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Where the Autopilot Doesn't Work (List)

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I get tremendous use out of the autopilot. It's a fantastic feature. I do a lot of long solo driving and now I get home happy and calm, instead of mentally exhausted.

But there are characteristic situations where it doesn't work well. Things to watch out for. Things I wish someone had told me before I had to learn them for myself. Some of these are things we "ought to know" (because, for example, they happen only on 2-lane roads where we "aren't supposed to be using the autopilot" but many do regardless) while others are less obvious. Here's a short list, in the hope of contributing to safe and happy semi-autonomous driving.


  1. Right lane on roads with exits - autopilot is prone to follow fog line off exit rather than lane divider line.
  2. Intersections - even with no traffic, even just roads entering from the side, or forks: various problems, including a form of the above (autopilot follows fog line partway through right turn when center line stops)
  3. Next to hard dividers (Jersey barriers): watch out for the left lane on these roads, the autopilot will creep right and crowd other drivers in the center lane (or worse). In general, the AP seems to try much too hard to avoid fixed obstacles and cannot maintain proper lane position when next to them.
  4. Terrain angle changes, particularly next to hard dividers: hilltops or sudden bumps in the road can trick the autopilot into veering from the right or left lane into the center lane.
  5. Autopilot doesn't know the difference between double yellow lines and dashed lines, so: watch that left turn! On 2-lane roads, if you carelessly leave the autopilot engaged while following another vehicle at low speed, then signal a left before hitting the brake, the autopilot can "change lanes" and accelerate across the double line into oncoming traffic when what you meant to do was stop and turn.
  6. Construction zones: just turn it off when you see that orange sign. Please.
  7. Left-hand exits, splits or forks in divided highways: if you see one coming, get at least one full lane away, or turn off the autopilot; it *will* screw up.

In general, it is safest to hold to the center lane when available, I find, or the left lane if only 2 are available in the direction of travel. Of course, with the Jersey-barrier issues, that can be problematic as well -- you have to know to watch out. Driving with the autopilot has a learning curve just like any other kind of driving.

Those are the things I watch out for. I'm sure there are more -- maybe we can make a master list?
 
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I think that list is pretty complete, and I agree with all of them.

The only thing I'd add is it also messed up in the right lane with on-ramps. Basically anytime in the right lane where it loses the right line. It gets confused and feels like its "hunting".

I vastly prefer traveling in the middle lane, but sadly a lot of times there isn't a middle lane.
 
I agree with the above but want to add that most of the situations you described above have been described by Elon and Co as "no use" situations from the very beginning.

I've noticed a few things now with a few hundred autopilot miles under my belt:

1) When I am about to lose my lane the car will follow the lane that has the most predominant lane line left. So on the HOV lane when it goes away the car will track the left side of the lane until it establishes another lane line on the right. This works VERY well.

2) When I want to take an exit, like on the HOV to work we exit left to change freeways, all I have to do is hit the blinker (half-push not full click) and it actually follows the left lane into the HOV exit. I tried this on the right side with exit ramps and it appears to also work well.

3) You don't have to do a full click on the blinker stalk - if you just hold pressure in the direction you want to go it will change lanes. I like this because if I change my mined all I have to do is let go and as long as I am not more than 50% into the new lane the car will "snap back" into my lane. I love this.

4) Once you get the hang of it you can almost guess the "confidence level" the car has at any given time and even predict by looking ahead what kind of issues you might need to deal with. Anyone who has driven with AP for more than a little while should understand that the upcoming exit might be an issue, etc. It's about learning how "she behaves" and dealing with it - or preparing for it. For me it means holding the wheel a little tighter when I go over a bridge next to a semi-truck, for example.

Keep on Piloting!
 
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Same thing happens in the morning when heading into the sun. I can drive the exact same stretch of road (highway 85) at other times of the day without issues, but when the sun is hitting the road (or the windshield) at the wrong angle, the camera is unable to track lane markings and autopilot is disabled.
 
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I think the left lane on the highway is dangerous even without exits because for some reason much of the time it tries to avoid the barrier by riding the far right edge of that lane, so if anyone in the middle lane is over the line a little or close to it, I have to take over.
 
Fellow beta testers, it's interesting that the issues we experience with autopilot don't feel like defects, but rather limitations of this 1st gen technology. It really feels like we're paving the way for the future of autonomous driving. I'm sure our grandkids will get a kick about the stories we tell about the beginning of what will surely be the prevailing technology driving cars around 10 years from now. It's exciting to be in the drivers seat for a part of automotive history.
 
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My 2015 S85 goes in fit AP activation on the 16th. Honestly I'm both excited and aprehensive. The notes made in this thread are really helpful. What instruction (live and document) is given at time of picking up an AP activated S? I see someone mentioned that Elon had already noted "no use" situations. Where can I find this?
 
Cresting bridges that have temporary markings. Car goes from fine to red alert instantly. Hope you're not in a turn and cruising way to close to the car next to you. But I don't think there is much fix for that, the car does not have enough sensors to seek the correct side of the lane well.
 
I totally agree. It is so exciting to be part of a new revolutionary wave of technology, that thanks to Tesla, we get to contribute through the crowd sourced learning that they (and we) are doing. I see my car getting better every single day; learning what I teach her and what others are contributing through this learning. The incremental learning is quite obvious to me in the way that she reacts to situations that used to be baffling.

The Thomas Edison of the late 19th and early 20th has now become us. All of us, every day, as we contribute to the overall knowledge and good of transportation, are building a knowledge base never yet seen before. At one million miles per day. 1,000,000 per day. Think about that.

