasionally when there's no HOV lane. And when I say 100% reproducible I mean 100% reproducible. It has showed up Every. Single. Time I've used NoA when HOV lanes were present since late Dec 2020 and that includes a good 6 extra trips explicitly trying to reproduce the issue for Tesla service so they could pull logs (despite reproducing every time, they never got any logs that helped them because the car doesn't produce any errors along with the bug). No updates since the Christmas 2020 update have made the issue any less pervasive and Tesla service tells me that my NoA is "working as expected" despite being able to reproduce the bug.

My settings are as follows:
- "Use HOV lanes" is Off in navigation settings
- "Exit passing lane" is typically On, but the bug reproduces just as well when turned Off
- Lane change aggressiveness set to Mad Max
- Confirm lane changes is typically Off, but the bug reproduces just as well when turned On (and behavior is the same if you actually confirm all lane changes when it's safe to do so)

Reproducing the bug goes like this:

Enable Autopilot / NoA just after getting on the highway (i.e. while you're still in the rightmost lane)
Wait for the car to make 1 - 2 lane changes to the left
Observe on the center screen that a phantom lane has appeared off to the right side of the real rightmost lane
Wait for the car to use the leftmost non-HOV lane to pass a slow car in front of you
Keep waiting until you near your exit
Observe that the car gets over too soon - as if it thinks it's one lane farther left than it really is
Observe that once you reach the real rightmost lane, the phantom lane off to the right side of the highway disappears (despite earlier having had the animation indicating "I'm going to need to get in this lane in a bit" displayed over that lane)
Take your exit, never having used the leftmost non-HOV lane to pass anyone despite having a higher set speed than the traffic you were behind and multiple opportunities to use the passing lane
Every once in awhile - especially if there are only 3 non-HOV lanes total - the phantom lane won't show up until you're in the leftmost of the 3 non-HOV lanes, so the car will actually change into the leftmost non-HOV lane. Every time it does this, the phantom lane appears almost immediately and within 10 seconds the car "frantically" (I'm dramaticising here) tries to get out of what it now thinks is the HOV lane by initiating a "changing lanes to follow route".

Alternate reproduction steps:

Get into the leftmost non-HOV lane (the phantom lane off to the right side of the road will be displayed on the center screen
Turn on Autopilot (while NoA is enabled / there is a GPS destination)
Within a few seconds, a "changing lane to follow route" notification appears and the car quickly tries to get out of the passing lane. (Note that it definitely does NOT say "changing lane to exit passing lane".) Tapping on the screen to cancel results in only a very brief pause before it tries again. You have to consistently cancel the lane change to prevent it from getting over

If you repeat the Alternate reproduction steps above while "Use HOV lanes" is On in navigation settings, the bad behavior does not appear, but instead the car now treats the non-HOV lane that you're in as the HOV lane and won't exit it once it's done passing cars. Also, it will venture into the actual HOV lane if there's a split between the main highway and the HOV lane (e.g. when a bridge pillar separates the two). This prevents this from being a "workaround" for this bug as you can't tell the car that it can use the HOV lanes unless it actually can use them.

A remote Tesla technician and the local Tesla service center claim that just because the car is displaying a lane off to the right side of the road doesn't mean that the car actually thinks there's another lane there (that doesn't exist in reality), but I call BS on that at least in this case as I'm positive the car does think there's an extra lane off to the right side of the road and it's using that to determine which lane is the HOV lane. However, since it's incorrectly seeing a lane off to the right side of the road that doesn't exist, it also thinks the HOV lane is one lane farther to the right than it really is and therefore refuses to be in that lane. Prior to the Christmas 2020 update, I had observed this "changing lane to follow route" behavior when enabling NoA in the actual HOV lane when forgetting to enable the HOV option in the nav settings (I used to carpool a lot before the pandemic and would forget to switch the option on Monday mornings after driving by myself on the weekends).

