Blind spot detection is not reliable

stevenh47 · 11-24-2023, 08:47 PM

Mine is 50e, and I noticed several times that the blind spot detection seems not reliable. Recently I got a chance to take this photo. (The camera angle is a little bit lower than my viewing angle) You can see a car in my blind spot mirror but the warning light is not on.

This is not always happening, actually it is good in 99% of time, but I believe the 1% failure worth enough to investigate $15 to buy a pair of those small mirrors. I always trust in simple things more, they are just more reliable.

TurtleBoy · 11-24-2023, 09:43 PM

Could be an issue or could be operating as designed. The system uses an algorithm taking into account the speed differential between the two vehicles. So for example if you were passing the vehicle on the right then it may not light up. Assuming you weren't, and your mirrors are fairy accurate, then it looks like it should have as long as you were going above the minimum speed.

You shouldn't be trusting the blind spot to tell you if it is clear. If it is lit then you know it is not clear, if it isn't lit then you need to check for yourself before making a late change.

Rob_G77 · 11-25-2023, 01:53 AM

Quote:

Originally Posted by TurtleBoy

The system uses an algorithm taking into account the speed differential between the two vehicles. So for example if you were passing the vehicle on the right then it may not light up.

I think it's something like this. The system is definitely selective about the conditions when the light will come on, not just if a car is beside you. It's more of a warning that a car has moved into your blind spot from behind.

Rob

crackerjack15 · 11-25-2023, 07:25 AM

Yeah, you were likely overtaking that car and the system assumes you already know i's there.

AGONXF30 · 11-25-2023, 07:51 AM

I believe it works fine in my car, but I do not rely on it. I use my mirrors as intended.

Qsilver7 · 11-25-2023, 10:19 AM

There’s a blind spot area & also the lane change area. Many BMW drivers that don’t use their turn indicator can miss their lane change warning. If the light isn’t illuminated…but there’s a car in our blind spot (like in the pic above)…if you were to initiate your turn indicator to move into that lane…and there’s a car in the blind spot or lane change area…then the steering wheel will vibrate and the light probably would have illuminated.

Can the OP verify that when the pic was taken….were you passing the car that was in the blind spot…or was the car in the blind spot approaching you? I would assume that you were passing or moving faster than the car in the blind spot.

stevenh47 · 11-25-2023, 11:52 AM

Alright, here are more details about the situation: I was not changing lane, not over speed limit, that car was approaching from behind.

So far, I couldn't find a pattern for when the warning light doesn't lit, but every time I observed that I believe it shall lit. Some times when I pass a car (not change lane) it doesn't lit, but when I pass second car, it lit. Same happens when cars passing me. So I really don't believe it's because of my speed or if I am using indicator.

And if the warning light is not on, I guess that means the car didn't detect the object in blind spot, I hence won't trust that the steering wheel will vibrate if I change lane.

TurtleBoy · 11-25-2023, 11:56 AM

Quote:

Originally Posted by stevenh47

And if the warning light is not on, I guess that means the car didn't detect the object in blind spot, I hence won't trust that the steering wheel will vibrate if I change lane.

You can approach it that way if you want but that is not how the system is designed to work (ie. just because it is not lit doesn't mean the system is not aware of the vehicle). Always checking your mirrors will be the safest way.

tooloud10 · 11-25-2023, 01:27 PM

TB explained this a while back too and mine appears to function as he says. I do still think it's kind of odd that BMW chose to make its system work differently than virtually every other BLIS feature on the market--on every other car I own the light is an indication that someone is next to you or in the blind spot and it doesn't make any assumptions beyond that.

The Libertine · 11-25-2023, 02:32 PM

Blind spot is to be used as an aid only - not an alternative to using and relying on your mirrors.

NoDTMF · 11-25-2023, 02:49 PM

Hi,

I have been also trying to understand BLISS and the Lane Departure Warning with active return functions. There are multiple settings like "Expanded" and "in dangerous situations" as well as a number of settings in BLIS section. I am wondering if there is a combo of settings that give us the "traditional" BLIS indication.

stevenh47 · 11-25-2023, 04:29 PM

Quote:

Originally Posted by The Libertine

Blind spot is to be used as an aid only - not an alternative to using and relying on your mirrors.

Yes, I am not sure how many other people would have the same thought as I assumed that the blind spot indicator could take the place of the the small blind spot mirrors. Luckily I fond this before got into any trouble and bought those mirrors.

nZtiZia · 11-26-2023, 08:29 AM

Quote:

Originally Posted by stevenh47

Yes, I am not sure how many other people would have the same thought as I assumed that the blind spot indicator could take the place of the the small blind spot mirrors. Luckily I fond this before got into any trouble and bought those mirrors.

what i've observed is if a vehicle is 'hanging out' in your blind spot, the warning triangle illuminates. if it's just 'passing quickly through' your blind spot, it won't illuminate. i set it to EARLY and just completed a road trip 300 miles each way. my cargo space was fully packed and blocked any view out the rear window, so by circumstance, i relied heavily on the side mirrors. the blind spot warnings functioned exactly as i explained above, though i agree with tooloud10 they should illuminate whenever a vehicle is in the blind spot always, no matter how transient

tooloud10 · 11-26-2023, 09:35 AM

Quote:

Originally Posted by The Libertine

Blind spot is to be used as an aid only - not an alternative to using and relying on your mirrors.

