Strange Autopilot behavior. Can someone help me understand what happened?
I was driving home yesterday on an interstate. Speed limit was 70. I enabled autopilot with a speed limit of 70. Worked fine for a few miles, and then suddenly it set its max speed to 55 (but I know for a fact that there's no Speed Limit 55 sign there. There's no temporary speed limit sign for a curve, there hasn't been construction there in years, etc. Speed limit is 70, that's that.)
I manually pushed the accelerator to get us back up to speed, apologized to my wife, and adjusted autopilot speed back up to 70 with the right scroll wheel.
But when I took my foot off the accelerator, the car started slowing down below 70. I increased Autopilot to 75. Car still slowed down.
There weren't any cars in front of me, we were on an arrow straight, flat, road with no overpasses or anything else.
And importantly, it kept trying to slow down for like 3 whole miles when I took my foot off, so it clearly wasn't just a phantom braking incident.
There was no "autopilot speed reduced due to poor visibility" message on the screen.
There weren't slower-moving cars in the other lane (I was in the rightmost lane with no other cars around except behind me)
Eventually I just gave up, shut off autopilot, and manually drove the rest of the way home.
Any idea what happened there? That's happened to me before once or twice, but I've never had it take so long before
Posted Jan 9, 2023, 4:09 PM UTC
Autopilot is a blend of technologies.
Among them is the navigation data with GPS related information. It's not a perfect system.
Interstate 4, in Orlando, Florida, is my "go to" example for how bullshit Autopilot can be sometimes.
They recently moved the interstate over a few few such that the map no longer aligns with the GPS location of your vehicle, the result is that the car starts to think you're driving 70mph on surface roads with speed limits of 45mph, or less.
This results in some pretty harsh "rubber banding" where you're putting the speed up to 75mph, and the car thinks you're elsewhere, and pushing you down to a lower speed.
Along with the case stated above, if the road's been moved, and it thinks you're on the surface streets, it might also be reacting to "expected things" versus "actual things", such as there not being actually being a traffic light on the interstate, but expecting one based on where your GPS coordinates say you are, and so it starts to brake for non-existent traffic lights. In my case it was putting them in the visualizations, despite them not actually being there, stop signs too. Fairly positive that if you put a blanket over a stop sign, where the car is expecting to see one, it'll still visualize it, and react to it, even though it's "hidden", but I don't have the gumption to prove that.
Another issue that you can run into is when you pass weigh stations, there's one on I-75, for example, that has a "Maximum 45 MPH" sign as you pass it, when you're heading south bound. Big ass sign, but the car reads it, and throws you down to 45mph while you're going south on I-75. You know the sign is intended for the truckers entering the weigh station, but the placement of the sign is such that the car reads it, and runs with it.
There's also the Polk Parkway in Lakeland, where the speed limit is 65mph, but sometimes the car reads a sign that's intended for the road next to it, and it starts going 45mph.
In terms of the car slowing after you raise the speed limit again, if you hit the gas to speed the car up again, there is some weird behavior where it takes the computer a moment or two to get its shit together about how reality is different than what it thinks it is, and starts going back to normal again. Drives my wife nuts too, because I'll get the speeds set right, take my foot off the gas, and the car is like "But I was just going 45mph", and it brakes, assesses reality, and then goes back to the speed you've stated. This started in the last couple of updates I think.
Anyways, Autopilot isn't perfect.
Thanks for all the examples. I definitely still prefer autopilot to all the other driver assist systems I've tested (Honda sensing, subaru eyesight, VW TravelAssist, Kia/Hyundai's whatever-it's-called).
But yeah, it's frustrating when that randomly happens. It doesn't bother me as much when I'm alone in my car, but I feel bad when it jerks my wife's head forward and pushes my son into his (rear-facing) car seat.
Like somebody else commented here, I really wish they would give us a dumb cruise control, although even if they did, I'm sure they wouldn't let us Autosteer with dumb cruise. That'd just be asking for a lawsuit
I'd be fine with that kind of limitation. If someone really wants that kind of thing, maybe OpenPilot can be modded to do it.
Actually, I wonder if OpenPilot can be used to implement a basic cruise control.
I hear ya on your wife, and kids, not enjoying it. My wife gets pretty high strung when the car starts making mistakes and such, which is amusing because it doesn't do it that often. There's a spot near my house where it always brakes a couple times, and I know it's there, she knows it's there, it's just known that it is going to do it, but still, she's like "Just take control of the damn car!" as it's near the house, and it's slowing us down, technically.
My kids, on the other hand, are old enough that when Autopilot/FSD Beta does something stupid they're like "It's still learning!"
My wife would love dumb cruise.
Also for that matter then we could have any cruise when the sun is too low in the sky, too bright, too weathery out, or what-have-you.
We've had to drive hours of our road tris with no cruise at all because the sun is blinding the camera, even though we have radar.
Just did that stretch the other day.
Autopilot needs some sanity checking added. It's exceedingly unlikely that a road goes from 70 to 30 to 70 to 30, etc. Things like that can happen for construction, but it's not really detecting that for speed reasons/changes anyway.
They could also detect "hey, they've been on NO road for 9 of the last 10 minutes, so maybe this is a new road I know nothing about, and I should STFU about the speed".
It's really unfortunate that we can't have nice things because some dumb ass would set AP to 80 down a 25, get into an accident, and then blame Tesla, but I'd really love a "fuck off about speed changes for the next N minutes" option.
I4 is bad, and we go on a twice a year road trip to WI, and the Madison area is really bad at this too. Arguably worse because the cars have had like 2 years to learn the new construction.
I mean, I've been end to end on I-4, the only spot that gives me shit is Orlando.
Ultimate!
Well, that's where they did all the construction to widen the interstate. I really feel like they don't know how to integrate maps into their nav. For example, the military base near me closed a gate and built a new one. The system still insists on using the old gate even though it sees the road for the new one. Waze/Google understand to use the new gate but Tesla is clueless. I really feel like they need to change their mapping source to get better data.
Their mapping source is a bit blended, from what I can tell.
Have you checked OpenStreetMap to see if the data is accurate there?
I think one of the bigger issues is that we need more frequent map updates to be honest.
I agree, Orlando I get tons of speed changes that causes harsh breaking. I feel like this has to be from a recent update. possibly one before the Christmas one because I would take the turnpike pretty regularly up to Orlando and no issues like this before.
Orlando, at least on I-4, has been a miss for the four years that I've owned a Tesla.