AP1 - MS Suddenly Veering Off Road On Road Crests - Any Similar Experiences?

[OK-S]

Hi Brainstrust,

My 2015 MS with AP1 plus MCU3 and all other SW upgrades was just on a 4,000 km cross-country trip. Flawless and enjoyable performance as usual EXCEPT that on completely straight sections of two-lane roadways (90-100 kph/55-60 mph) with rolling crests the autopilot began to exhibit abrupt veering behaviour. Even a couple of times on a rolling 4-lane section of motorway. These were short crests, but just high enough that one could not see the other side of them. In the past, the car would tend to keep its direction rather than veer off course.

Mostly the veering was towards the gutter (off the roadway) but a few times in the other direction towards the oncoming lane. I kept checking that it was not an anomaly (even did a dual button reset) but it was repeatable dozens of times and required quick intervention to correct it - essentially overriding the AP. The AP did not disengage by itself or offer any audible or visible warning - except when I took back control.

I have driven this car for over 40,000 km and have never experienced this behaviour before. The windscreen was not dirty and does not look visibly pitted in the lens area. The behaviour of the autopilot in other circumstances appears normal.

So, can this be a failure due to a more recent SW update or is the camera itself likely to be the cause? Or something else? There is clearly a safety issue here in my opinion. I will, of course, book for a service but I would like to be prepared should others have encountered and resolved this issue. (on SW 2022.8.2)

 

[OK-S]

Yeah, perpetual beta.
Based on 150,000 km AP1 for me hasn't changed in a couple of years. The last real change involved lane changes, where less of the car needed to be in the changed lane for one to release the turn stalk and not have the car snap back into the original lane.

Yet AP1 seems to be semi-organic, having good days and bad days. The same conditions on the same roads, the same time of the day, the same amount of cleanliness of the windshield, and painted lines, and somehow AP1 has behaved differently, slightly. It makes no sense but that is my observations. Just like a laptop when sometimes a program runs speedily and other times it is not as efficient, like something running in the background: mothership communication?
So one cannot download an update and do one drive and determine a difference; the same drive needs to occur several times, and if their car is like mine its tracking ability and precision will vary slightly. On really bad days my wife complains about getting sea sick and non-driver assistance "normal" driving is necessary. But I still have MCU1; maybe it is more consistent with MCU2 now.

The one factor not discussed here is the location of the sun. The same crest of road into the sun at certain angles will definitely adversely affect AP1 performance. So that might be the reason AP1 might be presumed to not work as well as before.

My impression is that things got better with MCU2 - perhaps simply the speed of processing inputs helps.

As for the sun position, it was in various positions over the course of our trip but seldom in front at a shallow angle - I would have discounted those. The weather was mostly clear and warm - ideal driving conditions.

 

[PCMc]

my car's AP has always been unreliable on hilly roads where the AP loses visibility of lines then tries to drive me off the road. I just don't use it in those scenarios anymore. I just never understood why they didn't use similar logic to crossing unmarked intersections where it defaults to going straight rather than freaking out.

Agreed - you would assume this would be the temporary default and easily programmed in. The misreading looks to instead be initiating a more drastic response.

I think the distinction is when it actually loses the lines versus it perceives a curvature in the lines due to the crest that does not exist.

In the case of the location near my home which I'll drive frequently, I will see the lane lines on the screen incorrectly indicate a bend as you crest due to how it's perceiving the curvature. In this case AP1 is just following the lines that is has [incorrectly] perceived which unfortunately wants to send me off the road.

There is different to another section on my test drive where a side road comes in during the middle of a gradual bend in the road. The side road has a center median, creating a large enough stretch without side lane marking. This gap causes my car clearly losing lane markings. This is one of the cases of loss of lines in the middle of a gentle bend after a subtle incline. In this case when AP1 loses the lines, it does default to going straight, which unfortunately is the wrong reaction to what it should do being to hold the line of the gradual curve which it had. This also tends to send my car into the curb at the far side of the intersection, which when the car recognizes, will suddenly throw up the red steering wheel/hands icon, disengaging autopilot, and telling me to immediately take over.

Just so happens both of these challenge cases exist within 1.5 miles of my home, so I drive them regularly (almost daily), and serve as part of my periodic regression testing for how AP1 performs. It also has helped me anticipate how my car may behave when I take trips and travel unfamiliar roads.

 

[dark cloud]

In the case of the location near my home which I'll drive frequently, I will see the lane lines on the screen incorrectly indicate a bend as you crest due to how it's perceiving the curvature. In this case AP1 is just following the lines that is has [incorrectly] perceived which unfortunately wants to send me off the road.

my car's AP has always been unreliable on hilly roads where the AP loses visibility of lines then tries to drive me off the road. I just don't use it in those scenarios anymore. I just never understood why they didn't use similar logic to crossing unmarked intersections where it defaults to going straight rather than freaking out.

It makes no sense to me either. If the car thinks it is going off the edge of the Earth, it might as well go straight off it. Why perceive a turn?
It should be programmed like this ship: If the direction was straight, go straight.

 

[David29]

Regarding intersections, there is a stretch of US 1 not far from my home where i sometimes use AP. It is a divided road, 2 lanes in each direction with turning lanes at some intersections. There is a spot where the road crosses a fairly wide intersection at a stop light. If there is a car ahead of mine as we cross the intersection, the AP follows the car ahead quite well, as it is supposed to (and the car indicates as blue on the screen to show it is doing that). If there is too much of a gap between us and the car ahead, or if my car happens to be first when the light turns green after a stop, the car does tend to wander a bit but (perhaps surprisingly) does try to proceed. It will eventually see the left edge marker or a lane marker as it crosses the intersection, and corrects itself, but it is not a very smooth crossing, shall we say. I try to avoid these situations at unfamiliar locations, as it is simply not worth the risk and hardly worth the trouble. I particularly tend to avoid places where I know the AP will struggle if I have passengers, as they don't like it.
After 6+ years with AP, I know it is best to let it work where it is good at it and not push it beyond its capability -- and I do know its limits fairly well by now. I still do get surprised once in a while.
And by the way, I vividly recall the very first time I tried using AP1 in circumstances similar to what the OP is describing, in November 2015, in the first few weeks after the very first release of the firmware, I was driving on an unfamiliar road in Maine, a two-lane non-divided state highway, in hilly country. It was a long trip, I was alone, and the traffic was light, so I was "experimenting." Cresting hills soon proved to be very challenging to the system, and I found myself drifting out of the lane and having to correct, so I turned it off. The last thing I needed was an accident far from home! And it those early days, Tesla said quite explicitly that the system was meant for divided roadways only, not undivided local roads. So I would have had no leg to stand on if I had an accident due to reliance on it....