Possible stupid question - ACC

[markytop]

As per title I realise in advance this might be a stupid question, but I'm going to ask anyway. When using Adaptive Cruise Control and it slows you down, do the brake lights come on?

 

Was using it a lot on a long motorway journey over Easter, and noticed that as it first picks up the vehicle in front, there is what feels like a brief tap of the brakes, and just wondering if it is lighting the brake lights because on a virtually empty motorway I had it set on a large gap, but didn't want people thinking that I was flying up behind trucks, tapping the brakes, then pulling out into the next lane like someone who couldn't see past the end of the bonnet

 

 

Edited 24 April, 2017 by markytop

[Gizmo]

Yes it puts the brake lights on, but not when it slows down slightly as you described. 

[RickTT]

Yes.. it puts the brake lights on... same as on the VW passat also... when we went to Holland last year, my mate in his Passat, we both commented on how often the brake lights flick on and off when cruising..

[penguin17]

Also applies the brakes (lights on) going downhill as opposed to regular cruise control which will allow gravity to take over and allow the car to go over the preset speed. 

[Mickey43]

Brake lights also stay on when automatic handbrake is engaged.

 

Noticed this when in front of a truck the other day and i could see the reflection

[Whaty]

I think it's a good question, I'm embarrassed to admit that I hadn't even considered this......

[Coops]

I don't think it uses the brakes all of the time.

 

I had my bike rack on the other day and could see the brake lights reflecting on the bikes, but when using ACC I could tell the car was slowing but the brakes weren't being applied.

 

 

[facet edge]

This crossed my mind as well when I was behind a Merc who's lights were flicking on regularly.

I do find that it is difficult to keep up a smooth progression with the ACC, a number of times I've found myself 10mph slower than I want to go because out has matched the speed of the car in front. I know you can override it by pressing the accelerator but if you're going to do this you may as well be driving without ACC. 

When driving manually, if a car is coming up in the outside lane I ease off and let him clear and then pull out. The ACC will continue at the same speed and then slow behind the car in front which then means you have to accelerate from a lower speed.

[BillyJim]

2 hours ago, facet edge said:

I do find that it is difficult to keep up a smooth progression with the ACC, a number of times I've found myself 10mph slower than I want to go because out has matched the speed of the car in front. I know you can override it by pressing the accelerator but if you're going to do this you may as well be driving without ACC. 

The trick is to turn your indicator on after seeing that ACC has detected the vehicle in front. This will delay ACC trying to match the speed of the car in front. It will still slow you (much quicker) to match the speed of the vehicle in front if you are getting too close and still haven't moved out.

[markytop]

Thanks for all the answers everyone, I might mount my go-pro on the back and see what happens in what situation to make sure. Sounds like a project for a bored Sunday morning

 

Does anyone know if the optional higher speed version of ACC (the one where it works up to 210kmh, rather than 160kmh) is more sensitive or forgiving?

 

I saw it as an option when ordering mine, but at the time decided that at those speeds I would rather be in control myself, but now I have the car and find it so effortless, I can easily see myself sitting at more than 160kmh and wanting the functionality of ACC. (Before anyone complains, I live in Luxembourg and unrestricted German Autobahns are available about 10 min from where I live)

 

Could it be activated with VCDS? Although it was a €300+ option which would seem to suggest some extra hardware involved?

[facet edge]

1 hour ago, BillyJim said:

The trick is to turn your indicator on after seeing that ACC has detected the vehicle in front. This will delay ACC trying to match the speed of the car in front. It will still slow you (much quicker) to match the speed of the vehicle in front if you are getting too close and still haven't moved out.

That's fine as long as the outside lane is clear but when there is a car coming up on you you cannot put the indicator on as that would impede the the car behind. Easing off would give me enough room but the ACC just drags me towards the car in front and then slows down.

[Gizmo]

31 minutes ago, markytop said:

Could it be activated with VCDS? Although it was a €300+ option which would seem to suggest some extra hardware involved?

 

It uses a different radar sensor, VCDS cannot change the speed settings. 

[daveo138]

4 hours ago, facet edge said:

 

I do find that it is difficult to keep up a smooth progression with the ACC, a number of times I've found myself 10mph slower than I want to go because out has matched the speed of the car in front. I know you can override it by pressing the accelerator but if you're going to do this you may as well be driving without ACC. 

When driving manually, if a car is coming up in the outside lane I ease off and let him clear and then pull out. The ACC will continue at the same speed and then slow behind the car in front which then means you have to accelerate from a lower speed.

 

 

This is is why I dislike ACC and find myself using it very infrequently, as I am frustrated whenever I use it. 

 

Also, with 'normal' cruise control, if a car is coming up in the outside lane, you can often leave cruise engaged and time your overtake to coincide with the other car coming past. With ACC, it will have braked. 

[facet edge]

10 minutes ago, daveo138 said:

 

 

This is is why I dislike ACC and find myself using it very infrequently, as I am frustrated whenever I use it. 

 

Also, with 'normal' cruise control, if a car is coming up in the outside lane, you can often leave cruise engaged and time your overtake to coincide with the other car coming past. With ACC, it will have braked. 

I did find it interesting to realise how much I  vary the speed to acheive smooth progress. It's something you do automatically, although watching some other drivers it's obvious they don't think so far ahead.

[2slo]

A light push on the stalk to disengage the ACC when you need to overtake smoothly (or when traffic slows you down) followed by a pull back to resume when the road clears. I used it on a long journey last weekend and found it worked well.

