[rs1987]

I had an unfortunate mishap today which I'm kicking myself about. I was stopped in heavy traffic at a red light. Something had fallen off my passenger seat, so I took off the seatbelt to allow me to reach down and while bent down into the passenger seat footwell, I managed to tramp on the accelerator by accident, rear-ending the car in front of me and shunting it into the car in front of it.

Now looking at my driver assistance settings, I have literally everything activated. The front collision warning is set to early and the emergency braking option is also set for front rear and sides.

I'm uncertain under what circumstances the emergency braking driver assistance should activate, but I can say that nothing activated. A distance of about a yard was enough to do considerable damage to the front end of my car and I'm wondering whether the driver assistance should have activated or not in this case. After all, what the hell is the use of an anti-collision system if it doesn't activate when needed.

Anyone with a better knowledge of what conditions would cause the emergency braking to activate able to comment?

[adeuel]

My guess is that it is only active while under way, not while at a standstill.

[pmsteinm]

Sorry to hear this. At least you weren't hurt and hopefully they can get everything fixed quickly.

In my owner's manual it does say this under Forward Collision Warning with light braking function:

"The system issues a two-phase warning of
a possible risk of collision with vehicles at
speeds above approx. 3 mph/5 km/h. The timing
of warnings may vary with the current driving
situation."

"The braking intervention can be interrupted by
stepping on the accelerator pedal with sufficient
force or by actively moving the steering
wheel."

And in their CYA box:
"Due to its limits, the system may not react, or
it may react too late or in a manner that is not
consistent with normal use."

So between those statements it sounds like in your case it wouldn't do anything.

[RichF90M5C]

Dude, how on earth can you blame the car for your own stupidity?

[ResIpsaLoquitur]

Originally Posted by rs1987

I had an unfortunate mishap today which I'm kicking myself about. I was stopped in heavy traffic at a red light. Something had fallen off my passenger seat, so I took off the seatbelt to allow me to reach down and while bent down into the passenger seat footwell, I managed to tramp on the accelerator by accident, rear-ending the car in front of me and shunting it into the car in front of it.

Now looking at my driver assistance settings, I have literally everything activated. The front collision warning is set to early and the emergency braking option is also set for front rear and sides.

I'm uncertain under what circumstances the emergency braking driver assistance should activate, but I can say that nothing activated. A distance of about a yard was enough to do considerable damage to the front end of my car and I'm wondering whether the driver assistance should have activated or not in this case. After all, what the hell is the use of an anti-collision system if it doesn't activate when needed.

Anyway with a better knowledge of what conditions would cause the emergency braking to activate able to comment?

Sorry to hear about this. What happened is so unfortunate. I also had an occurrence once where I did something similar with the car in gear but with auto hold enabled and caused the car to move forward. Fortunately, I caught it in time before a collision occurred. I make damn sure I hit the P button now before removing my seat belt or reaching for anything.

Even with all the nannies engaged, the car will not prevent you from slamming into something at low speed, It will only engage “at speed,” though I have yet to find exactly what that speed is. I think it’s because the car evaluates many parameters before deciding to engage the forward collision prevention. Merely being close to something you may hit is not enough. It’s the same reason that you could drive head on, but at an angle into a curb when parallel parking.

From BMW:

Forward Collision Mitigation assists in preventing accidents with other vehicles or unexpected objects. The Forward Collision Mitigation technology is constantly monitoring your environment (your speed, the speeds of the cars around you, the speed limit, etc.), and will automatically apply your brakes should you not be paying attention.

The Forward Collision Mitigation setting will also apply your brakes when other obstructions appear on the road. This may include other vehicles pulling out in front of you; people, deer, or other large animals crossing the road; or any other possible obstruction on the road.

(Emphasis my own). The second paragraph seems to be somewhat contra the first one though.

I believe that if you had received the red car icon first, then it would have applied the brakes automatically. But since you did not first satisfy the environmental factors necessary to get that icon, you didn’t get the subsequent emergency braking.

EDIT — pmsteinm posted his comment after I read your original post, but before I posted my response. He did a much better job of articulating what I was trying to say. He is right; in your case it wouldn’t do anything.

[rs1987]

Originally Posted by RichF90M5C

Dude, how on earth can you blame the car for your own stupidity?

However did you arrive at that conclusion and where did I blame the car? My very first sentence was "I had an unfortunate mishap today which I'm kicking myself about".

I'm just trying to understand why the driver assistance emergency braking did not activate.

From the comment by pmsteinm it's probably not meant to activate when moving from a dead stop. I'd assumed it would

[ResIpsaLoquitur]

Originally Posted by rs1987

However did you arrive at that conclusion and where did I blame the car? My very first sentence was "I had an unfortunate mishap today which I'm kicking myself about".

I'm just trying to understand why the driver assistance emergency braking did not activate.

From the comment by pmsteinm it's probably not meant to activate when moving from a dead stop. I'd assumed it would

You are correct — it will not usually engage from a dead stop.

[rs1987]

Originally Posted by ResIpsaLoquitur

Sorry to hear about this. What happened is so unfortunate. I also had an occurrence once where I did something similar with the car in gear but with auto hold enabled.

Yeah, that's exactly what I did. Auto-hold was enabled and I was stopped. I contorted to reach the footwell (I'm not very tall) and in my contortions, tramped on the accelerator. Doh!!

What makes it even worse was that as I was taking the seatbelt off, I thought to myself "put it in park. take off the auto-hold", but then saw the traffic lights changing so I didn't

[ResIpsaLoquitur]

Originally Posted by rs1987

Yeah, that's exactly what I did. Auto-hold was enabled and I was stopped. I contorted to reach the footwell (I'm not very tall) and in my contortions, tramped on the accelerator. Doh!!

