Talbot

Thank you for the tip. I drive in "D" mode a little more aggressively on the accelerator (because, you kinda have to) and I find it easier to keep the revs down below around 4000 (based on manual's 'drive below 2/3 of max engine speed' suggestion). I hear what you're saying and I appreciate your insight, and I'll pay special attention to that. Right now I'm at about 350 miles.

3cat

I imagine in the near future we are going to be reading about collisions that were actually related to pre sense.
There have been so many similar type situations on the forum.

nickjwilliams

Count me in too please!

Yesterday was driving along a wid-ish (for UK!) road where there is room in between the single lane in each direction for a car to overtake, and suddenly it felt like the anchors came on and I seemilarly thought of a major fault but then saw the Audi Pre Sense and a big red exclaimation mark! The only thing I could see that might have set it off was a motor bike coming in the opposite direction pulling out to overtake a car (on their side of the road) - he wasn't that close to me that I thought it was an issue, but obviously the computer said it was!!

I'm just under 5000 miles in on a 6 month S4.

Regards, Nick

Versprechen

I've had those false positives too but there's a difference between those and slamming on the brakes.

I can instantly identify in those cases what the computer sees as a threat and disregard them -- as someone mentioned elsewhere people are bad judges when it comes to estimating speed and distance, so the computer throws out a warning that's legitimate from its perspective, but being human I'm confident that I can handle the object myself and so disregard it.

The only time the car has slammed on the brakes for me (and it felt just like hitting someone) was when reversing from a parking space in a parking lot and a crossing car sped very fast past my rear -- the warning light and brake slam was hard and accurate but after the fact. Scary but no harm done.

pb12

i have an S4 on order so I have not had a chance to experiment with this tech on an Audi. I currently drive a 2011 E550 4matic which I bought new, with what was 6 years ago, the state of the art Mercedes Distrionic system. I have been a huge proponent of these driver systems from my first experience with them. I am concerned with how these systems are being described by current owners however, because I can absolutely see where the Car could cause an accident by slamming on the brakes, just as you attempt a cross, or from miss-identifying an oncoming car as described above.

My question is, can these systems sensitivity be reduced, or can certain parts of the system be turned off completely, while leaving other parts of the system active?

Thanks!
M

Versprechen

My point was in my case several times it warned only and did not slam the brakes. It saw a potential threat but was smart enough to just post a heads up.

The one time it did when in drive it saved my car and the one in front.

The one time it did in reverse was when the crossing car whizzed by so fast Pre-Sense could only catch it in retrospect, which is hardly a danger when in reverse if you think about it.

Seems fairly smart to me -- my anecdote to counter the future fatal anecdotes on this board.

superswiss

Yes, it can be controlled and even turned off in the MMI. I've had "PreSense" for the past 4 years in my RS5. It's the previous generation system before it was called "PreSense". "PreSense" is an umbrella term. What we are really talking about here is the brake guard feature, which automatically applies the brakes in an emergency. I honestly don't see the concerns people have. Based on my experience I strongly feel those with these kinds of issues are actually not keeping a save distance. I'm a fairly sporty/aggressive driver, so I'm no stranger to my own limits, but I must say PreSense did teach me to be more defensive in daily driving. The reason I'm saying this is because PreSense actually has multiple stages. It doesn't just slam on the breaks whenever it senses danger. It goes through a series of stages. It first alerts you visually and audibly. If the driver then doesn't react with an evasive maneuver etc. it moves on to the next stage and briefly jolts the brakes to wake you up. If you still don't react, only then does it a full on emergency brake maneuver. Now having said that, there obviously needs to be sufficient time to go through all these stages. If there is not sufficient time, because you didn't follow at a safe distance for example or drove too close to an oncoming car, then it may go straight to full emergency braking, because there just isn't enough time to warn you.

I regularly get the visual and audio warning, but so far I only had one instance where it misread the situation and stepped on the brakes. It can happen, these systems aren't perfect, but it has also saved my bacon on several occasions.

pb12

Thank you for this explanation, the system sounds very similar to the one in the car I have been driving for the past 6 years. As I mentioned, I am a huge advocate for these defense systems. As much as I try and be a very attentive driver, who cares deeply about "driving" in general, I'm far from perfect. The system in my car has saved my bacon in a serious way, on three separate occasions over the last 6 years. it has given me the audible alarm on far more occasions, but the vast majority I was already on the job.

Now, having said all that, the one system I am concerned about is the system employed while turning across traffic as described earlier in this thread. those situations can be ones which you've got to get on with it, and there may not be a great deal of margin for error. The last thing in the world I want is for the car to stop in the middle of the maneuver.

Thanks again
M

superswiss

Yes, those situations have been reported a few times, but it's just hard to tell what exactly happened without having been there. Human memory is often selective and we are quick to blame something else. It might be scary the first time and it does perhaps have a learning curve, but in my experience and based on what I've read, the system can be overwritten by being assertive on the throttle and/or steering wheel. The system doesn't just read the situation outside your car, it also reads what you are doing. So if it sees you make an evasive maneuver then it won't interfere or you can also counteract the braking by stepping on the throttle. It will immediately let go off the brakes. However, if it sees you hesitate and letting off on the throttle, then it will continue to try to avoid a possible collision.

It is certainly possible for a driver to react the wrong way, because they get surprised. That hasn't happened to me yet. I usually react instinctively. For example, the time where the system mistakenly jolted my brakes I instinctively stepped on the throttle and it immediately let go. It was certainly a bit of a surprise, but I think if you practice situational awareness and are an attentive driver, your brain should quickly realize whether you are in danger or not.

Talbot

I really don't know what my reaction was when it happened...but I do remember it was a hell of a jolt. I thought there was some serious malfunction in the engine or transmission, so likely I, too, added to braking to avoid stopping right in the oncoming car's path.

The one thing I am 100% sure of is that outside of the car's intervention, I could, have easily completed my maneuver without even cutting it close. Heck, my wife was in the car, so I know I accounted for an even larger margin of safety. Again, I'm especially aware of the situation on this particular turn. Moreso than a normal, casual drive.

Also, I'm not considering defeating the system because of a one-off incident. Next time, though, I'll be better able to contain my bladder!