automatic emergency braking activated in error - dangerous

[jessherbie]

I own a 2014 i3 Rex. While moving at 40 mph, my car detected that another car was in front of me and applied emergency braking. There was no car in front of me - it was some distance (at least 50 yards) away and there was not the remotest danger of me hitting it.
This presented a danger as my car jerked some to the right and it was hard to control for a brief moment. The system released on its own. I resumed driving and made it back home without further incident.
My parking brake is malfunctioning also. I plan to take it in for diagnostics at BMW.
To the best of my knowledge, the open recall on the software upgrade has been addressed already.
Anyone else have this happen? What could be the likely cause?

 

[eNate]

Wow, I'm surprised you got an activation at that high a speed! We're you by chance using ACC? Hopefully the newer software helps. I only rarely get activations at very slow speeds approaching stopped cars (maybe a little too hot) at stop light and stop signs, more often then not in rainy weather.

 

[g0rsq]

could have been sunlight hitting camera.

Not had it happen to me, but as it is a camera only system, and ACC can suffer with sunlight (glare) it could be related.

 

[mojo]

I've had "intervention with braking" at 50MPH - caused by a heavy goods vehicle coming the other way, crossing the central line lane marking slightly. In my case the intervention was not dangerous - but it did surprise me.

It did match BMW's description of how it's supposed to work (i.e. controlled braking, intended to mitigate the likely damage of a collision).

That was almost a year ago now. I've had no recurrence since. It seems to have been an edge-case for the system - perhaps something that BMW had not modeled fully when it was developed.

 

[808Pants]

How did I not know this was even a thing? 3 years of driving and I'd never heard of, let alone experienced this. What next: my '97 Dodge dually will reveal a self-parking feature?

 

[eNate]

Same, I'd better crack open the BMW textbook. I thought collision avoidance braking was limited to slower speeds ie. <20 MPH and also to ACC scenarios where the i3 is pacing a leading car and is showing the vehicle silhouette indication on the binnacle.

 

[mojo]

After that incident I checked what BMW's documentation says and (IIRC) it should only happen at lower speeds - but this was without any doubt the collision detection feature (rapid warning pips and the red warning light on the dash panel).

It was actually captured on my dashcam, but sadly with no soundtrack, so the only way to know when it happens is when my car jinks slightly to the left (we drive on the "wrong" side here). That was not the car, but my instinctive reaction to the unexpected braking - as we know, on the i3 you only get braking with collision detection, not steering intervention.

 

[alohart]

Same, I'd better crack open the BMW textbook. I thought collision avoidance braking was limited to slower speeds ie. <20 MPH and also to ACC scenarios where the i3 is pacing a leading car and is showing the vehicle silhouette indication on the binnacle.

From the I01 Driver Assistant Systems Technical Training Manual:

"The collision warning with city braking function extends the camera-based collision warning with a braking function from a speed of roughly 10 km/h / 6 mph up to a maximum speed of 60 km/h / 37 mph. If an acute warning is issued within this speed range, the vehicle is decelerated by 4 m/s² at the most.

The brake intervention is restricted to roughly 1.6 seconds. This avoids additional dangers for the
following traffic."

This is a feature only on i3's with a front-facing KAFAS camera in the rear view mirror housing and does not depend on adaptive cruise control being on.

I've experienced this only twice, when reducing the distance to a stopped vehicle ahead when our i3 was partially blocking a cross lane at an intersection. I'm surprised that my speed exceeded 10 km/h. This wasn't a surprise situation. I would have stopped on my own. The pierce audio warning, flashing red instrument panel icon, and sudden braking were surprising.