# What happens when AutoPilot (software not vehicle) crashes



## eXntrc (Jan 14, 2019)

I just stumbled onto this video from about 10 days ago:






I searched the forums and maybe I missed it but I didn't see anyone talking about it. Has anyone here experienced such a crash? I'm especially curious what would happen at higher freeway speeds.

Looks like he was running v9 2018.50.6.


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## Bokonon (Apr 13, 2017)

eXntrc said:


> I just stumbled onto this video from about 10 days ago:
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The video's assumption that the autopilot software itself "crashed" seems a bit of a stretch for me. I actually think the contrary is true: Autopilot was functional the entire time, and intentionally disabled itself in response to a sudden loss of critical sensory input (most likely forward radar).

I've experienced the exact behavior shown in the video once, and it was while driving on the highway at 65 mph in wintry conditions. There came a point where enough frozen road-slush accumulated on my front bumper that Autopilot lost confidence in the radar input, prompted me to take over immediately, and disabled itself for the remainder of the trip. (It's worth noting that even though the radar was the issue, my display no longer showed any cars detected by the rear and side cameras.) Later, after exiting the vehicle and clearing the slush off the bumper, Autopilot became fully functional once again.

The only part of the video I don't understand is what would have caused the radar (or other sensor) to malfunction, since winter weather clearly wasn't an issue, he was just crawling along in traffic, and I didn't see any road debris in this particular clip. Other possible causes (e.g. loose connections, debris or other obstructions encountered prior to the start of the video) may be outside the scope of what we know from the video alone.

I'm curious what happened after the conclusion of the video. Did Autopilot resume normal operation on his subsequent drive? If not, did he call Tesla Service? What did they find out from examining the car's logs? Etc.


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## garsh (Apr 4, 2016)

I haven't had that happen.

What I have had happen multiple times is for a popup to appear. It's similar to the usual "hold steering wheel" autopilot popup, but it's red instead of the calming blue, it says something like "take over steering immediately", and it makes a sound similar to the collision warning sound. But as soon as I apply torque to the steering wheel, autopilot continues to work. Quite strange. And it doesn't coincide with the usual nagging to hold the wheel.

My best guess as to why this would happen is that the autopilot computer became starved for CPU cycles for some reason, and didn't complete it's interpretation of the surroundings in time. But, that's just a guess.


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## eXntrc (Jan 14, 2019)

I've had the "red wheel of death" alert too, but when I've had it there was usually some situation that AutoPilot had no solution for. One example is an off ramp I take that just after the exit splits into two lanes. The car is driving right down the middle and then suddenly freaks out. I think it's something about the way the lines are painted. There were other instances when it happened and I remember thinking at the time "Yeah, I could see how that would be really confusing", but I don't remember what those situations were at the time. I think it's happened to me a total of 3 times so far.

Your theory about the CPU being starved for cycles is an interesting one. The user that uploaded the video also theorized that one or more of his AP cameras cut out for some reason. To me, this looks like a true hardware or software fault and it's good to see that there are "upstream" systems that handle the situation. I'm just curious how _well_ it's handled.

In my experience with the red wheel, the car is basically saying "You need to take over now!" Auto steer disengages and the vehicle starts to coast. My experience in those situations did not include any kind of automatic deceleration other than whatever your regen settings are already set to.


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## Kizzy (Jul 25, 2016)

I’ve had similar alerts that have caught me off guard as I hadn’t gotten any other alerts. This tends to happen at merge points when getting onto the freeway, IIRC.


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## ADK46 (Aug 4, 2018)

I would like a display of AP "confidence", or some indication that the system is struggling - not an abrupt "I'm outta here!".

I left AP on during blowing snow last week, with caution. Traction wasn't an issue, just visibility. It would get so low that I would have slowed if I were in control (I did, eventually). The blowing snow had to be reducing AP's "confidence", but there was no indication except steering got a bit jerky.

Impressive, in a way, but not the way I would have the system behave when things get dicey - it should have informed me that it was having trouble finding the lane markings, and slowed down. The software objects that pass on their findings to other modules (e.g., position within a lane, or relative speed of the car ahead) should include a value representing the quality of the information. The module that ultimately steers the car should compute an overall quality level, and use it for a range of intermediate steps before disengaging.

I know, the human is to remain alert to take over. I'm saying that the system should keep the human _informed_. Just how much fog can be tolerated? Are those faded lane markings OK? Is the car's vision system better than my old eyes, so I should leave AP engaged?


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## eXntrc (Jan 14, 2019)

I agree that a confidence level indicator would be really helpful. And I know a confidence level is there under the covers.

There's a road I regularly drive where Auto Steer will _refuse_ to engage at specific points along the route. It's always the same points and I have them all memorized now. But interestingly, if I engage Auto Steer at the beginning of the road and never disengage it, Auto Steer will stay engaged for the entire road and drive it quite skillfully. However I _know_ that when it gets to those points along the route its confidence level must be really low. It still does a good job, but I imagine these are places where it would get a lot more "freaked out" if something unexpected happens.

I would love to have more insight into the confidence level. Especially on roads I don't normally drive, since I wouldn't have the same intuition as I do about the road I mentioned above.


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## ThatRandomGuyMC (Nov 30, 2019)

eXntrc said:


> I just stumbled onto this video from about 10 days ago:
> 
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> 
> ...


Yeah, I think one of the cameras etc dropped off and when that happens AP just fully turns off until you cycle the car (park, drive again) There was another video by Tesla Driver where it happened to him at 30mph heading down a road but I've been unsuccessful in finding it.


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## Ed Woodrick (May 26, 2018)

The human is always responsible today


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## ThatRandomGuyMC (Nov 30, 2019)

Ed Woodrick said:


> The human is always responsible today


Definitely. Good thing AP is here today but at the end of the day, you're driving the car.


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