Adaptive Cruise Fails to Brake to a Stop - Nearly Hits Car!

BZ888 · Jan 2, 2014

Hi Guys,

Really need some user input on this issue with my Adaptive Cruise Control.
Driving on the motorway at about 100km/h. Distance setting is on Distance 1 with Dynamic.
Car in front of me is detected and the A3 is tracking the car for at least 4-5 minutes before the issue.

The car in front of me brakes quickly and heavily. No warning tone from the Adaptive Cruise. A3 brakes far too slowly. I quickly have to jump on the brakes before we hit the car in front!!

This has happened twice now in 2 separate occasions. It is very disconcerting as it makes you loose any faith at all in the system. I understand it may not react in time, but if this is the case a WARNING tone MUST alert the driver. But it doesn't. I can't believe the system hasn't caused lots of accidents?? The current implementation of it is very unreliable...crazy Audi can get away with it.

Anyone experience the same problem?

cemerson · Jan 2, 2014

No, don't have that problem. The fact that you are on distance setting 1 might have something to do with it... I get warning tones and pre-sense comes in and brakes as well when that has happened with me. The system has been very reliable for me, and you occasionally feel the brake assist with pre-sense as well as the braking force lightens up again once you are 'out of danger' as it were.

snakehips · Jan 2, 2014

I've never heard of issues like this but this is exactly the sort of thing I fear with ACC and so never specced it. I hope you figure out a fix before anything bad happens!

cemerson · Jan 2, 2014

There's nothing to be worried about really - it's an assist, not a 'do it all for you' system (although the effect is much the latter). It's there to help, but it doesn't absolve the driver from monitoring the situation and taking over when needed.

BZ888 · Jan 2, 2014

Yes, but without a warning tone, how do I know when to take over? If I take-over whenever a car in front of me brakes, that defeats the purpose of adaptive cruise.

adamss24 · Jan 2, 2014

Maybe it makes sure you're not taking a nap in there...what is world coming to ? Cars that park themselves, adaptive cruise control, auto lights, auto wipers,etc...soon one won't need a driving licence in order to drive a motor vehicle !

J6YAK · Jan 2, 2014

BZ888 said:
Yes, but without a warning tone, how do I know when to take over? If I take-over whenever a car in front of me brakes, that defeats the purpose of adaptive cruise.

If the car in front brakes hard YOU should react not the car, it's isn't auto pilot!!

snowfree52 · Jan 2, 2014

OP, do you have a manual or Stronic ?

manual, I'm not sure, but if auto the car should brake itself, Mine already did it and saved me from a big accident.

You should get your car checked by the dealer.

BZ888 · Jan 2, 2014

snowfree52 said:
OP, do you have a manual or Stronic ?

manual, I'm not sure, but if auto the car should brake itself, Mine already did it and saved me from a big accident.

You should get your car checked by the dealer.

I have S-Tronic. Its very strange. No warning tone. No pre-sense activation either.
I will speak to the dealer, but I already know what they'll say.

1. "Yes, thats normal" or
2. "You will need to replicate the problem so our Foreman can verify" or
3. "You should always monitor the road ahead"

I love the car. Just wish it would work correctly. Scarred the crap out of my Mrs the other day. She now doesn't want me to use adaptive Cruise when shes in the car!

yetirider · Jan 2, 2014

I'm not really surprised, your posts are kinda like saying i didn't have a clue whats going on in front of me..........

BZ888 · Jan 3, 2014

yetirider said:
I'm not really surprised, your posts are kinda like saying i didn't have a clue whats going on in front of me..........

You obviously don't understand what Pre-Sense is nor how the Adaptive Cruise System is marketed.
My skills as a driver are advanced. Never had one accident in 27 years. Owned many track cars. Find it very difficult to let these system manage the car. It goes against my intuition.

My argument is simple. If Audi proclaim to have Pre-Sense, Brake Guard and Adaptive Cruise and none of them work under certain circumstances, then the product does not deliver. I could have saved my self $6k of options.

cemerson · Jan 3, 2014

snowfree52 said:
OP, do you have a manual or Stronic ?

manual, I'm not sure, but if auto the car should brake itself, Mine already did it and saved me from a big accident.

You should get your car checked by the dealer.

Manual does the same, just have to be wary of gear changes. If the engine speed gets too low (eg, 40mph or something in 6th gear) then ACC will cut out. Just hold the clutch in as it's braking and it'll go right down to about 10mph before turning itself off.

