[Lfk]

I use the active cruise control on my G20 330i quite a bit and it usually works well except this one scenario: the road is clear and I reach a red traffic light, with a car stopped (i.e. my car approaches a stationary car). It almost always screws up here and fails to detect the car in front until everyone in my car freaks out. A few times even the front collision system kicked in and braked (and beeped etc) before the cruise control system. I've now stopped relying on it in these situations and brake myself, thus deactivating the system.

Note that this happens only when I come up to a stationary car -- never with a moving car, which gets detected in time and it adjusts my speed accordingly.

Anyone else having this issue? BMW dealer told me it's a known issue with all of them and they can't fix it. I'm not convinced.

[wtwo3]

This isn't a BMW issue. This is a limitation of the technology. Active Cruise Control is not meant to be used on non-highway roads.

From my understanding, most radar based active cruise control and emergency braking ignore stationary objects because they have low angular resolution. They're great at telling you how fast objects around you are moving, and in turn help regulate the speed of your car, but not so much stationary objects. They're designed to be used on controlled access highways, where stationary objects are usually on the side of the road.

Further, emergency braking systems which do react to stationary objects only do so at very low speeds (usually below 20 mph). There's a very big reason for this. Imagine if you're driving along at 60+ mph, and the car falsely detects a stationary object and slams on the brakes. You're now at the mercy of how attentive and quick reacting the drivers behind you are.

It's also why we're inundated with warning signs/labels that it's still the driver's responsibility to pay attention, even if you are using these driver aids.

[Lfk]

Originally Posted by wtwo3

This isn't a BMW issue. This is a limitation of the technology. Active Cruise Control is not meant to be used on non-highway roads.

From my understanding, most radar based active cruise control and emergency braking ignore stationary objects because they have low angular resolution. They're great at telling you how fast objects around you are moving, and in turn help regulate the speed of your car, but not so much stationary objects. They're designed to be used on controlled access highways, where stationary objects are usually on the side of the road.

Further, emergency braking systems which do react to stationary objects only do so at very low speeds (usually below 20 mph). There's a very big reason for this. Imagine if you're driving along at 60+ mph, and the car falsely detects a stationary object and slams on the brakes. You're now at the mercy of how attentive and quick reacting the drivers behind you are.

It's also why we're inundated with warning signs/labels that it's still the driver's responsibility to pay attention, even if you are using these driver aids.

Off topic, but the front collision system definitely does 'something' at high speeds. I suspect it just primes the brakes. It's kicked in for me many times at 80+ kph, but I've always braked myself within milliseconds at which point it realizes you're paying attention and stops intervening (e.g. you may want to take evasive action rather than brake really hard).

[wtwo3]

Originally Posted by Lfk

Off topic, but the front collision system definitely does 'something' at high speeds. I suspect it just primes the brakes. It's kicked in for me many times at 80+ kph, but I've always braked myself within milliseconds at which point it realizes you're paying attention and stops intervening (e.g. you may want to take evasive action rather than brake really hard).

The issue again comes when the object in front is stationary. At 80 kph the car has to brake sooner than if it's travelling at say, 40 kph. So the chances of the system mis-interpreting something at a further distance are much greater, and at the risk of those driving behind you.

That being said, it will still attempt to alert you that you're fast approaching "something" in front, it just won't slam on the brakes for you, allowing you to make that decision on your own based on your own interpretation of what's happening in front of you.

Now if the car in front of you is moving and it slams on the brakes, your car will detect that the moving car in front is rapidly slowing down and will react accordingly, regardless of speed.

[hamera]

I'm pretty sure that mine is detecting stationary vehicles, slowing down and stopping behind them just fine. What's definitely annoying, in the UK the cars are often park on the side of the road and it is applying brakes even if you position the car between them and middle of the road markings. I've learn to act before it happens now and cancel/resume the system accordingly.

I'll have to do some more tests with the traffic lights scenario to confirm how it behaves.

[Lfk]

Originally Posted by hamera

I'm pretty sure that mine is detecting stationary vehicles, slowing down and stopping behind them just fine. What's definitely annoying, in the UK the cars are often park on the side of the road and it is applying brakes even if you position the car between them and middle of the road markings. I've learn to act before it happens now and cancel/resume the system accordingly.

I'll have to do some more tests with the traffic lights scenario to confirm how it behaves.

Please let us know. Especially because the newer are models are supposed to detect red lights as well (not sure if that's out yet), which is not very useful if you're going to crash into the cars waiting for the aforementioned red light!