After 7 months of this bug not getting fixed, I finally got fed up and scheduled a service appointment for it. After some remote debugging which didn't help at all, I took the car in and Tesla Service claims that they were able to reproduce the bug (which I don't doubt). However, they also claimed that NoA is "working as expected" on my car and that "right now, the car just wants to stay in the middle lane. Eventually this should get fixed by an update". I really wanted to show someone the bug in action and see if they could look me in the face and tell me that this is intended functionality - and that it's not a regression (because it absolutely is a regression) - but due to COVID they aren't doing ride-alongs.

Thankfully the bug doesn't cause the car to do anything unsafe, but it makes NoA completely unusable for me. If I wanted to sit in the slow lane and never pass anyone, I wouldn't have paid for FSD. Regular AP works just fine of course, but the flagship EAP/FSD feature that for me was legitimately useful from ~Aug 2018 until Dec 2020 has now been unusable for 8 months. That's ~22% of the time the feature has been available. Can I get a 22% refund on what I paid for EAP? (rhetorical question)
I know they're all heads down working on FSD Beta right now, but this is a production feature that used to work really well most of the time and now it's essentially useless. I get that everyone in California won't care about this bug because they can always use the HOV lane which means they probably haven't even noticed it's a thing, but for the rest of us, this bug is a really big deal. Was I the only person outside of CA who used NoA before Dec 2020? (If so I assume now no one outside CA uses NoA at all)

So, some questions:

Has anyone else encountered this bug? (Especially between Dec 2020 and now)
Should I schedule another service appointment to get this looked at again? (The car was on 2021.4.x when Tesla Service looked at it last time and now it's on 2021.24.3)
If no one else has encountered this bug, and if I shouldn't schedule another service appointment, how do I help Tesla fix this bug? (If I'm one of the few people experiencing this bug I don't expect that the rewrite is going to magically fix it once us peasants get FSD Beta)

P.S. / EDIT: We have a Model Y as well but that car is still on 2020.48.10 (pre-Christmas 2020 update) specifically in case it would experience this bug if we updated it. I have tested several times on the same roads that the Model 3 exhibits the bug 100% of the time and the Model Y works as one would hope it would (i.e. no bug). I really don't want to update the Model Y in case it runs into this bug, hence why I was hoping to get a read on other Tesla owners as to whether this is a common bug or not)


----------



## PalmtreesCalling (Apr 22, 2019)

You would make a GREAT tester. Lots of attention to detail


----------



## FRC (Aug 4, 2018)

I can't say that I've noticed your "phantom right-most lane". But I rarely use NOA due to it's general "buggy behavior". When I do use NOA, I ALWAYS use lane confirmation since NOA is terrible at imitating an actual driver when making lane changes. I believe that NOA will improve over time(how much time is anyone's guess). In the meantime, I find NOA useful only when navigating unfamiliar interstate interchanges. Thus, this is the only situation for which I use NOA and then only with lane confirmation on. I suggest adopting a similar approach while we wait for future improvements. IHMO, trying to get Tesla service to address these bugs on a case-by-case basis is akin to tilting at windmills.


----------



## JasonF (Oct 26, 2018)

It sound to me like the map data is incorrect, and that AP is trying to resolve map data that says the road should have one additional lane vs actual data that it does not. So perhaps the conclusion AP is coming to is that either the rightmost or leftmost lane is under construction, and then it follows its usual protocol for that - to avoid it and go to the safer center lane.


----------



## oey192 (Sep 1, 2017)

FRC said:


> I can't say that I've noticed your "phantom right-most lane". But I rarely use NOA due to it's general "buggy behavior". When I do use NOA, I ALWAYS use lane confirmation since NOA is terrible at imitating an actual driver when making lane changes. I believe that NOA will improve over time(how much time is anyone's guess). In the meantime, I find NOA useful only when navigating unfamiliar interstate interchanges. Thus, this is the only situation for which I use NOA and then only with lane confirmation on. I suggest adopting a similar approach while we wait for future improvements. IHMO, trying to get Tesla service to address these bugs on a case-by-case basis is akin to tilting at windmills.


