ericblz
Posts: 56
Joined: Fri Jun 13, 2014 9:27 am

My i3 commited suicide via Active Cruise Control ACC

Sat Feb 27, 2021 12:26 pm

I normally drive with the active cruise control turned on and set to the speed limit. I figure besides tickets I can avoid running into unseen objects.

A few days ago I was driving along a 2 lane wide street behind a white F-150 pickup truck with silver bumper and large tow hitch. The light ahead turned red and he slowed to a stop. I coasted to stop behind him as normal because who would use brakes if you plan ahead?

As I came to a stop I looked down at the seat next to me to make sure I had everything I needed. Suddenly boom. Oddly the colllision warning system did not beep. The truck's tow hitch folded everything in the front of the car down to bending the aluminum frame. Sigh. RIP.

I later looked at my dash cam video. My car came to a near stop then silently accelerated right into the back of the truck. It was a bright sunny day at 1pm, no shadows, nothing odd. The system obviously saw the truck previously or I wouldn't have been able to slow in the first place.

I realize that the insurance company will consider it my fault no matter what but wondering if anyone else has had this or similar happen?

eNate
Posts: 664
Joined: Mon Sep 09, 2019 5:33 pm

Re: My i3 commited suicide via Active Cruise Control ACC

Sat Feb 27, 2021 2:34 pm

Ooh, tough one!

Yes, mine has behaved similarly. Using a camera and computer processing to determine whether an object is in front of you (rather than radar) depends on pattern recognition, and a symmetrical rear end of a car 100 feet ahead looks different than the same car 8 feet ahead.

It's a shame BMW didn't integrate the front parking sensors into this system because they would be a huge benefit, but alas, that's what we're stuck with.

As you implied, we're each the captain of our ship.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

ericblz
Posts: 56
Joined: Fri Jun 13, 2014 9:27 am

Re: My i3 commited suicide via Active Cruise Control ACC

Sat Feb 27, 2021 2:57 pm

I understand that the camera is the only source of input to the active cruise control, but shouldn't the collision warning system have beeped? I thought that was related to the front distance sensors.

eNate
Posts: 664
Joined: Mon Sep 09, 2019 5:33 pm

Re: My i3 commited suicide via Active Cruise Control ACC

Sat Feb 27, 2021 5:38 pm

Should, or does? As far as I know, the ultrasonic sensors are parking only, and all collision avoidance uses only the camera.

I don't know what conditions must be met for the PDC to activate, but I know in my 17 it doesn't if I'm driving. For example, under one pedal driving, if the street is relatively flat I often get that bit of creep instead of the car stopping completely. Early on I tested whether the PDC would sense a car stopped in front of me at a stoplight and cause the car to stop rolling. It doesn't activate, and I'm pretty sure wouldn't have stopped me from tapping it.

What I haven't tried is manually activating the parking sensor button on the center console.

But yeah, why this doesn't work as a poor man's radar I don't know -- it seems well suited for these instances.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

ericblz
Posts: 56
Joined: Fri Jun 13, 2014 9:27 am

Re: My i3 commited suicide via Active Cruise Control ACC

Sun Feb 28, 2021 6:28 am

Well it beeps when I pull into my garage which I suppose is parking at low speeds, and it would squawk if I'm coming around the corner and there was a parked car on the side which is likely camera. I'm astounded at how much the parts cost and how much damage a low-speed collision causes to lightweight parts. The airbags did not even deploy yet it looks terrible and they are claiming that the frame is bent and since it is aluminum it is a big problem. Sadness. Okay, thanks for your feedback.

If anyone else has experience or comments please let me know.

eNate
Posts: 664
Joined: Mon Sep 09, 2019 5:33 pm

Re: My i3 commited suicide via Active Cruise Control ACC

Sun Feb 28, 2021 10:02 am

Your story got me curious, so I cracked open the owner's manual and went for a test drive. Mainly because I don't recall the parking distance ever activating while pulling behind another car at a stoplight.

Per the OM, the system activates below 2.5 mph, and the front sensors only registers objects at distances less than 24" away.

What I observed was a slight delay in the system kicking in once I slowed to the threshold speed. At 2.5 miles per hour, the math says it takes 7 seconds to close that gap, but in reality it felt like no time at all. It was hard to get the system to activate without purposefully controlling my speed with the brake while approaching the car.

But it also felt like, at that speed, it would just be a light tap resulting in superficial damage. With your ACC active, I'm betting your car already accelerated beyond the threshold speed before you were within 24 inches.

I experimented with pressing the Parking button while driving. All it did was activate the self-parking system at speeds above 2.5 mph.

Perhaps most importantly, the PDC system is definitely not connected to auto braking. So even if you met the 2.5/24 conditions, you would have at best got a moment of tone to react to before the collision.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

eXodus
Posts: 136
Joined: Tue Dec 22, 2020 6:06 am

Re: My i3 commited suicide via Active Cruise Control ACC

Mon Mar 01, 2021 3:38 am

I think you can code that the front park sensors activate at a higher speed.
Going to do this later today.

Sorry about your loss.

While aluminum when it was bend - can not be bend back. If it's not bad - there are ways to repair it.

ericblz
Posts: 56
Joined: Fri Jun 13, 2014 9:27 am

Re: My i3 commited suicide via Active Cruise Control ACC

Mon Mar 01, 2021 7:11 am

Thank you for your kind words. This has been a real bummer.

It seems like body shops are incentivized to replace everything. For example both headlights look fine but he is telling me they need to be replaced at $800 each. The car's certainly declined in value but junking the car seems bad for everyone.

I would be interested in more information about your comment on repairing the aluminum frame since the body shop estimator seemed to imply it very challenging. I searched for aluminum frame repair and found a body shop near the other one, do you recommend going someplace like that which claims it as a specialty?

Fisher99
Posts: 402
Joined: Sun May 12, 2019 6:24 pm

Re: My i3 commited suicide via Active Cruise Control ACC

Mon Mar 01, 2021 11:46 am

I would definitely get a second estimate. I can't imagine that with the colission that you described that both headlights would need replacing.

However, I can tell you from experience, this will be an expensive repair. My i3 has been in the body shop for 6 weeks now, mostly waiting on parts, and the bill is approaching the $10k mark. And there was no frame damage.
2014 BMW i3 with Range Extender Engine, Capparis White/Frozen Black, 20" wheels,, Giga World, Tech + Driving Assist, Parking Assist, DC Fast Charging, TurboCord EVSE

EvanstonI3
Posts: 64
Joined: Tue Nov 03, 2020 9:11 pm

Re: My i3 commited suicide via Active Cruise Control ACC

Mon Mar 01, 2021 11:57 am

If you are going through Insurance for repairs, the Body Shop has to use new BMW parts. That's one reason it is so pricey and takes so long.
If you are paying out of pocket, they have the option to source used stuff for much less.
2 0 1 7 94Ah B E V

Return to “General / Main i3 Owners Forum”