[Flamingi]

Do you only have ACC or also Driving Assistant Pro? I have no experience with the current ACC, just with the DAP and it does detect standing vehicles correctly, brakes to a standstill and even starts driving on it's own when the car in front moves. It does sometimes detect parking cars, but that's overrules by stepping on the gas. Even though the DAP brakes later than I would, it's still far from anyone freaking out because of it.

While I do not have any experience with the current ACC, I do have it on my F11 pre-LCI (without the traffic jam assist) and there it also detects standing cars and I don't think the feature got worse... You even say the emergency stop assistant kicks in, so I think there is definitely something wrong, I'd go to the dealer and let them check the car.

[juhcobywankenobi]

The BMW system is pretty good at handling turns and detecting cars that are moving in front of you. I'll give it that, but terrible at noticing cars stopped ahead of it.

I've driven several rental cars, most recently a Ford Fusion that had ACC and it really impressed me detecting the car in front of it that was stationary. I could see the detection way ahead of BMWs and was impressed with it slowing down and stopping. I had no fear, meanwhile, my car I don't trust it at all with stationary cars, it rarely gets it right and I scare myself and any passengers if I let it try to detect the stationary car.

This is a limitation that the designers of the BMWs ACC have, but it's not the case for all cars.

[wtwo3]

Guys, this has absolutely nothing to do with BMW. It's a limitation on the technology.

https://www.wired.com/story/tesla-au...y-crash-radar/

Here's a good article explaining why the technology works the way it does.

Here's an excerpt:

"Volvo's semiautonomous system, Pilot Assist, has the same shortcoming. Say the car in front of the Volvo changes lanes or turns off the road, leaving nothing between the Volvo and a stopped car. "Pilot Assist will ignore the stationary vehicle and instead accelerate to the stored speed," Volvo's manual reads, meaning the cruise speed the driver punched in. "The driver must then intervene and apply the brakes.” In other words, your Volvo won't brake to avoid hitting a stopped car that suddenly appears up ahead. It might even accelerate towards it.

The same is true for any car currently equipped with adaptive cruise control, or automated emergency braking. It sounds like a glaring flaw, the kind of horrible mistake engineers race to eliminate. Nope. These systems are designed to ignore static obstacles because otherwise, they couldn't work at all."

[juhcobywankenobi]

Originally Posted by wtwo3

Guys, this has absolutely nothing to do with BMW. It's a limitation on the technology.

https://www.wired.com/story/tesla-au...y-crash-radar/

Here's a good article explaining why the technology works the way it does.

Here's an excerpt:

"Volvo's semiautonomous system, Pilot Assist, has the same shortcoming. Say the car in front of the Volvo changes lanes or turns off the road, leaving nothing between the Volvo and a stopped car. "Pilot Assist will ignore the stationary vehicle and instead accelerate to the stored speed," Volvo's manual reads, meaning the cruise speed the driver punched in. "The driver must then intervene and apply the brakes.” In other words, your Volvo won't brake to avoid hitting a stopped car that suddenly appears up ahead. It might even accelerate towards it.

The same is true for any car currently equipped with adaptive cruise control, or automated emergency braking. It sounds like a glaring flaw, the kind of horrible mistake engineers race to eliminate. Nope. These systems are designed to ignore static obstacles because otherwise, they couldn't work at all."

That article is two years old and also I've driven a Tesla it didn't do as good of a job as the 2020 Ford Fusion. What can I say, my real world experience with the Fusion is that it would detect the stopped car what felt like twice as far as my G20 and started braking much further. 🤷🏽*♂️

[wtwo3]

Originally Posted by juhcobywankenobi

That article is two years old and also I've driven a Tesla it didn't do as good of a job as the 2020 Ford Fusion.

I'm not sure the article being 2 years old has anything to do with it. Further, here's a screenshot from a 2020 Ford Fusion owner's manual showing cautions about adaptive cruise control:

[juhcobywankenobi]

Originally Posted by wtwo3

I'm not sure the article being 2 years old has anything to do with it. Further, here's a screenshot from a 2020 Ford Fusion owner's manual showing cautions about adaptive cruise control:

Again I'm not sure what differences are in the two cars, but it's very obvious that the Fusion detects the stationary cars a lot better. Very noticeable to anyone that would drive the two.

My hopes are they update the BMW system to do a better job, all the engineers have to do is drive a competitors car and witness the difference.

Also that is a smart warning to cover their asse(t)s 😊 But it also is written with "may not", the times I tested it the stationary car was detected and did a really good job slowing down and fully stopping. I wish my car did this.

[Lfk]

Originally Posted by Flamingi

Do you only have ACC or also Driving Assistant Pro? I have no experience with the current ACC, just with the DAP and it does detect standing vehicles correctly, brakes to a standstill and even starts driving on it's own when the car in front moves. It does sometimes detect parking cars, but that's overrules by stepping on the gas. Even though the DAP brakes later than I would, it's still far from anyone freaking out because of it.