I don’t think anyone is saying otherwise but what’s the point of paying for and including the feature if many owners don’t find that it works reliably—whether that’s how it’s designed or not?

Marty in NY · 11-27-2023, 12:35 PM

FYI.. .. Just got back from an interstate drive and found my blind spot detection to be quite good/accurate. 2021 running 03/2022.52

I have my mirrors set as follows:
- Drivers side: put head against drivers window, adjust the side view mirror so you just see the side of your car
- Passenger side: put head over the middle of the center console, adjust the side view mirror so you just see the side of your car

I observed this many times today, at the point the drivers side blind spot detect light illuminated in my sideview mirror, I could see the passing car both in my rearview and sideview mirrors at the same time. The blind spot detection light stayed illuminated to the point where the passing car's rear bumper was about even with my front bumper and then it turned off. I have mine set for early detection. Couldn't really ask for anything better.

NoDTMF · 11-27-2023, 04:52 PM

hi,

Well, I went in to the menu settings and enabled BLIS and LANE departure warning settings to the most aggressive settings. On my drive, mostly on freeways, of 160 miles, the yellow lights seemed to work as I would want them to...they light up when I can still them approaching in the side mirror and stay until I see them through my side window.

As a side note, if you use the driver assist screen, you can see the cars on that screen approaching, passing, and in front of you. It can even tell you the difference between a car and a big "Boxie" truck- in that there is an image of a big boxie truck. I thought that was cool, maybe not useful...but cool.

Tejas1836 · 11-27-2023, 11:01 PM

Quote:

Originally Posted by NoDTMF

hi,

Well, I went in to the menu settings and enabled BLIS and LANE departure warning settings to the most aggressive settings. On my drive, mostly on freeways, of 160 miles, the yellow lights seemed to work as I would want them to...they light up when I can still them approaching in the side mirror and stay until I see them through my side window.

As a side note, if you use the driver assist screen, you can see the cars on that screen approaching, passing, and in front of you. It can even tell you the difference between a car and a big "Boxie" truck- in that there is an image of a big boxie truck. I thought that was cool, maybe not useful...but cool.

I found that very useful, especially on I35 from Big D to Austin

Mattgigem · 11-28-2023, 12:45 PM

This happens to me as well. I have only had mine for two months but twice now I have gone to change lanes and the indicator was not lit up to show that someone was beside me. I could not see them in the mirror. The only way I was aware of their presence was because I looked over my shoulder. I will check my BLIS and lane departure settings as suggested.

