# Autosteer Vehicle Over the Line Threshold



## mt09 (Oct 25, 2018)

I'd like to get a better understanding of the conditions and actions Autopilot/Autosteer will take when a vehicle in an adjacent lane is near or over the line. In all cases I've experienced, AP will hold the center of the lane regardless. The closest call where I didn't take over was when a semi's outside tire was over the line and AP did not veer from it's center path. Felt like it was inches away, way too close for comfort. Most of the time I'll move the wheel to disengage, pass the vehicle, then reengage. Unfortunately my commute is riddled with drivers like this. From what I've noticed with vehicles changing lanes, AP won't consider it as "in the lane" until they're more than 50% "in the lane." It's a little jerky right now when you see the car start to change lanes and AP doesn't see it until this threshold then rapidly slows down to maintain following distance. If there's no one behind me I'll let it go but otherwise I'll disengage to make it a little more smooth. I've noticed though it's getting better with vehicles merging from a ramp by slowing down preemptively to give room. But back to the "over the line" case, I'm guessing the current conditions are hold center of lane until "collision threshold" then slow and move to avoid collision? It doesn't seem like there is any middle ground where it'll move and hug one side of the lane. I don't think that's the right logic either cause it's just a cascading effect. What are your thoughts and experiences. How close have you let it get?


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## jdcollins5 (Oct 31, 2018)

The current AutoSteer programming is for center of the lane. If someone gets too close I lift the stalk with foot on the accelerator for a smooth transition and move to the other side of the lane.


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## Ed Post (Sep 18, 2018)

It seems the criterion the autopilot uses is something like encroaching half-way, both for moving and stationary cars. I've watched it carefully when a car changes lanes in front of me with low clearance. It seems to suddenly notice the car about half-way through the maneuver.


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## Kizzy (Jul 25, 2016)

What I've noticed is that Autopilot will only respond if the car is more or less adjacent—it will shift slightly, but not enough for comfort.

I've had one occasion when Autopilot was not engaged and it made a rapid shift in the lane to avoid a possible side collision with another car.


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## BMP (Dec 25, 2018)

Have had the same experience with semis - on Monday a truck was pretty clearly drifting over the line in my lane as I passed on the left, and just too close for comfort so I disengaged so I could ride the left line as much as needed.


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## JoeP (Sep 7, 2018)

Yes i didnt realize how dynamic *I* was in lane position until i started using EAP where its nailed to the center of the lane all the time. It initially caused me to disengage a lot becuase i felt uncomfortable how close i was to traffic. However i think i'm an outlier (looking at what i used to do: i would ride the left side of the lane as long as their wasnt traffic, and then rapidly move to the right as i got into traffic, especially opposing traffic on 2 lane roads which is what i mostly drive on). EAP does none of that. I do notice that recent versions will get closer to the center line on winding roads now though than earlier versions, approximating what a human drive often does.


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## Climate Change Denier (Jan 2, 2019)

I just had an alarming case where the autopilot did not do anything about an extremely dangerous merge. The car was crazy close as it threaded a gap between a car I was overtaking and me. I'm quite sure that the autopilot didn't do anything (or if it did, it was essentially co-incident with my manual input).

Unfortunately, while I am saving the teslacam, this occurred during the rollover from one minute to the next, so the critical second or so between the car first appearing in the (narrow) camera view and time I applied manual input is lost. I didn't really notice the discontinuity during rollover before now (sigh). You can see below the last frame before the gap (you can see the edge of the grey car in the next lane just peeking over the white car above and to the right of the mirror). At this point the tesla is dead center in the lane. For the next frame I have captured, you can see the result of my move with the car now fully in front of me.


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## garsh (Apr 4, 2016)

Climate Change Denier said:


> I just had an alarming case where the autopilot did not do anything about an extremely dangerous merge. The car was crazy close as it threaded a gap between a car I was overtaking and me. I'm quite sure that the autopilot didn't do anything (or if it did, it was essentially co-incident with my manual input).


My guess here is that even though the car was stupidly close, it was actually completely in front of you and going faster than you. I've noticed that autopilot never seems to do anything if a car is completely in front of you AND is driving at least 1-2 mph faster than you. It won't warn, and it won't brake. It's a different reaction than a human would have, but it's probably ok to do nothing if that's the case.