While I do not have any experience with the current ACC, I do have it on my F11 pre-LCI (without the traffic jam assist) and there it also detects standing cars and I don't think the feature got worse... You even say the emergency stop assistant kicks in, so I think there is definitely something wrong, I'd go to the dealer and let them check the car.

I have Driver Assistant Professional which includes ACC. So if you're going 80kph (50mph), clear road, you come up to an intersection and a stationary car, does the car detect it in time and stop gracefully?

I have complained to the dealer at least twice. Once they said they calibrated the cameras, no difference. Second time they said it's a limitation of the system, which it appears may be them saying we don't know how to fix it.

[Lfk]

Originally Posted by juhcobywankenobi

The BMW system is pretty good at handling turns and detecting cars that are moving in front of you. I'll give it that, but terrible at noticing cars stopped ahead of it.

I've driven several rental cars, most recently a Ford Fusion that had ACC and it really impressed me detecting the car in front of it that was stationary. I could see the detection way ahead of BMWs and was impressed with it slowing down and stopping. I had no fear, meanwhile, my car I don't trust it at all with stationary cars, it rarely gets it right and I scare myself and any passengers if I let it try to detect the stationary car.

This is a limitation that the designers of the BMWs ACC have, but it's not the case for all cars.

Exactly this. After a while you don't want to wait and see what it does this time. I just brake long before I reach a standing vehicle now. Worth noting though, it works really well in stop and go traffic and at low speeds (as long as everyone's being nice, they don't cut you off etc).

Overall I'd say the experience is akin to teaching a dumb teenager how to drive.

[Flamingi]

Originally Posted by Lfk

I have Driver Assistant Professional which includes ACC. So if you're going 80kph (50mph), clear road, you come up to an intersection and a stationary car, does the car detect it in time and stop gracefully?

I have complained to the dealer at least twice. Once they said they calibrated the cameras, no difference. Second time they said it's a limitation of the system, which it appears may be them saying we don't know how to fix it.

There are not really any intersections in Germany where you arrive with 80km/h (except for country roads, but I have to brake there anyway), so I have not tested it with that speed. But with normal city speeds (up to 60km/h) it does detect stationary cars and stops. As mentioned earlier, it does react more on the late side, but not too late and the emergency brake assist does not intervene. Maybe you guys get a different system in the US similar to the removed anti dazzle high beams? Although regarding semi-autonomous/highly automated driving the laws in the US should be more liberal iirc.

I have the new OS7 update on my G05 which shows all the detected cars and it does show stationary cars at an intersection. I also assume the DAP is the same in the G20 as in my G05 (don't have a lot of experience with the DAP in the G20).

[wtwo3]

I'm not really sure how else to explain this, so I'll just leave it with this.

Radar based adaptive cruise control systems, REGARDLESS of manufacturer, all inherently exhibit the same limitations. BMW did not design, nor develop this technology. This is a 3rd party technology that manufacturers implement in their vehicles.

In fact this is pulled directly from a previous X5 owner's manual:

Limited detection capacity
Because of the limits to the detection capacity, you should be alert at all times so that you can intervene actively, if necessary; otherwise, there is the danger of an accident occurring.◀

Deceleration

The system does not decelerate when a stationary obstacle is located in the same lane, e.g., a vehicle at a red traffic light or at the end of traffic congestion.

The system also does not respond to:

▷ Pedestrians or similarly slow road users.
▷ Red traffic lights.
▷ Stationary objects.
▷ Cross traffic.
▷ Approaching traffic.

The way BMW, and other manufacturers, have tried to solve this limitation is through the integration of camera based systems in addition to radars. However, even those camera based systems have limitations inherent in them. The below is from the current 2020 G20 owner's manual.

So although they will do a better job of recognizing stationary objects through the help of camera based systems, there are still limitations there, and these systems are not meant to take full responsibility, or to be used on non-highway roads. The reason stop/go works well is because your speed is not significantly faster than those around you.

[Lfk]

Originally Posted by Flamingi

There are not really any intersections in Germany where you arrive with 80km/h (except for country roads, but I have to brake there anyway), so I have not tested it with that speed. But with normal city speeds (up to 60km/h) it does detect stationary cars and stops. As mentioned earlier, it does react more on the late side, but not too late and the emergency brake assist does not intervene. Maybe you guys get a different system in the US similar to the removed anti dazzle high beams? Although regarding semi-autonomous/highly automated driving the laws in the US should be more liberal iirc.

