Autopilot slowing when passing trucks on highways

[zivac87]

When im driving on highways i usually set my car to max allowed speed at 140 km/h (87 mph). Everything works perfectly until i am passing truck which causes my Autopilot to slow down to 130 km/h (81 mph), then the moment it passes the truck it accelerate back to 140 km/h? Why is it doing that when truck is not even near my lane? when passing car it keeps my speed at 140 and acts like every other adaptive cruise control...

I have FSD but it shouldnt really matter much on normal highway cruise control

 

[EVRider-FL]

Maybe you’re seeing this, from the manual:

When moving significantly faster than vehicles in adjacent lanes, Model S automatically reduces the driving speed. This is especially helpful in heavy traffic situations or when vehicles are constantly merging into different lanes. When Model S detects other vehicles driving significantly slower, the instrument panel highlights the adjacent lanes with arrows and detected vehicles in gray, and Model S reduces the driving speed as appropriate. To temporarily override this feature, press the accelerator pedal.

 

[zivac87]

Yes you are right. Trucks in EU are limited to max 80 km/h and it is probably causing my AP to lower speed to 130 km/h. Its really annoying considering how many trucks are on highway

 

[YW555]

A few days ago I was going 80 mph in the center lane. As soon as I get between 2 slower vehicles on the left and right of me it slowed from 80 mph to 71 mph. I wasn't sure if it's phantom braking or Autopilot is being careful.

I've noticed that Autopilot have a hard time determining the exact location of a semitruck. It tends to jump all over the place when I get close to them. It's possible that Autopilot thought the truck was entering your lane because it has a hard time locating it.

 

[zivac87]

yes, hopefully it gets fixed because ap max speed is completely useless here in EU when you cant cruise without encountering truck every 20-30 sec on highway, it drives me crazy

 

[EVRider-FL]

yes, hopefully it gets fixed because ap max speed is completely useless here in EU when you cant cruise without encountering truck every 20-30 sec on highway, it drives me crazy

If your slowdowns are due to the feature I quoted from the manual, it’s working as designed so there’s nothing to fix. If on the other hand the problem is caused by your car thinking trucks are entering your lane, then I hope they fix that too.

 

[zivac87]

Those are slowdowns as stated in manual but slowdown should not be activated if trucks are driving at their maximum factory limited speed on highway. It just makes 0 sense and that is extremely stupid design. Not a single car i previously owned with adaptive cruise control was acting like that and all were capable of much higher speeds on ACC.

 

[Dewg]

Those are slowdowns as stated in manual but slowdown should not be activated if trucks are driving at their maximum factory limited speed on highway. It just makes 0 sense and that is extremely stupid design. Not a single car i previously owned with adaptive cruise control was acting like that and all were capable of much higher speeds on ACC.

The difference is in the name. Adaptive Cruise Control adapts to the speed of the car in front of it. Traffic Aware Cruise Control adapts to the speed of the car in front of it, and to the traffic around it. In most places it's common to encourage drivers to slow down when passing slower lanes, usually recommending no more than a 15MPH differential. The reasoning is simple: if you are driving by slower traffic lanes at a significantly faster speed, you risk the potential of someone darting from the slow lane into the faster lane, which cuts down your reaction time. In the case of the semi truck, there could be a car in front of the truck that darts over, or a car two lanes over in front of the truck that you cannot see yet, and that car darts in front of the truck and then in front of you.

I know you hate it and think it's stupid, but it's just common driving safety.

 

[zivac87]

Its not common driving safety in EU, its actually extremely dangerous what you suggest here. Passing trucks on autobahn with 15 mph differential when they are limited to 50 mph max speed is most likely getting you rear ended. Trucks are forbidden to enter passing lane on highways. Driving slower then 50 mph is considered as violation and is punishable for this very reason for small vehicles.

It just proves how much I wasted by buying FSD when they cant even adapt their basic highway autopilot function to 2nd biggest Tesla market. Is it possible to turn off FSD and to make this car act as a basic cruise control?

 

[Dewg]

Its not common driving safety in EU, its actually extremely dangerous what you suggest here. Passing trucks on autobahn with 15 mph differential when they are limited to 50 mph max speed is most likely getting you rear ended. Trucks are forbidden to enter passing lane on highways. Driving slower then 50 mph is considered as violation and is punishable for this very reason for small vehicles.

It just proves how much I wasted by buying FSD when they cant even adapt their basic highway autopilot function to 2nd biggest Tesla market. Is it possible to turn off FSD and to make this car act as a basic cruise control?

