q5q7

under low speed?

I have the driver assistance package but never had the chance to test this out.

the only functionality so far(I've experienced) is a warning light in the dash and seat belt tension itself if someone is approaching from behind too fast and too close.

keithl

Form the videos on YouTube and the manual it is worded to say it will reduce the intensity of a collision I do not think it will prevent it in certain situations. I had it kick in a once when a car in front of me slowed saddenly to make a turn and while I felt it start to brake I am not sure it would have braked enough. I am sure some of the wording is legal requirement as to not set a false sense of expectation that it will prevent the impact in all cases.

q5q7

I am curious will it do something like this?

Richard Solomon

Dunno ... but I want that inflatable crash dummy!!!

Homer1946

The manual is VERY specific on what the car will do and stopping completely is not how it is designed. Other cars are programmed to completely stop and in fact there was recently a news reports (forget which station) that dinged Audi for not adequately stopping (automatically) to completely avoid a collision.

I am too lazy to read the manual right now but the protocol is something like this.

Imminent collision (in each case assume you don't do anything):

System provided visual and auditory alert (and if you do nothing...)
System provides brief sharp braking to get your attention
System then starts slowing at 3m/s/s.
System then starts slowing at 5 m/s/s.
(something like) 1/2 second before the collision the system slows down at full breaking.

Homer1946

Oh, yea, I forgot. If at ANY point you touch the brakes the system takes that as permission to apply whatever braking force is necessary to prevent the collision (if possible).

in2dwww

Not exactly. If you do nothing at all when that warning comes up, the car will brake hard. It's happened to me twice. It's standard operating procedure now to give more distance to the car turning right into a driveway, since if you keep a 3+ second gap and don't change lanes or slow down and the turning car takes it's sweet *** time pulling into the street or driveway, the car will brake.

Just today, in fact, I actually kept my foot on the accelerator and the car continued to brake. It first slowed down but then went hard on the brakes. I did not reach full stop because the offending slow turning car got out of the way. I'd say it left about a 20' gap after it started to brake hard. But it was starting to brake about 50' away.

When it happens, you'll know.

snagitseven

There are 4 or 5 pages in the manual dedicated to Presense and Braking guard. There are actually 3 levels of Presense; Presense basic (all Audis), Presense Rear (included w/Side Assist) and Presense Front (included with ACC). Presense Plus includes all three systems.

The Presense Front is directly coupled to the Adaptive Cruise Control (ACC), includes Brake Guard and like ACC, at 20 mph+, monitors followed vehicles and does not recognize stationary or small objects like people, some bikes, etc. If a followed car in front suddenly slows or stops, the Brake Guard will first provide a visible warning in the DIS followed by an audible tone and if the driver doesn't respond appropriately, will attempt to slow by applying the brakes and, if necessary, attempt to brake the car to a full stop. The Brake Guard will not engage if it comes upon a stationary object including a previously stopped vehicle that wasn't already being tracked by the ACC or a wall, tree, light pole, etc.

My take - It's really a matter of design philosophy. I believe Audi designed the system to avoid collisions with the least amount of automatic intervention in order to not excessively intrude on the driver's control. In other words, I think Audi could design a system to alert and stop the car sooner for earlier warning of a collision but it would be at the expense of more frequent alerts and earlier auto braking, perhaps to the "nannying" frustration of drivers. Consequently, as designed, Audi states in the manual that their safety systems (or all others for that matter) cannot overcome the laws of physics. No auto braking system can stop a 4000 vehicle traveling at 45 mph in time as a car pulls out of a driveway right in front of you or a car in front comes to a screeching halt if you're too close.

An automatic accident avoidance system can't totally prevent a collision while at the same time, not intrude with the driving experience to some degree. I, for one, would not want an automatic accident avoidance system that engages too soon and too frequently, overriding and dampening my driving enjoyment. As the Audi systems are designed, I feel it's probably a reasonably balanced compromise between safety, comfort and driver control. At the end of the day, like ACC, Side Assist, Lane Assist, cameras, etc, Presense and Brake Guard are aids, not replacements for common sense; the driver must still ultimately be responsible for the safe operation of the vehicle.

I think it's important that every owner spend a few minutes to carefully read the manual sections addressing the various Presense and Brake Guard systems as equipped in their own vehicle. Forewarned is forearmed.

q5q7

The key point from reading the manual and the replies is that the Audi Brake Guard won't stop you "when approaching a stopped vehicle or stationary obstacle".

snagitseven

Correct, unless the Presense Front/Brake Guard system was already detecting a moving vehicle before it stopped. (The manual states so long as Brake Guard is not turned off in the MMI and the ESC button is not disabled by the driver, it will detect a moving, followed vehicle even if ACC is not activated).