Like I said, I've never had this problem, the car has always managed the braking perfectly well. I always hover over the brake when I think there's a chance I may need to take over but if I let the car sort itself out it always does. I've not had anyone brake really hard in front of me though. Try a bigger distance setting than 'the closest I can drive up the rear of the car in front' and it might be able to cope better?

BZ888 · Jan 3, 2014

Yeah, I might try Distance 2. But I don't know why pre-sense doesn't cut in...

Final 3Green Land · Jan 3, 2014

My A4 actually comes with a similar system; a pedal on the floor you place your foot on when you get a little close to the car in front...

It works every time for me!

If you have to rely on a system to brake for you, time you hung up your driving boots!

Wâ!

luadr1 · Jan 3, 2014

I wonder why one uses Distance 1 at 100km/h

lee_fr200 · Jan 3, 2014

Have you checked the mmi settings that pre sense and brake guard are on? As I know in some models it can be switched on or off, I'd also change the distance setting

Cockney Boy · Jan 3, 2014

First off all scan for fault codes and then book the car in to a dealer that can calibrate the system. Also make sure the mirror on the sensor is still intact as this can throw up nasties

Report back

pat15312 · Jan 3, 2014

Did you have traction control off? This turns off pre-sense. I can't say I've experienced the same problem as yourself; I have had the car brake to a complete stop on the motorway before when using ACC, definitely worth letting the dealer take a look.

constvoid · Jan 3, 2014

Although this is a 'me too' post, I've not had this problem either. I've had the pre-sense alarm go off a few times now, but to be honest I'm not conscious that it actually began braking itself - I'm far too concerned with getting my own foot on the brake when it happens.

You have to remember what ACC actually does - it attempts to drive a set number of seconds behind the car in front. Even at the default distance 3 it's only about 2 seconds apart. That's not enough time to brake to a complete halt at anything above town speeds - it's the equivalent of 'thinking time' so that it begins braking for a car slowing down normally or moderately heavily. If you were driving without ACC you'd be hard on the brakes as soon as you noticed that the car in front was braking heavily. With ACC it should be no different.

To the original poster - get pre-sense chcked out by the dealer, but don't assume ACC will always protect you from abnormal situations.

cuke2u · Jan 3, 2014

Does having the driving mode set to 'dynamic' have any effect upon the adaptive cruise?

Daveotto · Jan 3, 2014

BZ888 said:
..........My skills as a driver are advanced. Never had one accident in 27 years. Owned many track cars. Find it very difficult to let these system manage the car. It goes against my intuition.

My argument is simple. If Audi proclaim to have Pre-Sense, Brake Guard and Adaptive Cruise and none of them work under certain circumstances, then the product does not deliver. I could have saved my self $6k of options.

Can understand your frustration but surely if you had any doubts on the relaiability of these systems you should have tested these things out during an extended test drive before you purchased.

If in doubt why spec it in the first place.....IMHO cars are to be driven not to get in and be driven by...I seriously do not like all this new technology..in future I would suggest if you dont trust it dont spec it and save $6K and use the money for a taxi when you need to be driven rather than drive yourself!!!!!!

I would never spec ACC or Park Assist and would only ever consider an Auto if I done a lot of city driving, I can live without standard cruise control and only use it occasionally as came as part of comfort pack.

That said given the fact that you have had what appear to be significant issues I would go to Audi UK direct for answers if your dealer gives you any type of flippant response.

CraigI · Jan 3, 2014

Daveotto said:
Can understand your frustration but surely if you had any doubts on the relaiability of these systems you should have tested these things out during an extended test drive before you purchased.

If in doubt why spec it in the first place.....IMHO cars are to be driven not to get in and be driven by...I seriously do not like all this new technology..in future I would suggest if you dont trust it dont spec it and save $6K and use the money for a taxi when you need to be driven rather than drive yourself!!!!!!

I would never spec ACC or Park Assist and would only ever consider an Auto if I done a lot of city driving, I can live without standard cruise control and only use it occasionally as came as part of comfort pack.

That said given the fact that you have had what appear to be significant issues I would go to Audi UK direct for answers if your dealer gives you any type of flippant response.

Agree with this, some of these things are gimmicks that I would class as normal driving procedure, why you need help with that I'm not sure.

constvoid · Jan 3, 2014

CraigI said:
Agree with this, some of these things are gimmicks that I would class as normal driving procedure, why you need help with that I'm not sure.

Each to his/her own. In my case I chose the options I felt that would be most useful to me, and as I'd used cruise control extensively on the 8P, I saw ACC as the next logical progression. I'd be very unlikely to spec a car without it now, but as with my previous post, you do need to be aware of its limitations. It is after all a driver assistance/comfort option, not something to take over completely - we still have to wait a few years before that sort of thing becomes mainstream.