One time, I had a truck passing me at about 1 mph faster than me, and then decide to merge to the right in front of me. It wasn't terribly close, but it was closer than what I had my autopilot following distance set to at the time. It wasn't enough of a speed difference for autopilot to be happy, so the car slammed on the brakes. Other times, I've had cars travelling at a faster differential move over even closer, and my car just maintains speed and heading.


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## Climate Change Denier (Jan 2, 2019)

As good a theory as any--I've seen stuff like that. It was definitely traveling faster than I was, but was definitely entering my lane before its rear had cleared my front.


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## No ICE (Sep 25, 2017)

Using NoA I was in the leftmost lane going around a right curve. The car was not centered but hugging the right hand side of the lane. The car I was passing in the adjacent lane began to drift into my lane. My car took no steering actions (like re-centering in it's own lane). The other car got really close when my car sounded the collision alarm (3 chimes) and braked to fall behind the other car. NoA did not disengage. When the other car moved back into it's lane, my car passed it without incident. I'm not convinced that AP will take steering actions yet to avoid collisions, just braking actions.

Does anyone have evidence that it will in fact take steering actions for collision avoidance?

This was on 2018.50.


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## RonAz (Oct 16, 2018)

Mine did it once very early on. Hasn't had the opportunity again. I was impressed, it moved partly into the empty lane on my right to protect itself.


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## ADK46 (Aug 4, 2018)

My sense is that auto-steer is simply not very sophisticated, not enough to do "lane positioning". Most of us will automatically steer within a lane to maximize the distance from potential danger, like meandering cars and big trucks. On curves, auto-steer comes close to being a meandering car itself, tending to react late and hugging the outside line when human behavior is just the opposite.

But Musk uses the term "sublime" when describing auto-steer. There does not appear to be any effort at Tesla to make auto-steer a more sophisticated driver. If we need a definition for this, it is how a good human driver steers a car, who is constantly seeking to minimize risks of collision. And doing so with graceful movements.

A related question: is the "blindspot" display showing the car's best knowledge of the position of nearby vehicles? If so, thank goodness our cars do not react to it. Does the car have better knowledge it uses for the routine operation of auto-steer? Apparently not.

Does the car's anti-collision system use better knowledge, and manage to avoid contact? I'm guessing it does, or there would be more reports here of actual contact with other cars. Programmatically, I would prefer that it share information with the auto-steer system, so that it could do a little pre-avoidance. In my imagined block diagram, there would be a module called "lane positioning" that takes this and other factors into account to make fine adjustments to the desired steering path.


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## garsh (Apr 4, 2016)

No ICE said:


> Does anyone have evidence that it will in fact take steering actions for collision avoidance?


There are several videos on YouTube where the car steers away to avoid a collision, and the owner of the car says that the car performed the steering - not themselves.

If you watch them, you'll see that the car doesn't take action unless a collision is really imminent. An adjacent car just going over the line isn't going to trigger it. The best course of action is to hit the brakes immediately, and the car always seems to do that.


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## MelindaV (Apr 2, 2016)

No ICE said:


> Using NoA I was in the leftmost lane going around a right curve. The car was not centered but hugging the right hand side of the lane. The car I was passing in the adjacent lane began to drift into my lane. My car took no steering actions (like re-centering in it's own lane). The other car got really close when my car sounded the collision alarm (3 chimes) and braked to fall behind the other car. NoA did not disengage. When the other car moved back into it's lane, my car passed it without incident. I'm not convinced that AP will take steering actions yet to avoid collisions, just braking actions.
> 
> Does anyone have evidence that it will in fact take steering actions for collision avoidance?
> 
> This was on 2018.50.


you are much more trusting (of both EAP and the adjacent car) than I am. even without an adjacent car, I overtake steering when EAP hugs the line on a curve.


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## Kizzy (Jul 25, 2016)

No ICE said:


> […]I'm not convinced that AP will take steering actions yet to avoid collisions, just braking actions.
> 
> Does anyone have evidence that it will in fact take steering actions for collision avoidance?


I don't have visual or official documentation evidence, but my car definitely took steering action (accompanied with the warning beeps) to avoid a possible side collision a couple of months back. It was a small jerk to the left.


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