I have the new OS7 update on my G05 which shows all the detected cars and it does show stationary cars at an intersection. I also assume the DAP is the same in the G20 as in my G05 (don't have a lot of experience with the DAP in the G20).

I live in Australia (Melbourne) and plenty of intersections here where you reach going 80kph I'm afraid.

The thing that shows all detected cars is for 2020 models I think. Mine is MY 2019. Did you get that through an update after purchase?

[juhcobywankenobi]

Originally Posted by wtwo3

I'm not really sure how else to explain this, so I'll just leave it with this.

Radar based adaptive cruise control systems, REGARDLESS of manufacturer, all inherently exhibit the same limitations. BMW did not design, nor develop this technology. This is a 3rd party technology that manufacturers implement in their vehicles.

In fact this is pulled directly from a previous X5 owner's manual:

Limited detection capacity
Because of the limits to the detection capacity, you should be alert at all times so that you can intervene actively, if necessary; otherwise, there is the danger of an accident occurring.◀

Deceleration

The system does not decelerate when a stationary obstacle is located in the same lane, e.g., a vehicle at a red traffic light or at the end of traffic congestion.

The system also does not respond to:

▷ Pedestrians or similarly slow road users.
▷ Red traffic lights.
▷ Stationary objects.
▷ Cross traffic.
▷ Approaching traffic.

The way BMW, and other manufacturers, have tried to solve this limitation is through the integration of camera based systems in addition to radars. However, even those camera based systems have limitations inherent in them. The below is from the current 2020 G20 owner's manual.

So although they will do a better job of recognizing stationary objects through the help of camera based systems, there are still limitations there, and these systems are not meant to take full responsibility, or to be used on non-highway roads. The reason stop/go works well is because your speed is not significantly faster than those around you.

Correct this is why I said this:
"This is a limitation that the designers of the BMWs ACC have, but it's not the case for all cars." The designers of the BMW system does not mean they designed it, but it's unlikely the same designers did the one for the rental car I drove. Or if they did, they either updated it or used different cameras etc. Regardless it was better at detecting stationary cars, period.

I only hope one day BMWs system will
be as good or better than the system I drove. 😊🤔

[DES_MX]

Not sure how to post pics (as it's a text from online description of Active Cruise Control with Stop & Go functon in Netherlands), but in Dutch the description (amongst others) reads:

In tegenstelling tot zuiver met radar werkende systemen worden daarbij ook stilstaande objecten herkend, zoals auto's die voor een verkeerslicht staan te wachten.

Which translates to:

In contrast to systems operating purely with radar, stationary objects such as cars waiting in front of a traffic light are also recognized.

This is from current model year 460 EUR option, so not even full Driving Assistant Plus, just the active cruise options itself.
Therefore, ACC is advertised as having both camera and radar systems enabled and as being able to detect stationary objects, contrasting other competition solutions.

[Bmwphile]

Originally Posted by Lfk

I use the active cruise control on my G20 330i quite a bit and it usually works well except this one scenario: the road is clear and I reach a red traffic light, with a car stopped (i.e. my car approaches a stationary car). It almost always screws up here and fails to detect the car in front until everyone in my car freaks out. A few times even the front collision system kicked in and braked (and beeped etc) before the cruise control system. I've now stopped relying on it in these situations and brake myself, thus deactivating the system.

Note that this happens only when I come up to a stationary car -- never with a moving car, which gets detected in time and it adjusts my speed accordingly.

Anyone else having this issue? BMW dealer told me it's a known issue with all of them and they can't fix it. I'm not convinced.

I also have Driving assistant professional. I also agree that it does not pick up stationary cars, or it detects them later than before I'm prepared to brake.

[FrostNixon]

Originally Posted by DES_MX

Not sure how to post pics (as it's a text from online description of Active Cruise Control with Stop & Go functon in Netherlands), but in Dutch the description (amongst others) reads:

In tegenstelling tot zuiver met radar werkende systemen worden daarbij ook stilstaande objecten herkend, zoals auto's die voor een verkeerslicht staan te wachten.

Which translates to:

In contrast to systems operating purely with radar, stationary objects such as cars waiting in front of a traffic light are also recognized.

This is from current model year 460 EUR option, so not even full Driving Assistant Plus, just the active cruise options itself.
Therefore, ACC is advertised as having both camera and radar systems enabled and as being able to detect stationary objects, contrasting other competition solutions.

Was going to say the same, I bought this extra feature even without the driver assistance.

[srbs73]

I haven’t tried this in the 3 series yet, but I can 100% say my last car, 2016 Audi Q7, definitely did detect stationary cars.

Glad I read this thread if the behaviour isn’t the same, at least I’ll be ready for it!