I used NOA all the time prior to the Christmas 2020 update with confirmation off. There were certainly a few times here and there where I had to manually initiate a lane change or cancel a poorly timed one, but most of the time it worked well. I could go dozens of miles without a disengagement as long as no construction was involved. Since the Christmas 2020 update it's been complete garbage (I don't even want to use it with confirmation on it's so bad) due to the bug I've described above.

I took it in for service in the hopes that they could help HQ fix the bug since apparently the in-car bug report function doesn't do this. I've reported this bug a good 10-15 times at this point and no dice



JasonF said:


> It sound to me like the map data is incorrect, and that AP is trying to resolve map data that says the road should have one additional lane vs actual data that it does not. So perhaps the conclusion AP is coming to is that either the rightmost or leftmost lane is under construction, and then it follows its usual protocol for that - to avoid it and go to the safer center lane.


Hmmmm. I hadn't considered that the map data might be wrong. I think that isn't the issue, but I will have to go confirm next time I go for a drive. If, when I'm in the rightmost lane, I see a phantom lane off to the left then I would concede that the map data is wrong and it says there's one more lane than there really is. I don't think that's it due to how many places I've run into the issue, but it is possible. Not sure why a map update would start showing more lanes than actually exist when there's been no construction in the area that would add lanes (and no such construction is ongoing)


----------



## JasonF (Oct 26, 2018)

oey192 said:


> Not sure why a map update would start showing more lanes than actually exist when there's been no construction in the area that would add lanes (and no such construction is ongoing)


It wouldn't be an added lane so much as a lane _shift_ that would cause that behavior. If it thinks the shoulder is now a travel lane due construction, for instance.


----------



## oey192 (Sep 1, 2017)

JasonF said:


> It wouldn't be an added lane so much as a lane _shift_ that would cause that behavior. If it thinks the shoulder is now a travel lane due construction, for instance.


Hmmmm. Definitely not construction that's causing it. The bug will persist for miles where there's no construction at all. Sometimes it detects those thin vertical poles with reflectors on them and displays them as a barrier between the real road and the extra lane that it sees (but still indicates that it eventually wants to get into that lane if it needs to take an exit kinda soon).

But the bug also very definitely also shows up when no such reflector poles are present


----------



## JasonF (Oct 26, 2018)

oey192 said:


> Hmmmm. Definitely not construction that's causing it. The bug will persist for miles where there's no construction at all. Sometimes it detects those thin vertical poles with reflectors on them and displays them as a barrier between the real road and the extra lane that it sees (but still indicates that it eventually wants to get into that lane if it needs to take an exit kinda soon).
> 
> But the bug also very definitely also shows up when no such reflector poles are present


I mean whatever map data it's getting thinks the road is under construction for some reason. Maybe it was at one point and no one bothered to update the map after it was done?

And yes, that is ridiculous. But so is the fact that the ramps around the ESPN complex here were finished 3 years ago, but Autopilot still jams on the brakes because it thinks the construction speed of 35 mph is still active.


----------



## Long Ranger (Jun 1, 2018)

oey192 said:


> Has anyone else encountered this bug? (Especially between Dec 2020 and now)


I've seen this bug, but it was in the early days of NOA lane change. Didn't test it as thoroughly as you, but I definitely concluded that the car was mistaking the left lane for the HOV lane. Saw it repeatedly on 405 north of Bellevue.

I'm surprised that you found NOA lane change to be useful. Seemed like lane changes got better, but never to the point that I would consider using it regularly. And I'm still on pre-Christmas software.

Also, I recall how the car's panic to get out of the left lane was annoying, but I don't quite understand why the failure to move into the left lane is a big problem for you. Just turn on your left turn signal. I do that all the time when on either AP or NOA. For me, I find turn-signal initiated auto lane change much more satisfying than random car initiated ones. But even if you like the car initiated ones, it's pretty easy to supplement those with the turn signal.


----------



## oey192 (Sep 1, 2017)

JasonF said:


> I mean whatever map data it's getting thinks the road is under construction for some reason. Maybe it was at one point and no one bothered to update the map after it was done?
> 
> And yes, that is ridiculous. But so is the fact that the ramps around the ESPN complex here were finished 3 years ago, but Autopilot still jams on the brakes because it thinks the construction speed of 35 mph is still active.


