schalliol

You can set the default distance preference closer in VCDS and change between dynamic, auto and comfort in individual (not sure what exactly the difference is on this setting). Would that be sufficient? If someone's going to fill the gap right in front of you, you should brake if they're in the zone where the closest would slow you down anyway. Why not just leave it on close and when someone does seem like they're going to come in brake such that cruise turns off?

snagitseven

The rear sensors (Presense rear) will not directly affect ACC or brake guard (I'm not sure but perhaps indirectly if the car behind collides and pushes your car forward towards another car while ACC is on, is tracking the car in front and your car and the one behind are moving at the time of collision). Presense rear is designed to detect an impending rear collision as follows:

If the system calculates a high probalility of a rear end collision, it will respond by tightening the seatbelts, closing the windows and sunroof, adjusting the front and rear seats, power head restraints, upper section back rests, and side bolsters.

As to rear end collision liability, you are correct, it's the driver's responsibility to be able to stop in time to avoid colliding with another vehicle. Where liability can get complicated is if a car #2 behind car #1 is hit by car #3 behind #2 and pushes #2 into car #1. Car #3 is usually responsible for damage done to both #1 and #2 but not always. There can be mitigating factors such as black ice, car #2 following too close to car #1 when hit by car #3, etc. Insurance companies have to sort out those situations. Believe me, I know.

superswiss

I use ACC on an almost daily basis in slow traffic and highway driving. My ACC doesn't have stop&go, so I can't use it in stop&go traffic, but I wish I could. I know exactly what you are describing. Unfortunately, most drivers in this country have zero concept of safe merging and safe following distance. Having said that, though, this situation is easy to deal with. First let me reiterate that ACC and all the other assist features are just assists features. They are meant to augment the driver and help reduce fatigue, but they are not at a point yet where you can leave them to their own devices and expect them to handle every situation, such as this one.

So, let's get to the situation at hand. The way I deal with this is simple. When somebody is cutting in front of me, I simply push forward on the stalk to cancel ACC. Not all the way, just the first position. Then I fall back and pull on the stalk to resume. Ultimately as the driver I'm still responsible and sometimes that means manual intervention. Never did I wish I could revert ACC to regular cruise control, though. ACC for me has made such a difference in mundane driving situations and I'm no longer fatigue on long drives or get frustrated in slow traffic.

schalliol

I'm with you superswiss. I definitely don't want to be tailgating people, and as good as the S6 brakes are, I still have to react. It takes about 1 second to react and depress the brake, which is just over 100 feet at 70 MPH.

BSullivan

At least in a 2012 A6, I can state categorically that if one of your front parking sensors fail, you will lose ACC and Brake Guard, the system does not revert to regular cruise control.
I had a sensor fail a few weeks ago with ACC engaged. When that happened, cruise control disengaged, and I received a DIS message that said essentially ACC and Braking Guard not available. No indication of the problem, just a statement of systems that weren't working.
I brought the car to the dealer, they replaced the left front parking sensor and all is good again.

Stoneybroke

If your ACC goes into panic stop mode and the moron tailgating with a 5000 lb. pickup rearends your A6, your estate will not be at liable.

schalliol

Say what you like, but ACC and emergency braking saves lives, and if it comes to it, pre-sense rear will help you. It's a good idea to use VCDS to enable emergency adaptive braking lights. If you're being tailgated, deal with it to be sure they don't tailgate anymore so that you're safe in the event someone fills the gap. If you have someone appearing to pull ahead of you so closely that even on the shortest ACC setting it wants to quickly brake, you are not fast enough to react such that if something happens where they dramatically slow, you WILL hit the person.

Option 1 you have a capable car that can get ahead if room. Option 2, you can gently activate the rear lights without slamming on the brakes such that the person behind you realizes they need to back away. Option 3, slow down gradually sufficiently that the other person will go around.

perlfather

Perhaps you, an experienced driver, would back off the throttle AND gently step on the brake and thus quickly disable the ACC.

schalliol

I have to tell myself not to press the brake to disable the ACC in such circumstances if I want ACC it to do its job, but my foot is always right there and ready if necessary. With cruise (adaptive or not) on, if someone fills the gap closely, I'm always braking because I know it isn't safe to tailgate

DB22

When you are driving with ACC and a car is about to cut in front of you then your interpretation of impending events is way sooner than any recognition by the ACC. ACC won't see the car until it's too late so your human intervention is warranted, as previously mentioned, it's to assist you, not instead of you.