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AP1 Model S crossed yellow line during lane merge

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phaduman

Member
Supporting Member
Sep 16, 2016
386
576
San Jose
While driving down on CA-1 to Monterey yesterday 5PM, when left lane merged to right (reducing from 3 lane to 2 lanes), my car (autopilot engaged) couldn't follow the left yellow line (when the right side white lane divider disappeared for a while, the car has always followed the left yellow line to stay in the lane) and crossed it. I was watching closely (as everyone should) and gently nudged the steering wheel to get back into lane without disengaging AP. There were passengers taking nap and disengaging usually causes jerky movement that can wake them up. The car complied with the gentle steering pressure and didn't resist too much. I think if I had not taken action, I could have gone into the grassy left areas.

What could be the reason for this AP1 failing to follow the well marked yellow lane marking in the absence of the other lane marking? Running the latest 8.1 firmware for AP1. the sun was on the right (ocean side) and I was driving south. Distance following was set to 5.
 
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I have generally noticed that it doesn't follow yellow lines as good as white lines. it doesn't matter how clear the yellow line is. On the other hand a faint dashed white line it doesn't have any trouble, but a continuous yellow line it somehow misses more often than not.

When you are on the left most lane, the white dashed lane markers to the right is what keeps it the lane, and once that disappears as in your case, it is wobbly. You did not record your dash in that video, and that would have told you the level of confidence on the yellow line at the point of merger.

What speed where you going in this video?
 
AP1 does not reliably handle disappearing lanes like that lane merge, and has no concept of yellow vs white lines (it's monochrome), and furthermore does not seem to understand ditches/grass vs road.

As far as I can tell AP1 behaved like how I would expect it too. In the future if you don't want to disengage AP, you should initiate an auto-lane-change as soon as you see the lane ending markers. Or flick the lever to disengage AP.

It's extremely dangerous to hold off on overriding Autosteer just because you're afraid of causing passengers mild discomfort. What if a car creeped next to you as you're being run off into the shoulder? Safety should be prioritized over perceived comfort difference, and I would've taken action and moved over to the non-ending lane as soon as I saw the arrows.
 
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What speed where you going in this video?
71Mph on a 65 limit. The speed is embedded on the video (bottom center). I took the clip from the dashcam (Thinkware 770), don't have camera to record the dashboard - you have a good point - I will note that going forward - AP1's ability to read yellow lines vs. white lines.

It's extremely dangerous to hold off on overriding Autosteer just because you're afraid of causing passengers mild discomfort. What if a car creeped next to you as you're being run off into the shoulder? Safety should be prioritized over perceived comfort difference, and I would've taken action and moved over to the non-ending lane as soon as I saw the arrows.

Point taken. The traffic was light on both front, back and sides. the car was crossing the yellow line rather gently - and reacted positively to my steering control. If it was not going to, I would have yanked it hard (yes, safety first - I have done those maneuvers before too).
 
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While the camera sensor is Monochrome it's likely more sensitive to white because of what white is.

White is everything, and yellow is well not everything. :)

Now without seeing the IC it's hard to say whether it was a detection issue or if it's intentionally designed to follow the right line while in the left lane.
 
Count your blessing!

At least there were no yellow barrier:

Tesla crashes into concrete barrier!

But I do appreciate your experience and thanks for sharing.

I was thinking about that video too. My experience with AP1 in construction zones is that it deeply wanted to believe in its prior knowledge map even when the world is dramatically different. I-5 had some construction zones where they diverted all of traffic onto the other side and despite a row of cones, a Road Closed sign, and multiple parked construction trucks, AP1 would consistently follow the erased lane line grooves instead of the newly painted shifted lane lines to the other side.
 
I commute that same section every freakin work day, and that Monday morning when they out of the blue shifted the lanes with that new concrete barrier, it took me by total surprise. Luckily for me the traffic was heavy and moving at around 25 mph and i was following another car, so my AP1 car perfectly swerved to follow the new lanes, but it sure shook me up because I couldn't see the lane shifting with a car so close in front of me.

In the case of that video obviously with much higher speeds - I am guessing 45mph+ - AP1 couldn't handle it. And that shouldn't be a surprise to anyone.

One thing though - i was damn lucky to be going at a low speed that day. Another 10 mph more I would have ended with the same fate.
 
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I commute that same section every freakin work day, and that Monday morning when they out of the blue shifted the lanes with that new concrete barrier, it took me by total surprise. Luckily for me the traffic was heavy and moving at around 25 mph and i was following another car, so my AP1 car perfectly swerved to follow the new lanes, but it sure shook me up because I couldn't see the lane shifting with a car so close in front of me.

In the case of that video obviously with much higher speeds - I am guessing 45mph+ - AP1 couldn't handle it. And that shouldn't be a surprise to anyone.

One thing though - i was damn lucky to be going at a low speed that day. Another 10 mph more I would have ended with the same fate.


