[FirstMonday]

As the title said, the frontal collision warning system seems not working, when I approach front car with high speed, say 65 miles/hr on highway, it only worked once with audible and visual warning, then i repeated several times, only visual warning when i was super close to the front car. At local speed, never warned me. Then I did a test by putting two cardboards in front of the car, and drove 40miles/hr, there was no warning at all and hit the cardboard straight.( is there supposed to have a warning or brake intervention as the BMW advertised?) Plus there is not message from the system say "the system is deactivated", everything was ok from repair center's computer test. So anyone's x3 frontal collision warning system works this way? Does BMW designed like this way?
Cuz i test drove Posche and Toyota, they all very sensitive, gave warnings with reasonable speed within reasonable parameters. But my X3 seldom warn me even at super close distance and high speed.
BTW my car is 2018 X3 with driving assistant package, premium package, and m sport package

[TheMooseMan]

I'm no specialist but it seems that cardboard boxes are NOT detected well by the car sensors. That said, consider that your test might not be valid.

[teaston]

It will only work properly when the car in front suddenly slows, not when approaching a still vehicle/object.

[FirstMonday]

Originally Posted by teaston

It will only work properly when the car in front suddenly slows, not when approaching a still vehicle/object.

however, Porsch and Toyota will warn in the situation where high speed toward a still vehicle at traffic lights.
this is why m confused by my car.
the other brands warned under same situation but mine did not

[teaston]

Originally Posted by FirstMonday

however, Porsch and Toyota will warn in the situation where high speed toward a still vehicle at traffic lights.
this is why m confused by my car.
the other brands warned under same situation but mine did not

It will warn when approaching a stationary vehicle, but iirc not early enough to stop the car before collision if you’re doing over around 20mph. I think this is how all makes are, otherwise the warning would go off every time you approach a corner etc.

[MediaMan]

Originally Posted by teaston

It will warn when approaching a stationary vehicle, but iirc not early enough to stop the car before collision if you’re doing over around 20mph. I think this is how all makes are, otherwise the warning would go off every time you approach a corner etc.

Over 20 is not helpful.
My system is useless, alerted me going round a corner with parked cars on the bend last week. Tried all 3 settings and none are ideal.

[teaston]

Originally Posted by MediaMan

Over 20 is not helpful.
My system is useless, alerted me going round a corner with parked cars on the bend last week. Tried all 3 settings and none are ideal.

It will reduce the speed of the car enough to decrease the severity of the collision, possibly meaning it’s just car damage rather than people being injured or killed, so it’s far from useless.

Anyway, the vast majority of car accidents are rear enders where both cars were moving, so it does help a lot! It has saved my arse at least once.

[FirstMonday]

[QUOTE=MediaMan;24762060]Over 20 is not helpful.
My system is useless, alerted me going round a corner with parked cars on the bend last week. Tried all 3 settings and none are ideal.[/QUOT]

what BMW genius told me is the system only works at 35 mph....
and also told me all BMWs dont have audible warning...
that is why i dont trust them now

[FirstMonday]

Originally Posted by teaston

It will reduce the speed of the car enough to decrease the severity of the collision, possibly meaning it’s just car damage rather than people being injured or killed, so it’s far from useless.

Anyway, the vast majority of car accidents are rear enders where both cars were moving, so it does help a lot! It has saved my arse at least once.

then how can i test if the frontal collision system works or not? many thanks!

[Fuzz3D]

Originally Posted by FirstMonday

then how can i test if the frontal collision system works or not? many thanks!

Your strategy of using cardboard boxes may work if you first wrap the boxes in aluminum foil which should give them some radar presence. Cardboard alone will be pretty well transparent to radar. I've been considering using a similar strategy to test out the parking assist in an otherwise empty parking lot before ever using it around any actual large solid metallic objects.

Pro Tip #1: Remove kitchen appliance from box before testing

Pro Tip #2: Don't use your [soon to be ex] wife as a test target like that Tesla owner did

[Radar314]

I also tried this with boxes and convinced myself that the test was flawed. There are some real good videos of front crash testing on youtube.
I am also convinced that the sensors are the stereo cameras behind the rear view mirror. The youtube videos have a full sized car poster hung in the roadway.
The videos also show a pedestrian not getting hit. This kind of reinforces the non radar sensor theory. The person would not show up to radar but the software must know what a person looks like.
I have noticed the the accuracy of these cameras and the software they depend on can distinguish between real and fake speed limit signs. It has to be a real, conforming sign for the system to read it and display the icon.
IMO BMW uses the stereo cameras with sophisticated software recognition to discern vehicles, people and other obstacles.

