recreation

Picked up my new A4 last night. Driving it home with ACC set at 75 in a 65 mph zone, I was in the left lane almost past a slow 18-wheeler, when a guy driving _extremely_ fast suddenly appeared in my rear view mirror.

At that very instant we must have entered a 55mph zone. My new car hit the brakes hard! The guy coming up behind me had nowhere to go and no time to slow down. Fortunately there was a broad shoulder on my left and all I heard was a loud buzzing sound as he flew by on the rumble strips.

This won't do, but I don't know this car well enough to know how to keep it from doing that again. Ever!

JDA_yeg

What were you doing driving 75 in a 65 zone?

Anyways, I heard somewhere on this forum where they had a similar situation occur... I'm definitely not going to get the advanced driver assistance package! Especially when there are A LOT of terrible drivers where I live!

I'm glad you're okay!

DirkM

You can turn this off in the MMI/Car/left button/Driver Assist/Traffic Sign Recognition or similar, there is an option. ACC is great with auto adjustment based on detect speed limit DISABLED.

superswiss

Yeah, by default Traffic Sign Recognition feeds the recognized speed limit to ACC and then ACC automatically takes it and slows the car down. Obviously if you are entering a 55 mph zone at 75 it's going to slow down rapidly to 55. As said, this can be turned off. Hopefully, the other guy learned his lesson.

bob m

Yes, this is an issue sometimes, but one time is one time too many. I know I sound like a broken record, but people really do (and many times don't) keep a safe distance from the car in front of them, hence so many rear end accidents. I'm hoping that this awakened the guy in back of you enough to make him think twice about doing that again, but its probably wishful thinking on my part.

recreation

Thanks all. Just checked the manual (imagine that!) and found this on pg. 111 under "Predictive Control." Cool idea, lousy implementation. I'll turn it off the next time I get in the car.

One would think those brilliant German engineers would have anticipated that scenario. That guy's excessive speed behind me was unusual. But suddenly braking 20 mph while there's a clear road ahead of you is a recipe for disaster almost any day on the freeway -- if not for you then for the inattentive driver 3 or 4 cars back.

-J

73JPS

With no disrespect intended, and only because I found the menu chain to be completely un-intuitive for this selection, the correct sequence of menus and sub menus is MMI/Vehicle/(left button for options)/Driver Assistance/Audi adaptive cruise control/Predictive control/Set speed limit/Off

At least that's what it is for a Canadian car with a manual transmission. Thanks for posting that it can be disabled though, because before I read this thread, I'd been suffering with it on until today.

Bob Petruska

I really understand your concern here.

Where I live most people travel I81 at about a common 75 MPH in a posted 65 MPH. There is a section of I81 where it abruptly drops from 65 to 55 MPH (fines are doubled sign posted), and no one slows down at all, they still go 75 MPH. If an Audi hit the brakes when it detected the 55 mph sign, the worst multi vehicle accident in PA's history would occur.

bob m

Hey Bob,

And I share your concern here too. But I'm not sure I totally understand this feature in the ACC. Many times I'm driving about 10 or so above the limit on the highway and then the signs post another 10 mile or so speed reduction and I don't remember my car slowing down to meet the lower speed. Yet, on some streets I remember this sometimes happens.

VM

Bah, that's nothing. Around here, most people drive around 115-120km/h, and I've occasionally had the traffic sign recognition recognize a sign from a side road that's angled just a little wrong that says 70km/h. So the car will dutifully brake to 70km/h. Oooooops.

Personally, I think Audi should have an option where it keeps the same margin, so if you're going 115km/h when the speed limit is 100km/h, and the speed limit drops to 90km/h, it should set your speed at 105km/h rather than 90km/h.

I finally gave up and turned this off a few days ago. Great idea but bad implementation in places where EVERYBODY speeds...