Sounds like you don't have the right car for your market. Hopefully you can sell it private party and purchase a car that fits your needs without too much of an impact on your finances.

 

[zivac87]

No, it sounds more that I wasted 8000 EUR on function that is not capable of doing simple highway cruise without constantly slowing and accelerating while draining my battery and brake checking traffic behind me on a passing lane while overtaking a truck, did i mention any other aspect of car that I dont like on this board? There is no need to defend Tesla unless you are Elon. This is simply bad and dangerous design that is easy fixable with few lines of code.

 

[PVia]

Curious if it's "common safety" in the EU to drive at 87mph?

 

[zivac87]

Its below average speed on most parts of Autobahn, and its not punishable speed on 90% highways in Europe. Its much more safe than brake checking while on passing lane, if they wanted to be concerned about common safety then lock speed at 130 kmh and call it a day, and put more specific info in car/FSD manual like every other manufacturer, this is simply stupid and dangerous.

 

[Dewg]

Sounds like a terrible, dangerous experience. Again, you should sell the car and buy one that will meet your needs. The car will never meet your needs, and even if the few lines of code were put in, the car is still limited while on Autopilot which is significantly slower than other Autobahn drivers, causing a dangerous situation.

The Mercedes EQS might be a better option for you, as it was designed with the Autobahn in mind.

 

[zivac87]

There is no need for sarcasm, we both know 1000 hp car is more then capable to deal with autobahn drivers. I knew exactly how fast autopilot is capable of cruising, and I did my due diligence well prior to buying this car, but, there is not a single reference speed at which this car starts to slow down on highways in any car documentation.

 

[Dewg]

I wasn't being sarcastic. Here is the Model S owners manual for Autosteer:

Model S Owner's Manual | Tesla

Learn about Autosteer and its specifications.

www.tesla.com

There is a section called "Adjacent Lane Speed" that discusses this function. You can override it by pressing the accelerator.

 

[EVRider-FL]

Is it possible to turn off FSD and to make this car act as a basic cruise control?

No, that isn’t possible. The only Teslas with basic cruise control are those without any autopilot features, but all Teslas made since early 2019 have AP. Like it or not, your only options are to use the throttle to override the slowdown or disengage TACC when passing the slow trucks.

 

[MrBadger]

Sounds like a terrible, dangerous experience. Again, you should sell the car and buy one that will meet your needs. The car will never meet your needs, and even if the few lines of code were put in, the car is still limited while on Autopilot which is significantly slower than other Autobahn drivers, causing a dangerous situation.

I think you re totally clueless to the situation. Its not just autobahn speeds, its any motorway speed. What you are suggesting makes Tesla not fit for the European (or probably many other) market so they can wave bye bye to a huge number of sales. Its a new behaviour, iirc 2023.6.x. Seems to be if you are passing a lorry (thats truck I think in American language), It suddenly knocks enough speed off to risk people rear ending you. This is not autobahn speed, this is regular motorway (I think you call that a freeway) speeds. If you cannot use a car and its features designed for the type of road you are on, then its not fit for the purpose.

 

[zivac87]

I think you re totally clueless to the situation. Its not just autobahn speeds, its any motorway speed. What you are suggesting makes Tesla not fit for the European (or probably many other) market so they can wave bye bye to a huge number of sales. Its a new behaviour, iirc 2023.6.x. Seems to be if you are passing a lorry (thats truck I think in American language), It suddenly knocks enough speed off to risk people rear ending you. This is not autobahn speed, this is regular motorway (I think you call that a freeway) speeds. If you cannot use a car and its features designed for the type of road you are on, then its not fit for the purpose.

Exactly. States are not in same situation cause lorry is restricted to much higher highway speed then our trucks, while their passenger car speed limit is lower then here, therefore autopilot is not braking during regular highway takeovers.

I would be fine with braking if AP spots lorry hugging middle lane or any suspicious behaviour, but when its driving maximum allowed speed while being in center of its right lane my AP should never start braking while overtaking lorry and nobody can convince me its for my own safety.

 

[zivac87]

No, that isn’t possible. The only Teslas with basic cruise control are those without any autopilot features, but all Teslas made since early 2019 have AP. Like it or not, your only options are to use the throttle to override the slowdown or disengage TACC when passing the slow trucks.

That would be solution if car wouldnt be able to speed over 140 km/h while mildly pressing throttle. Problem while being in plaid mode is that only the smallest pressure on throttle is needed (Im talking about 1-2 cm on throttle; you need to be extremely precise) for me to break the limit and lock my autopilot for rest of the drive and its tiring to do it every 20-30 seconds.