What makes it even worse was that as I was taking the seatbelt off, I thought to myself "put it in park. take off the auto-hold", but then saw the traffic lights changing so I didn't

That is exactly what happened to me. Glad it was low speed and you’re okay. It’s frustrating for sure, but that’s all that matters.

I only had to nearly rear end a box truck to learn my lesson.

Also worth pointing out that this principle we are discussing also applies in reverse gear. You can absolutely back the car into something at low speed, including a solid concrete wall. The car will not prevent you from doing so, even if you have the indications on the camera screen that show you’re approaching an obstruction.

[rs1987]

Originally Posted by ResIpsaLoquitur

That is exactly what happened to me. Glad it was low speed and you’re okay. It’s frustrating for sure, but that’s all that matters.

I only had to nearly rear end a box truck to learn my lesson.

Also worth pointing out that this principle we are discussing also applies in reverse gear. You can absolutely back the car into something at low speed, including a solid concrete wall. The car will not prevent you from doing so, even if you have the indications on the camera screen that show you’re approaching an obstruction.

Instead of nearly rear-ending a truck, I rear-ended a Tesla which in turn rear-ended a brand new Mercedes. The Tesla driver told me he was driving back from the bodyshop as he'd had an accident and today it just got repaired. Poor guy. Bet he's cursing me.

I think I can safely say I've learned my lesson. No auto-hold without the seatbelt on.

[ResIpsaLoquitur]

Originally Posted by rs1987

Instead of nearly rear-ending a truck, I rear-ended a Tesla which in turn rear-ended a brand new Mercedes. The Tesla driver told me he was driving back from the bodyshop as he'd had an accident and today it just got repaired. Poor guy. Bet he's cursing me.

I think I can safely say I've learned my lesson. No auto-hold without the seatbelt on.

Oof! That’s rough. I feel bad for everyone involved. Thankfully everyone is okay at least! That sounds like you hit the Tesla pretty hard then, or, the Tesla was really close to the Mercedes.

[rs1987]

Originally Posted by ResIpsaLoquitur

Oof! That’s rough. I feel bad for everyone involved. Thankfully everyone is okay at least! That sounds like you hit the Tesla pretty hard then, or, the Tesla was really close to the Mercedes.

We were all about a yard or less from each other. It was bumper-to-bumper traffic. What's remarkable is how much damage can be done to the car with less than a yard of movement, although I guess that's the effect of almost 2 tons of weight and an excessive amount of horsepower. The pedal-tramp was quite hard in hindsight.

[ResIpsaLoquitur]

Originally Posted by rs1987

We were all about a yard or less from each other. It was bumper-to-bumper traffic. What's remarkable is how much damage can be done to the car with less than a yard of movement, although I guess that's the effect of almost 2 tons of weight and an excessive amount of horsepower. The pedal-tramp was quite hard in hindsight.

Agreed. This car can lurch quite easily.

[AHall]

I often wonder how this system works as well. When I pull into my garage I have limited length and the alarms go off as I get closer to the front wall. I wonder if it will stop on its on. Seems like it would if it has alarms but maybe not. I thought of setting up some road hazard comes to test the system.

Anyways really sorry about your accident.

[ResIpsaLoquitur]

Originally Posted by AHall

I often wonder how this system works as well. When I pull into my garage I have limited length and the alarms go off as I get closer to the front wall. I wonder if it will stop on its on. Seems like it would if it has alarms but maybe not. I thought of setting up some road hazard comes to test the system.

Anyways really sorry about your accident.

It is absolutely possible to hit the wall. There may be some perfect storm that would prevent you from hitting the wall, but you should know that it is definitely possible.

[RichF90M5C]

Originally Posted by rs1987

However did you arrive at that conclusion and where did I blame the car? My very first sentence was "I had an unfortunate mishap today which I'm kicking myself about".

I'm just trying to understand why the driver assistance emergency braking did not activate.

From the comment by pmsteinm it's probably not meant to activate when moving from a dead stop. I'd assumed it would

Apologies, my comment was a bit harsh. At least it was a fairly minor bump.

[Aronis]

Sorry to hear about this.

Quick Delete this thread and make up a better story.

What would Ralphie Parker say? Um.....

"Yes, a bee, a bee was in the car, startled me......they'll believe that....."

Mike

[rs1987]

Originally Posted by Aronis

Sorry to hear about this.

Quick Delete this thread and make up a better story.

What would Ralphie Parker say? Um.....

"Yes, a bee, a bee was in the car, startled me......they'll believe that....."

Mike

Some public humiliation is apt punishment for such a bone-headed mishap...

[///WeissBisBlau]

Very sorry this happened, OP, but thank you for sharing, as it is important for us all to know to be careful out there. At the end of the day, these things are all just driver AIDS, and do not replace the old noodle for operating the vehicle for us. This is not yet (thankfully) the movie Minority Report, where we have completely autonomously-operated vehicles.

[secretariat]

Originally Posted by Aronis

Sorry to hear about this.

Quick Delete this thread and make up a better story.

What would Ralphie Parker say? Um.....

"Yes, a bee, a bee was in the car, startled me......they'll believe that....."

Mike

Aronis your hysterical, I don't think they would believe you if you said you had a bee in the car in Binghamton in March. LOL

[Aronis]

Originally Posted by secretariat

Aronis your hysterical, I don't think they would believe you if you said you had a bee in the car in Binghamton in March. LOL

A mouse?

Mike