It's really the perfect cautionary tale for why even with AP1 so much more "stable" than AP2, why you STILL cannot let your attention off the road any longer with AP1 than you can with AP2... Things go from looking peachy to being an accident in like 2 seconds. Any amount of distracted AP supervision would've led you to the same fate. And that I don't believe can be fixed by a mapping crew combined with AP1-like hardware. It'll either need LIDAR that scans that low or a much more advanced vision processing system than is available today.
 
Agreed. In fact it is the familiarity of that route - I know every inch of it - is a catalyst for accident when there is a sudden lane change with no warnings. Since that whole section of around 4 miles is a construction zone, there is no reason to use AP
 
Knowing that accidents wi
What firmware version are you on? Because AP1 in my car doesn't let me nudge it one centimeter without disengaging. Any attempt to nudge or direct the car the tiniest bit left or right results in disengagement.
17.14.23, v8.1. Loaded on April 13.
In most of my previous experiences it would indeed be disengaged. But I have also had occurrences where I have moved the car slightly to my left when a motorcycle is about to cross me on my right side while lane sharing, and maintain autosteer. Perhaps 3 out of 4 times, AP would disengage, but not always.
 
I have generally noticed that it doesn't follow yellow lines as good as white lines. it doesn't matter how clear the yellow line is. On the other hand a faint dashed white line it doesn't have any trouble, but a continuous yellow line it somehow misses more often than not.

When you are on the left most lane, the white dashed lane markers to the right is what keeps it the lane, and once that disappears as in your case, it is wobbly. You did not record your dash in that video, and that would have told you the level of confidence on the yellow line at the point of merger.

What speed where you going in this video?

I can confirm, it doesn't follow yellow line (means construction/work in Europe) and I alway disengage the AP to prevent any trouble.(17.14.23)
 
Knowing that accidents wi

17.14.23, v8.1. Loaded on April 13.
In most of my previous experiences it would indeed be disengaged. But I have also had occurrences where I have moved the car slightly to my left when a motorcycle is about to cross me on my right side while lane sharing, and maintain autosteer. Perhaps 3 out of 4 times, AP would disengage, but not always.

BTW, @HankLloydRight can try this:
Put gentle and sustained pressure (< 4 lbs, per this article - table at the end - likely force required to disengage autosteer in Tesla) on either left or right spoke of the steering wheel using just a finger, and notice that the car changes direction slightly. The slower the car, the longer the time it takes to notice the slight change in direction. It would be interesting to see if the autosteer allows this slight change in direction to continue beyond lane boundaries without disengaging.
 
AP1 does not reliably handle disappearing lanes like that lane merge, and has no concept of yellow vs white lines (it's monochrome), and furthermore does not seem to understand ditches/grass vs road.

As far as I can tell AP1 behaved like how I would expect it too. In the future if you don't want to disengage AP, you should initiate an auto-lane-change as soon as you see the lane ending markers. Or flick the lever to disengage AP.

It's extremely dangerous to hold off on overriding Autosteer just because you're afraid of causing passengers mild discomfort. What if a car creeped next to you as you're being run off into the shoulder? Safety should be prioritized over perceived comfort difference, and I would've taken action and moved over to the non-ending lane as soon as I saw the arrows.
Oh come off it man - he doesn't need your lecture. You're not the safety czar. He posted the video to show a flaw and I agree with him. You weren't in the car - you've no idea whether his decision was safe or not.
 
It's really the perfect cautionary tale for why even with AP1 so much more "stable" than AP2, why you STILL cannot let your attention off the road any longer with AP1 than you can with AP2... Things go from looking peachy to being an accident in like 2 seconds. Any amount of distracted AP supervision would've led you to the same fate. And that I don't believe can be fixed by a mapping crew combined with AP1-like hardware. It'll either need LIDAR that scans that low or a much more advanced vision processing system than is available today.
No. It doesn't need lidar and it doesn't need a much more advanced vision processing system than is available today - I have AP2 and AP1. AP2 handles disappearing lanes without going off the road. AP1 does what the OP showed it doing - it's done it to me multiple times. Why is this? I've no idea.
 
BTW, @HankLloydRight can try this:
Put gentle and sustained pressure (< 4 lbs, per this article - table at the end - likely force required to disengage autosteer in Tesla) on either left or right spoke of the steering wheel using just a finger, and notice that the car changes direction slightly. The slower the car, the longer the time it takes to notice the slight change in direction. It would be interesting to see if the autosteer allows this slight change in direction to continue beyond lane boundaries without disengaging.

Believe me, I've tried everything to get it to nudge over a few inches when passing people while AP is engaged. As I increase pressure on the steering wheel, the car does not move one millimeter, until I get to the point of disengagement, which isn't much. Even with sustained pressure just below that point, car does not move. It's extremely frustrating, especially since people report that earlier versions of AP1 did allow such nudging or adjustments.