CraigI · Jan 3, 2014

constvoid said:
Each to his/her own. In my case I chose the options I felt that would be most useful to me, and as I'd used cruise control extensively on the 8P, I saw ACC as the next logical progression. I'd be very unlikely to spec a car without it now, but as with my previous post, you do need to be aware of its limitations. It is after all a driver assistance/comfort option, not something to take over completely - we still have to wait a few years before that sort of thing becomes mainstream.

Yes each to his/her own, but since I enjoy driving, I'd never want anything to take over elements of that for me.
I only use cruise as a way of not racking up speeding points, however I'm perfectly able to slow down and stop whilst doing so, keep within lane, and not roll into the car behind me when I'm stopped on an incline.

Perhaps when I'm a bit older and my driving deteriorates such that I might need driving assistance I'll change my mind but for now, less is more for me.

h5djr · Jan 3, 2014

CraigI said:
Yes each to his/her own, but since I enjoy driving, I'd never want anything to take over elements of that for me.
I only use cruise as a way of not racking up speeding points, however I'm perfectly able to slow down and stop whilst doing so, keep within lane, and not roll into the car behind me when I'm stopped on an incline.

Perhaps when I'm a bit older and my driving deteriorates such that I might need driving assistance I'll change my mind but for now, less is more for me.

I'm 66 and still enjoy my driving very much. I have normal cruise control on my existing Sportback but the only time I use it is to keep to the speed limit through road works and on my 300-400 mile drive across France/Belgium to get to Germany. In the road works ACC could be of use of often the car in front finds it impossible to maintain a steady speed. On the long journey it would save me having to switch off cruise control as I approach another car, especially if their is another car in the outside lane that I'm happy to let go passed me before I pull out to pass the slower car in my lane. As soon as the car in the outside lane is passed I can just pull out and the ACC will take me back up to my previous cruise speed with me having to engage the normal cruise control again. But I very doubt if I will use use it at other times, unless perhaps on a long motorway journey.

cuke2u · Jan 3, 2014

I think the OP asked a decent enough question without getting flamed for a system that should work as advertised. Some of the comments here are not particularly helpful...

Daveotto · Jan 3, 2014

cuke2u said:
I think the OP asked a decent enough question without getting flamed for a system that should work as advertised. Some of the comments here are not particularly helpful...

Agree - a reaonable question from the OP and some good debate and opinions but I dont think any of the posts on this thread have been over inflamatory, maybe a gas mark 1 or 2 comment or two compared to some of the comments on other threads recently....just my two penny worth

CraigI · Jan 3, 2014

cuke2u said:
I think the OP asked a decent enough question without getting flamed for a system that should work as advertised. Some of the comments here are not particularly helpful...

Note to self, consider the above point of view when going "off on one" irrationally about Apple products.
At least this discussion is on topic.

cuke2u · Jan 3, 2014

Unfortunately that's even further off topic. Strange though that I have already had two 'likes' for my post.

cemerson · Jan 3, 2014

BZ888 said:
Yeah, I might try Distance 2. But I don't know why pre-sense doesn't cut in...

I think pre-sense is generally designed for slower speeds than motorway driving, not sure.

steeve · Jan 3, 2014

Mmmm.
I'm not a luddite, but I would rather not have these 'safety' systems, adaptive cruise, lane assist etc etc. With every autonomous system there are conditions and circumstance where perhaps all the parameters may not be fully met.

How do you know when its going to work or not work? Perhaps people become reliant on them (like this gentleman) and wait for it to kick in, it might be too late when it all goes pear shaped. I wouldn't liken these new systems to ABS, that's very basic and just measures wheel speed differentials. But even then its a system that works after you have and not on its own like these others. This is not an assist feature the driver doesn't have to do anything, it works autonomously, ABS is an assist feature.

I see them as potentially dangerous and wonder how long it is before some one is either killed or ends up in court claiming they ran into the car in front or at the side because their car didn't brake or alert them.

Its my own opinion but the driver should be totally in control and not the car, if the car in front slows then the driver should react immediately and not wait for his Audi, BMW or what ever to do it for him. By that time it's going to be too late in an emergency.
So here we have a situation where BZ888 has a car brake suddenly and heavily in front of him and he didn't immediately react? He waited that split second for the car to do it for him? No warning tone? Mad, absolutely mad. I just hope that none of you out there are driving behind me and my family in your automated (?) vehicles. If I'm ever behind you, you can damn sure be certain I'm alert and ready to control my vehicle and keep a safe distance behind you even in an emergency.

cemerson · Jan 3, 2014

steeve said:
I see them as potentially dangerous and wonder how long it is before some one is either killed or ends up in court claiming they ran into the car in front or at the side because their car didn't brake or alert them.