11-24-2023, 08:47 PM	#1
stevenh47 New Member 0 Rep 13 Posts Drives: X5 50e Join Date: Oct 2023 Location: California, US iTrader: (0)	Blind spot detection is not reliable Mine is 50e, and I noticed several times that the blind spot detection seems not reliable. Recently I got a chance to take this photo. (The camera angle is a little bit lower than my viewing angle) You can see a car in my blind spot mirror but the warning light is not on. This is not always happening, actually it is good in 99% of time, but I believe the 1% failure worth enough to investigate $15 to buy a pair of those small mirrors. I always trust in simple things more, they are just more reliable. Attached Images
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11-24-2023, 09:43 PM	#2
TurtleBoy General 13558 Rep 20,201 Posts Drives: 2019 X5 40i,2021 M340i Join Date: Jan 2019 Location: Colorado iTrader: (0)	Could be an issue or could be operating as designed. The system uses an algorithm taking into account the speed differential between the two vehicles. So for example if you were passing the vehicle on the right then it may not light up. Assuming you weren't, and your mirrors are fairy accurate, then it looks like it should have as long as you were going above the minimum speed. You shouldn't be trusting the blind spot to tell you if it is clear. If it is lit then you know it is not clear, if it isn't lit then you need to check for yourself before making a late change. __________________ 2021 BMW G20 M340i xDrive - Verde Ermes/Black - 03/2024.40 2019 BMW G05 X5 xDrive40i - Phytonic Blue/Cognac - 11/2023.50
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11-25-2023, 07:25 AM	#4
crackerjack15 Major 859 Rep 1,010 Posts Drives: 2024 X5 50e Join Date: Aug 2015 Location: West Virginia iTrader: (0)	Yeah, you were likely overtaking that car and the system assumes you already know i's there.
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11-25-2023, 07:51 AM	#5
AGONXF30 Captain 285 Rep 755 Posts Drives: 2012 335i S-Line/Melbourne Red Join Date: Apr 2015 Location: Upstate iTrader: (0)	I believe it works fine in my car, but I do not rely on it. I use my mirrors as intended.
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11-25-2023, 10:19 AM	#6
Qsilver7 Major General 4503 Rep 7,545 Posts Drives: F06 650ix GC / F15 X5 50i Join Date: Oct 2016 Location: Indiana, USA iTrader: (0)	There’s a blind spot area & also the lane change area. Many BMW drivers that don’t use their turn indicator can miss their lane change warning. If the light isn’t illuminated…but there’s a car in our blind spot (like in the pic above)…if you were to initiate your turn indicator to move into that lane…and there’s a car in the blind spot or lane change area…then the steering wheel will vibrate and the light probably would have illuminated. Can the OP verify that when the pic was taken….were you passing the car that was in the blind spot…or was the car in the blind spot approaching you? I would assume that you were passing or moving faster than the car in the blind spot. Attached Images __________________ 2015 F06 650ix Gran Coupe`(Moonstone/Cohiba Brown)\| 2014 F15 X5 50i MSport (Space Gray/Mocha) Become a BMW CCA member! Click HERE to join and feel free to use my BMW CCA member #191509 as a referral.
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11-25-2023, 11:52 AM	#7
stevenh47 New Member 0 Rep 13 Posts Drives: X5 50e Join Date: Oct 2023 Location: California, US iTrader: (0)	Alright, here are more details about the situation: I was not changing lane, not over speed limit, that car was approaching from behind. So far, I couldn't find a pattern for when the warning light doesn't lit, but every time I observed that I believe it shall lit. Some times when I pass a car (not change lane) it doesn't lit, but when I pass second car, it lit. Same happens when cars passing me. So I really don't believe it's because of my speed or if I am using indicator. And if the warning light is not on, I guess that means the car didn't detect the object in blind spot, I hence won't trust that the steering wheel will vibrate if I change lane.
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11-25-2023, 01:27 PM	#9
tooloud10 Captain 791 Rep 874 Posts Drives: '08 M3 convertible Join Date: Mar 2017 Location: USA iTrader: (0)	TB explained this a while back too and mine appears to function as he says. I do still think it's kind of odd that BMW chose to make its system work differently than virtually every other BLIS feature on the market--on every other car I own the light is an indication that someone is next to you or in the blind spot and it doesn't make any assumptions beyond that. __________________ M3 - X5 - 911 - Miata - Raptor - Edge
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11-25-2023, 02:32 PM	#10
The Libertine Major 1237 Rep 1,222 Posts Drives: 2021 Porsche Macan Join Date: Jul 2018 Location: South East, MA iTrader: (0)	Blind spot is to be used as an aid only - not an alternative to using and relying on your mirrors.
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11-25-2023, 02:49 PM	#11
NoDTMF New Member 0 Rep 18 Posts Drives: 2011 328i Join Date: Feb 2013 Location: CA iTrader: (0)	Hi, I have been also trying to understand BLISS and the Lane Departure Warning with active return functions. There are multiple settings like "Expanded" and "in dangerous situations" as well as a number of settings in BLIS section. I am wondering if there is a combo of settings that give us the "traditional" BLIS indication. __________________ 2024 X5 eDrive E50 (and a truck)
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11-27-2023, 12:35 PM	#15
Marty in NY Brigadier General 2784 Rep 4,415 Posts Drives: 21 X5 40i, 18 GTi, Snowblower Join Date: Nov 2014 Location: NY iTrader: (0)	FYI.. .. Just got back from an interstate drive and found my blind spot detection to be quite good/accurate. 2021 running 03/2022.52 I have my mirrors set as follows: - Drivers side: put head against drivers window, adjust the side view mirror so you just see the side of your car - Passenger side: put head over the middle of the center console, adjust the side view mirror so you just see the side of your car I observed this many times today, at the point the drivers side blind spot detect light illuminated in my sideview mirror, I could see the passing car both in my rearview and sideview mirrors at the same time. The blind spot detection light stayed illuminated to the point where the passing car's rear bumper was about even with my front bumper and then it turned off. I have mine set for early detection. Couldn't really ask for anything better.
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11-27-2023, 04:52 PM	#16
NoDTMF New Member 0 Rep 18 Posts Drives: 2011 328i Join Date: Feb 2013 Location: CA iTrader: (0)	hi, Well, I went in to the menu settings and enabled BLIS and LANE departure warning settings to the most aggressive settings. On my drive, mostly on freeways, of 160 miles, the yellow lights seemed to work as I would want them to...they light up when I can still them approaching in the side mirror and stay until I see them through my side window. As a side note, if you use the driver assist screen, you can see the cars on that screen approaching, passing, and in front of you. It can even tell you the difference between a car and a big "Boxie" truck- in that there is an image of a big boxie truck. I thought that was cool, maybe not useful...but cool. __________________ 2024 X5 eDrive E50 (and a truck)
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11-28-2023, 12:45 PM	#18
Mattgigem New Member 11 Rep 11 Posts Drives: 2024 BMW X5 50e Join Date: Aug 2023 Location: Denver iTrader: (0)	This happens to me as well. I have only had mine for two months but twice now I have gone to change lanes and the indicator was not lit up to show that someone was beside me. I could not see them in the mirror. The only way I was aware of their presence was because I looked over my shoulder. I will check my BLIS and lane departure settings as suggested.
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