Autopilot lane change algorithm? Puzzling.

[Garlan Garner]

I am in need of finding out what the Model 3 uses for the lane change algorithm because my car changes lanes at the strangest times.


1. No one in front of me for a mile. No one behind me for a mile. Its changing lanes ( not often, but enough to be annoying at times ). Why?


How can we find out what is causing the decisions that cause this action? It must be buried in code somewhere - never to be known by customers.

 

[arghx7]

You need to tell us your model and AP hardware & software you have. Right now AP3 cars seem to have fewer issues with Navigate on Autopilot.

 

[Joshan]

were you in the far left lane? It moves out of that one randomly as it is a "passing lane". What setting is your lane change set to?

 

[Garlan Garner]

You need to tell us your model and AP hardware & software you have. Right now AP3 cars seem to have fewer issues with Navigate on Autopilot.

I just received HW3 a few days ago. Its doing the same thing as HW2.5.

 

[Garlan Garner]

were you in the far left lane? It moves out of that one randomly as it is a "passing lane". What setting is your lane change set to?

I normally travel in the middle lane. This time I was going exactly the speed limit in the middle lane.

Even so....why would it move to a passing lane when there is no one to pass? I had over 100 miles to go to a supercharger. I was at mile 40.

Setting? Average.

Would you happen to know the true Algorithm?

 

[diplomat33]

I am in need of finding out what the Model 3 uses for the lane change algorithm because my car changes lanes at the strangest times.


1. No one in front of me for a mile. No one behind me for a mile. Its changing lanes ( not often, but enough to be annoying at times ). Why?


How can we find out what is causing the decisions that cause this action? It must be buried in code somewhere - never to be known by customers.

I assume you are on Nav on AP with the "no confirmation" setting? That is the only way that the car will do auto lane changes "on its own", although it still notifies of you of auto lane changes and gives you the steering wheel nag before completing the auto lane change. And you can always cancel the auto lane change if you don't want to do it.

So what is NOA telling you? It will always flash a message like "changing lane to pass traffic" or "changing lane to stay on route" that hints at why it wants to do the lane change.

In terms of auto lane change algorithm, NOA will change lanes for the following reasons:
1) To pass traffic that is deemed too slow for your setting. It will only do this obviously if there is a car in front of you.
2) To keep you in the right lane for your nav route. For example, when a highway splits or to take an exit.
3) To move back into the right lane after passing a car.
4) To avoid traffic cones. HW3 only.

 

[TLLMRRJ]

Another big problem with Autonomous driving technologies.

We are expected watch over them, but we have no idea how they were programmed to behave, and the info on the screen is first of all completely useless when you are busy watching the road or catching the car doing something stupid, and secondly, Tesla is not giving you all the info that the computer sees to better understand what it's doing and why.

Everyone trying to learn why these programs do stupid things and when to use them and when not to use them and what to expect and how to save yourself from them is a ridiculous approach that is not fit for general consumption, only fanboys.

 

[Garlan Garner]

I assume you are on Nav on AP with the "no confirmation" setting? That is the only way that the car will do auto lane changes "on its own", although it still notifies of you of auto lane changes and gives you the steering wheel nag before completing the auto lane change. And you can always cancel the auto lane change if you don't want to do it.

So what is NOA telling you? It will always flash a message like "changing lane to pass traffic" or "changing lane to stay on route" that hints at why it wants to do the lane change.

In terms of auto lane change algorithm, NOA will change lanes for the following reasons:
1) To pass traffic that is deemed too slow for your setting. It will only do this obviously if there is a car in front of you.
2) To keep you in the right lane for your nav route. For example, when a highway splits or to take an exit.
3) To move back into the right lane after passing a car.
4) To avoid traffic cones. HW3 only.

Thanks for this wonderfully clear response.

All I know is that I ordered FSD and EAP when I got the car in Sep 2018. There were only 2 options at that point so I went ahead and purchased EVERY option available. Since then there have been a TON of names associated with what I purchased and unfortunately I haven't kept up with them. All I know is that I still have "everything".

Yes...I am set for "no confirmation".

I'm not sure what NOA is telling me. I am going to go out now and test it to see what it says. I didn't know it said anything since I really don't look at the screen much when I'm driving.

Be right back.

 

[diplomat33]

I'm not sure what NOA is telling me. I am going to go out now and test it to see what it says. I didn't know it said anything since I really don't look at the screen much when I'm driving.

The driver display part will give you alerts about why it is changing lanes. Also, the navigation section will have a blue box at the top with "upcoming lane change" that will alert you in advance when it is planning to do an auto lane change based on your nav route.

 

[Garlan Garner]

The driver display part will give you alerts about why it is changing lanes. Also, the navigation section will have a blue box at the top with "upcoming lane change" that will alert you in advance when it is planning to do an auto lane change based on your nav route.