I bet they prevent more accidents than they cause. There are enough warnings in the handbook anyway about how it's still the dirvers responsibility to monitor things and take over if necessary. I don't know about you, but if a car in front of me brakes suddenly, I'll be on the brakes regardless of whether ACC is on or not - and don't know any sane driver that wouldn't.

You see this 'mistrust' of technology everywhere at the moment, it's quite disheartening in my view. I think they are great systems, assists (not 'do it all for you'), and it's sad that people mistrust it all so much, they are missing out.

And yes, in my view, it does make you a luddite!

steeve · Jan 3, 2014

"I bet they prevent more accidents than they cause. There are enough warnings in the handbook anyway about how it's still the driver's responsibility to monitor things and take over if necessary. I don't know about you, but if a car in front of me brakes suddenly, I'll be on the brakes regardless of whether ACC is on or not - and don't know any sane driver that wouldn't."

Well BZ888 for instance?

cemerson · Jan 3, 2014

Well quite, not saying it won't or can't happen, but bad drivers will be bad drivers whether they have technology or not. The technology adds a huge benefit in my eyes, stops you creeping up on the car in front without noticing if they lift off on the throttle a bit, reacts faster than a driver ever could to a car stopping suddenly (and yes, faster than you even though you are apparently 100% alert all the time and never distracted by anything...). Maybe there is an error in the OP's system, maybe not - I know that the one in my car works, and ALWAYS warns when it has stopped control of the car with a chime and message in the instrument cluster - though it can be lost if you have music on, so maybe that's the case as well.

Daveotto · Jan 3, 2014

cemerson said:
You see this 'mistrust' of technology everywhere at the moment, it's quite disheartening in my view. I think they are great systems, assists (not 'do it all for you'), and it's sad that people mistrust it all so much, they are missing out.

And yes, in my view, it does make you a luddite!

I don't actually mistrust the technology....... I actually like driving my relatively expensive car and enjoy moving levers, presing pedals and turning wheels otherwise I would get a taxi

cemerson · Jan 3, 2014

So if you have to drive 100 miles on the motorway, you enjoy having to constantly finely adjust your throttle setting with an aching foot that has to hover in the same position for a couple of hours?

It's ridiculous to suggest that just because someone has these options and assists specced, it means they somehow can't drive the car when they want to, and use the assist systems when it makes sense to.

They do all have off switches you know!

Daveotto · Jan 3, 2014

cemerson said:
So if you have to drive 100 miles on the motorway, you enjoy having to constantly finely adjust your throttle setting with an aching foot that has to hover in the same position for a couple of hours?

It's ridiculous to suggest that just because someone has these options and assists specced, it means they somehow can't drive the car when they want to, and use the assist systems when it makes sense to.

They do all have off switches you know!

Agree there are times when the technology is good and I use standard cruise control when driving on French motorways for example, but in general leave the car in dynamic and just have as much fun as possible driving it at all times.

Suppose thats where the grey area is...... using techniology when its useful v using at all times 'cos its there

cemerson · Jan 3, 2014

Well that's just the driver's choice. Some people enjoy driving, some people find it boring... they'll use the tools that are there when they want to. Simple as that! I don't moan about people who choose not to have assist systems because they enjoy driving (I do moan about people who moan about technology because it's 'change' and is creating 'bad drivers' which is a load of nonsense of course), so I'm surprised some people moan about the availability of the technology just because they prefer not to have it!

CraigI · Jan 3, 2014

cemerson said:
Well that's just the driver's choice. Some people enjoy driving, some people find it boring... they'll use the tools that are there when they want to. Simple as that! I don't moan about people who choose not to have assist systems because they enjoy driving (I do moan about people who moan about technology because it's 'change' and is creating 'bad drivers' which is a load of nonsense of course), so I'm surprised some people moan about the availability of the technology just because they prefer not to have it!

How about you moaning with regards to Apple technologies?
Double standards or what?

cemerson · Jan 3, 2014

Apple I consider damaging to the industry I work in, and their practices and ideologies are bad for everyone, and AFFECT everyone by reducing consumer choice, so I consider them to affect me, my industry and i'll continue to criticise them for it!

In any case, I don't tend to comment on Apple stuff unless asked my opinion on it, or the topic is directly about it (eg, the in-car integration with mobile OS thread the other day). Or someone else is talking nonsense about it!

Adaptive Cruise Fails to Brake to a Stop - Nearly Hits Car!

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