[IM_ALL_IN]

The backup detection works with cardboard

[Radar314]

I am very sure the rear sensors are ultrasonic. I did find the cardboard box brought the X3 to an abrupt stop. I have had several vehicles that used the ultrasonic based pinging sensors to detect objects. Some had both front and rear sensors.
Some manufacturers call them parking sensors.
It surely is amazing how much technology is built into these vehicles.

[Fuzz3D]

Hmmm, disregard my box wrapped in foil advice unless you're making a tinfoil hat.

The technical training document on driver assistance systems clarifies things. Some of the equipment is optional so will depend on your trim level.

https://x3.xbimmers.com/forums/showthread.php?t=1563521

The front viewing KAFAS stereo camera appears to do the pedestrian detection, and KAFAS combined with the RADAR used for ACC are used for frontal collision warning & braking.

The 06_G01 Driver Assistance Systems PDF has gory detail on when the vehicle will give warnings or interventions, and what circumstances may not get detected.

[teaston]

Originally Posted by Fuzz3D

Hmmm, disregard my box wrapped in foil advice unless you're making a tinfoil hat.

The technical training document on driver assistance systems clarifies things. Some of the equipment is optional so will depend on your trim level.

https://x3.xbimmers.com/forums/showthread.php?t=1563521

The front viewing KAFAS stereo camera appears to do the pedestrian detection, and KAFAS combined with the RADAR used for ACC are used for frontal collision warning & braking.

The 06_G01 Driver Assistance Systems PDF has gory detail on when the vehicle will give warnings or interventions, and what circumstances may not get detected.

Correct.

And the park assist uses neither, it just uses the ultrasonic sensors dotted around the front and rear bumpers

[JayPichardo]

I can tell you from experience that the system works very well in my M40i. I have all my safety systems set to "early" detection. Have you looked over those settings?

[tonyb15re]

[JayPichardo]

[QUOTE=FirstMonday;24762319]

Originally Posted by MediaMan

Over 20 is not helpful.
My system is useless, alerted me going round a corner with parked cars on the bend last week. Tried all 3 settings and none are ideal.[/QUOT]

what BMW genius told me is the system only works at 35 mph....
and also told me all BMWs dont have audible warning...
that is why i dont trust them now

It works at all speeds, at 35-40 MPH the car is able to come to a complete stop using the system. There is a visual warming and then an audible warning if the driver does nothing.

[munna]

I find that other brands, such as my friends civic, is super sensitive and frankly annoying.

For the X3, it seems to do a better job of predicting scenarios that it needs to act on so that it minimizes false cases.

I've had the X3 trigger three times and the system worked extremely well and reacted much faster than I could have. All three cases prevented a collision

[teaston]

Originally Posted by munna

I find that other brands, such as my friends civic, is super sensitive and frankly annoying.

For the X3, it seems to do a better job of predicting scenarios that it needs to act on so that it minimizes false cases.

I've had the X3 trigger three times and the system worked extremely well and reacted much faster than I could have. All three cases prevented a collision

I think you need to pay more attention while driving!!

[munna]

Originally Posted by teaston

I think you need to pay more attention while driving!!

Nice try... before you come to a judgment, maybe you should first ask for context

First instance, a driver beside me turned into my lane and I was in their blind spot.

Second, pedestrian made a last second bolt to cross the street. It was a one way street and the individual looked the wrong way thinking it was safe and started to run cross

Third, driver in front of me slammed on their brakes to avoid the cops with radar. This is I could argue either way where I should have had more distance

[FirstMonday]

Originally Posted by JayPichardo

I can tell you from experience that the system works very well in my M40i. I have all my safety systems set to "early" detection. Have you looked over those settings?

yes, I did. I set to " early/always " for all the safety features. rest of them are very sensitive, but frontal collision warning.

I drove a porsch the other day, when i had a relative fast speed toward a still car, the car gave me warnings. but my BMW only worked once at 65 mph on high way with super close to front vehicle distance( i think the front vehicle had been pissed off)