So...I tested it over and over and every time the reason is the same.

Changing lanes to maintain route. <------- or something like that.

 

[lolder]

I was recently in a slow center lane of three with a steady stream of cars passing to the left in the fast lane. There was an opening in the right lane and the car auto-changed to that one.

 

[diplomat33]

So...I tested it over and over and every time the reason is the same.

Changing lanes to maintain route. <------- or something like that.

Ok. So there is your answer. It is changing lanes in order to be in the lane that it thinks you need to be in to follow your nav direction and get you to your destination.

 

[Garlan Garner]

Ok. So there is your answer. It is changing lanes in order to be in the lane that it thinks you need to be in to follow your nav direction and get you to your destination.

Understood, but it changes back about 3 miles later - with no one in front or behind me.

I drive a lot at night.

Weird.

 

[diplomat33]

Understood, but it changes back about 3 miles later - with no one in front or behind me.

I drive a lot at night.

Weird.

The map data might be wrong. It's been known to be an issue with NOA.

 

[Magnetic]

I've have this happen regularly 2018 M3, LR, AWD, FSD. Next time it happens look to see if an off ramp/exit is coming up. I found it would change lanes into the passing lane when an off ramp/exit was approaching and then it would change back after the off ramp passed, even though there were no cars in front or behind me. The worse part is it would want to change back to previous lane before the merge of the on ramp traffic. Again even without traffic it would do this behavior.

I am on 20.4.1 and was on several highways yesterday, unfortunately I had turned auto lane change off because another car was following us to our destination. I wanted to be able to allow room for them to change lanes when I changed and autopilot will just change lanes as it sees fit. They could of easily been held up or missed an exit because trucks got between us, so I manually did the changes. Anyhow, next time you're out, see if an off ramp/exit is approaching and if it does it. FYI - you can turn off auto lane change while driving, however you can't turn it back on until you park. At least on mine you can't.

I will turn auto lane change back on and see if it still wants to move to passing lane when an exit is approaching and I'll send in an update. Let us know if this is same behavior you are seeing too.

 

[Garlan Garner]

I've have this happen regularly 2018 M3, LR, AWD, FSD. Next time it happens look to see if an off ramp/exit is coming up. I found it would change lanes into the passing lane when an off ramp/exit was approaching and then it would change back after the off ramp passed, even though there were no cars in front or behind me. The worse part is it would want to change back to previous lane before the merge of the on ramp traffic. Again even without traffic it would do this behavior.

I am on 20.4.1 and was on several highways yesterday, unfortunately I had turned auto lane change off because another car was following us to our destination. I wanted to be able to allow room for them to change lanes when I changed and autopilot will just change lanes as it sees fit. They could of easily been held up or missed an exit because trucks got between us, so I manually did the changes. Anyhow, next time you're out, see if an off ramp/exit is approaching and if it does it. FYI - you can turn off auto lane change while driving, however you can't turn it back on until you park. At least on mine you can't.

I will turn auto lane change back on and see if it still wants to move to passing lane when an exit is approaching and I'll send in an update. Let us know if this is same behavior you are seeing too.

I'm traveling along in the middle of 3 lanes with no one ahead or behind me for a mile.

It moves over to the left lane, and then 3 or 4 miles back to the middle lane.

It doesn't do it at the same place every day. It seems random.

 

[Garlan Garner]

The map data might be wrong. It's been known to be an issue with NOA.

I'm not suggesting anything is wrong....

I just thought it would be interesting to know the real reason why the car does what it does

There only appears to be 5 or so messages for lane changes.

 

[hugh_jassol]

It moves over to the left lane, and then 3 or 4 miles back to the middle lane.

Yep. When I drive through certain areas using NOA in the HOV lane, sometimes it will get out of the HOV lane, then immediately get back in. Those areas are less frequent now than a year ago, but do pop up

 

[sperkin]

Yep. When I drive through certain areas using NOA in the HOV lane, sometimes it will get out of the HOV lane, then immediately get back in. Those areas are less frequent now than a year ago, but do pop up

Are you from Irvine? This happens all the time in Irvine after the Spectrum going i-5 North and also all the time at the 60 west near Fry's but that area is under construction so it fixed the NOA issue because it's now a wall.

Very embarrassing to drive in these two spots as the car will go in and out if carpool and then turn on the blinker like it want to change lanes into the wall once it's in the carpool lane. Cars behind me must me confused.

 

[hugh_jassol]

Are you from Irvine? This happens all the time in Irvine after the Spectrum going i-5 North and also all the time at the 60 west near Fry's but that area is under construction so it fixed the NOA issue because it's now a wall.

Very embarrassing to drive in these two spots as the car will go in and out if carpool and then turn on the blinker like it want to change lanes into the wall once it's in the carpool lane. Cars behind me must me confused.

Not from Irvine, but that's exactly where it happens to me.