How incredibly exciting is that?!?

Fellow beta testers, it's interesting that the issues we experience with autopilot don't feel like defects, but rather limitations of this 1st gen technology. It really feels like we're paving the way for the future of autonomous driving. I'm sure our grandkids will get a kick about the stories we tell about the beginning of what will surely be the prevailing technology driving cars around 10 years from now. It's exciting to be in the drivers seat for a part of automotive history.
 
20151204_085930.jpg

Tunnels, its horrible in tunnels, it tries to avoid the wall and pushes you outwards into traffic (this picture taken in a tunnel with 2 lanes going my direction)

Most highways here have a center divider that is actually a physical fence/wall/whatever. If you're in the left lane (most highways are 2 lane each direction here) you also get "pushed" towards the middle. This puts you much closer to other cars than I'm comfortable with if I drive myself.
 
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Was using Autopilot yesterday on local two lane road. No opposing traffic coming so out of curiosity decided to test lane change over double yellow line. It refused to do it. My firmware is at level 2.9.12

Can confirm. Also will not go into our out of HOV lanes in AZ because they have double white lines.

- - - Updated - - -

My 2015 S85 goes in fit AP activation on the 16th. Honestly I'm both excited and aprehensive. The notes made in this thread are really helpful. What instruction (live and document) is given at time of picking up an AP activated S? I see someone mentioned that Elon had already noted "no use" situations. Where can I find this?

I didn't get any instruction on autopilot except for during a test drive and it was just how to turn it on and off.

My recommendation is to start slow. Use it only on clear, dry, highway roads to start. Then as you get more comfortable with how it behaves you can start to explore your limits as well as the limits of the system.

Best of luck and congrats!
 
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I'd rather it stayed close to the hard barrier and farther from the moving car, or at least did a better job of staying right in the middle. Several times I have had to take over when the car next to me drifted into my lane a little. it's especially bad when I'm in the drifting car's blind spot, which is when such drifting is most likely to happen, of course. I'm thinking the sensors for that area are inadequate.

(no, I never drive in blind spots intentionally, except when there's no other choice, such as heavy traffic or passing)

--Snortybartfast
 
Most freeways around here have two or three lanes in each direction. When I initially enter a freeway with three lanes, I usually take up my position in the center lane and set the autopilot. I've seen multiple instances where I try to use auto lane change and the car just refuses to do it. I'm not sure if this means that the car cannot distinguish between solid white lines or dashed white lines, or if the car doesn't realize that there is another lane there.

This has happened multiple times with the auto lane change beta. I have to override autopilot to change lanes. First world problem, I know -- but I wanted to offer this feedback.
 
I've had a couple of really scary cases where I've changed lanes and there was another vehicle in the right hand lane next to the one I was changing into, in once case a truck, the other was an ordinary sedan. In these cases, the autopilot went way too far to the right side of the lane I as going into and triggered the collision warning. I think what may have been happening was the radar and camera didn't see the adjacent car and for some reason went too far to the right until the ultrasonic sensors went off.

Another thing I've noticed that I don't like, and others have mentioned, is the way it stays too far to the right in the lane. It even shows the car icon as hugging the right side, even in the middle lane with no barrier to the left. It also seems pretty bad at mapping out curves in the road, even the very gentle ones on highways. If the road curves to the left, the tendency of the car to not follow the curve plus its proclivity for hugging the right side of the lane can position the car very close to the car in the adjacent right lane. I've seen the autopilot icon for the car in front shown as straddling the lane marker whereas what was really going on was the car in front was in the middle of the lane, but the highway was curving and the autopilot wasn't mapping the curve.

This is all on highways, on local roads, except for very slow stop and go traffic, I never use autopilot, it's far too incompetent in my opinion.
 
On the same stretch of expressway I travel daily I have noticed a strange occurrence. Before Day-Light savings time and trees still had some leaves I had no problem with autopilot holding true and straight and locked on target. Since I am leaving an hour later in the morning now (daylight savings time) and the trees have dropped all of their leaves, the sun coming through the tree lines on the side of the road cause the continual change of shadow, direct sunlight, shadow, direct sunlight and it confuses autopilot. It never gives up or even give the "hold steering wheel" message just gets a little squirrely, stays well within the lanes, but does constantly veer a little back and forth.
 
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Good list, for autosteering - a subset of autopilot. I'd add that my biggest dissapointment is with the autoparking functionality part of autopilot. I've tried a ton of times to get it to appear since release and nada, nothing, and it would totally be useful here in Chicago at times. It was so reliable and dependable on our Range Rover and even Toyota in the past - yet hasn't even showed up or isn't easy to use apparently on the Tesla :-(
 
On the same stretch of expressway I travel daily I have noticed a strange occurrence. Before Day-Light savings time and trees still had some leaves I had no problem with autopilot holding true and straight and locked on target. Since I am leaving an hour later in the morning now (daylight savings time) and the trees have dropped all of their leaves, the sun coming through the tree lines on the side of the road cause the continual change of shadow, direct sunlight, shadow, direct sunlight and it confuses autopilot. It never gives up or even give the "hold steering wheel" message just gets a little squirrely, stays well within the lanes, but does constantly veer a little back and forth.
I've noticed the same thing. What I have called "stripy tree shadows" in other posts in other threads really throw AP off. It hunts side to side as you say, but it also fails in spots (e.g. right exit lane on a leftward curve) where it used to work.