gatorguy7

Yes, otherwise I wouldn't have expected it to do anything since I don't have it. But it is just a report of one person's experience with Audi's presense plus and the S6's huge brakes and great tires, because it still couldn't stop the law of physics.

dicktahoe

Page 88 of my manual states "Braking Guard works within limits and will not respond outside system limits, for example when approaching a stopped vehicle or stationary obstacle." So if car ahead was stopped before the system detected it, the braking guard would not have intervened. I once told my wife, "If you rear-end another car the only excuse I want to hear is that you laid down more than 100-feet of rubber trying to get it stopped!"

keithl

I know you probably do not think you are tail gating too close, but I find the sensors in the Audi to be very conservative. I have seen the pre sense kick in when cars turned too slow to my anticipation and thus the car kicked in. Once thing I knew that the A6 is confirming is that I tend to follow close to cars in front of me. I have always felt comfortable with the distance and my reaction time, but obviously the A6 engineers do not agree with me.

DeerHunter

Audi engineers are probably working from empirical data. You know, reaction time (much quicker-than-human reflexes, in this case), expected braking distances based on closing speed, etc, etc. You're basing things on the seat of your pants. I'll leave it to you to decide which is probably more accurate

snagitseven

That's exactly right. Same as when ACC is activated - the Presense Front will only activate for a stopped vehicle if the A6 is already detecting and following it in the same lane when that vehicle comes to a fast stop. Stationary objects not previously detected as moving in front will not trigger the Braking Guard. Nor will guard rails, bridge abutments, poles, walls, parked cars, etc. Then, there's the law of physics - if you're following too close at too high a speed, Brake Guard may not be able to stop your 4400 lb. Audi in time.

DeerHunter

You mean to say you canna change the laws of physics?

snagitseven

I've tried on several occasions. No joy and I have the scars to prove it.

jdong

I've had 2 incidents where Pre-sense Plus kicked in to some degree in the first 3000 miles of my A6, and here's my observations from it:

- One incident was I was trying to use ACC around a curve at 70mph, and I knew from past experience there was a high likelihood that exit lane traffic was backed up at a standstill around this blind curve. Sure enough, it was the case. The car, however, did not react until the rear of the stopped car was fully in view (while an attentive human driver would have realized seconds earlier). In this case I only got the auditory warning and I took over braking at that point, stopped in plenty of time.

- Second incident was a legitimate save. It was a long day after work and I was driving to an unfamiliar restaurant. At a highway interchange I got momentarily confused by whether I wanted East or West, and was paying more attention to the nav directions and road signs. Eventually I decided I wanted to go left, so while still looking up at the sign I pointed my car left and "BEEEEP" and felt the car jolt due to brake jabbing. Looked down and yup I had just pointed my Audi at a row of stopped cars, going 50+mph. I hit the brakes and felt the car "pull" the brake pedal from underneath me, and ended up stopping with about 5 feet to spare!

I think the latter case is one where Pre-sense Plus really saved my ***. It's one of those classic traffic mistakes that we all make from time to time, and I just happened to do it at a really bad time.

So I've noticed that the system does kick in, but does so at pretty much the last second. If I were sitting in the passenger seat watching this unfold, I would've started yelling and bracing for impact 3 seconds before Pre-Sense would've kicked in. It seems like in perfectly clear weather and ideal traction Pre-Sense Plus will bring the car to a stop in time, but most of the times it is designed to jolt you into paying attention, and mitigate the risk of a collision.

Also, note that the initial response of pre-sense plus is indeed just a sudden jab of the brakes. Not a full blown emergency stop. So a pre-sense false alarm is more of an inconvenience than a safety hazard. The manual states that if you increase accelerator input (e.g. trying to override the system intuitively), you'll disarm the pre-sense intervention.

RobRoy

In the context of my specific Use Case with false positives, all of my scary incidents happen when I am traveling at very slow speeds (under 25 MPH) and that there is a good distance between my Audi and the vehicle in front of me.

What shocks me is that the brakes kick in when there is NO CHANCE of collision. It is not like the vehicle in front of me has stopped in the path of the Audi. It is that wide swinging motion of the rear of the vehicle in front that seems to trigger a false positive thinking the vehicle is coming back into the Audi's path.

Really not an enjoyable experience.

I live in a rural area with lots of small towns, secondary roads and long bed pick-up trucks. I imagine that city folks or highway drivers would see this less often.

Frankie Lucky

Recently I got rear-ended by a lady after we stopped at a red light. I got out to take pictures and stuff. Then the lady said I backed up to her car!! I knew I didn't but can I mentioned this pre sense feature that would possibly explain how my car would not allow that collision? I need to win the case 100% as it was totally her fault! My Lexus would break if I say back up to a garbage container. Sure she could say I turned off the system and all that. But I plan to sue her and anything helps. Thanks