I've seen this bug on bits of road that have not been under construction for years before NoA ever launched. And not sure why a map update would suddenly remember previous construction when it hadn't known about it before…

But yeah, I've experienced many construction related issues with NoA. I-5 in Tacoma is particularly egregious. NoA has never worked properly through there during any trip I've taken since NoA launched (sometimes it has managed the north- OR south-bound direction fine, but never both at the same time (within a 2 day period)

This particular bug does not appear to have anything to do with any particular section of road or construction and it is an obvious regression from pre-Christmas-2020 behavior


----------



## oey192 (Sep 1, 2017)

Long Ranger said:


> I've seen this bug, but it was in the early days of NOA lane change. Didn't test it as thoroughly as you, but I definitely concluded that the car was mistaking the left lane for the HOV lane. Saw it repeatedly on 405 north of Bellevue.
> 
> I'm surprised that you found NOA lane change to be useful. Seemed like lane changes got better, but never to the point that I would consider using it regularly. And I'm still on pre-Christmas software.
> 
> Also, I recall how the car's panic to get out of the left lane was annoying, but I don't quite understand why the failure to move into the left lane is a big problem for you. Just turn on your left turn signal. I do that all the time when on either AP or NOA. For me, I find turn-signal initiated auto lane change much more satisfying than random car initiated ones. But even if you like the car initiated ones, it's pretty easy to supplement those with the turn signal.


Sure, I can use my turn signal to get around the fact that it won't get into that lane by itself, but since it always - and I mean always - tries to get right back out of the lane, what's the point?
If I'm going to need to initiate lane changes myself anyway, why should I even bother to enable NoA in the first place?

That's my point. NoA was useful (at least for me) before this bug was introduced. I could occasionally make 60-70 mile drives with 0 interventions and often with only 1-2 interventions. Now I can't even go 500 feet without having to intervene and at that point I'm intervening constantly for miles (unless I turn the feature off), making it thoroughly useless

Interesting that you saw this bug awhile ago. Mind you I haven't used NoA on 405 a lot, but I've never experienced this bug ever on I-5, 405, or elsewhere prior to the Dec 2020 update. Now it's 100% reproducible everywhere


----------



## oey192 (Sep 1, 2017)

Well just thought I’d pop in to say this bug is still here nearly 1.75 years after being introduced. 100% reproducible in every Tesla I’ve tried it in (multiple Model Y and Model 3 vehicles

Back in April I finally got a ride along with a technician and they submitted a report to Tesla engineering about this bug. Maybe if they ever solve FSD they’ll get around to fixing this bug after that?

Super dumb to have this bad and this easily reproducible bug in production for so long. No other major company could get away with this. How can Tesla?


----------



## evannole (Jun 18, 2018)

I have had a somewhat similar issue with NOA for years now.

I have "Use HOV Lanes" enabled. When I drive in them with NOA turned on, it wants me to exit them, into the leftmost non-HOV lane, as soon as the lines go from double-solid to double-dashed, even though I won't be exiting the interstate for 15 miles or more. It's as if it thinks that the HOV lane is actually the passing lane.

I gave up on using NOA years ago, largely because of this, along with the fact that the Tesla navigation system still doesn't understand or utilize the reversible toll lanes we've had in Atlanta for nearly four years now. Waze had them figured out - when they were open, and in which direction - almost immediately upon opening, but Tesla has done nothing with them, though the system does understand that they exist once you're on them, as it correctly knows where the exits from the lanes are (onto roads that do not have exits from the non-toll part of I-75).

How they'll ever achieve real FSD without first improving the navigation system to cover issues like these is a mystery to me.


----------



## Klaus-rf (Mar 6, 2019)

evannole said:


> How they'll ever achieve real FSD without first improving the navigation system to cover issues like these is a mystery to me.


 It's definitely a complex issue. Bad mapping is just one small part of the solution.


----------