[Bud]

It is not quite as smooth as I expected maybe I should open the gap a little to increase the buffer but I do like the fact that it will brake to a standstill and accelerate away, by cancelling the system you may as well have normal CC.  

 

To stop the brakes coming on, especially when passing a middle lane hogger, you could add a little gas, not to accelerate but just to take control as the sensitivity is sometimes too keen, there is a subtle change in the shade of the car symbol when you override the system, not from filled to unfilled as in the pic but it remains filled but tones are less bright.

 

The other point might be that you do need a little oomph to prosecute the overtake and the interventions gets you past the obstruction sooner than just on ACC.

 

Did 125k miles in a Mondeo with ACC and the DSG does make it more useful however, I have only done 900 miles so far and still require a little more time to understand how it will react, especially in different gearbox modes.

 

 

[ukgnome]

did 2,000 miles around France recently and about 1,000 around the west country much of the driving was done using ACC and it worked great, especially in France as it took me an age to spot the French speed cameras.

 

I even use it locally at 30mph due to an annoying bit of average speed camera on a local road.

 

I find you feel it lag when it gets too close to the car in front, but signalling overrides this back up to the set speed without using pedals.

 

With the lane assist function (which freaks out the family when the car drives itself round the corner) it usually means I can drive an extra hour or two before I get tired or my body cramps from being in one position for too long

[wooyay]

The ACC is brilliant compared to normal cruise control but don't always assume it'll do the correct thing. This evening I was in a traffic queue using the ACC when the car in front turned off which caused my car to start accelerating briskly towards the stationary vehicle in front. I had to manually brake hard to stop the car - it seems the radar had become blind to what was in front and wrongly assumed it was open road!

[starfighter]

3 hours ago, ukgnome said:

With the lane assist function (which freaks out the family when the car drives itself round the corner) it usually means I can drive an extra hour or two before I get tired or my body cramps from being in one position for too long

Your family are right to freak out. That is a safety aid and not meant do do the actual driving. The fact that you can do the extra hour should be telling you that you are not paying attention. A classic case of safety system reliance increasing danger. 

 

Yes, I do use ACC but find I am usually thinking well in advance of it. 

[BillyJim]

4 hours ago, wooyay said:

The ACC is brilliant compared to normal cruise control but don't always assume it'll do the correct thing. This evening I was in a traffic queue using the ACC when the car in front turned off which caused my car to start accelerating briskly towards the stationary vehicle in front. I had to manually brake hard to stop the car - it seems the radar had become blind to what was in front and wrongly assumed it was open road!

ACC will not register a stationary object unless it was previously moving. As the car in front wasn't moving it didn't detect it. Your example is specifically mentioned in the user manual...

 

Stationary vehicles

The ACC does not detect stationary objects! When a vehicle detected by the ACC turns or sheers off and there is a stationary vehicle in front of this vehicle, » Fig. 204 D - the ACC does not respond to the stationary vehicle.

In such cases, take over the steering and stop the vehicle by applying the foot brake. 

 

You're not the only one to get caught out. The day I collected my new car from the dealership I drove onto a dual carriageway and tried out the ACC. I thought it was great that it slowed to a stop at tailback from roadworks, then crept forward following the car in front, until that car moved out and left about 300 yards of open road which resulted in the ACC doing a kamikaze charge towards the cones. Lesson learnt!

Quote

Just because something doesn’t do what you planned it to do doesn’t mean it’s useless. Thomas Edison

 

[wooyay]

6 hours ago, BillyJim said:

You're not the only one to get caught out. The day I collected my new car from the dealership I drove onto a dual carriageway and tried out the ACC. I thought it was great that it slowed to a stop at tailback from roadworks, then crept forward following the car in front, until that car moved out and left about 300 yards of open road which resulted in the ACC doing a kamikaze charge towards the cones. Lesson learnt!

 

Now you mention it I do vaguely remember something along those lines, but that part of the manual was probably pushed out of my brain by more important things such as how to change the ambient lighting or similar. 

[freelunch]

1 hour ago, wooyay said:

... more important things such as how to change the ambient lighting... 

Ha! Those pages are dog-eared in my manual. My wife keeps searching for how to turn on the disco lighting! 

[FloatingBrick]

I've only had my car for 1 month and already done 4k miles, and use ACC regularly. To start with I didn't like it (compared to normal cruise control), but now I've adapted my driving style and forward planning around ACC I have to confess that it works mostly fine. There are three things I've done to make ACC perform better for me... 

 

1) Set the ACC distance setting on the dash display to the first or second closest line (this stops the ACC braking too early which allows more time to plan lane changes) 

 

2) Set my Drive Move on the infotainment screen to 'Individual' then changed the ACC setting to 'Sport' (this allows the car to accelerate a bit quicker when pulling out to overtake a slower vehicle in front, plus the 'Individual' mode stays enabled every time you switch the car on and off so you don't need to keep resetting it at the start of every journey) 

 

3) Switch the dash display to show the cars digital MPH readout when you use ACC (you can then see the speed gradually decreasing as the ACC is slowing the car down long before you realise)

 

I've come to realise that whilst ACC is frustrating at times, it is actually quite clever compared to normal cruise control. I used to have to keep frequently activating/deactivating my previous cruise control, or tapping the speeds up and down to suit the traffic flow (especially in heavier or busier traffic), whereas ACC does all this for me.

 

Hope this helps

[CheshireBumpkin]

On a virtually empty motorway it's fine, but then so is normal cruise control generally.

 

To be honest, I find 'managing' any sort of smooth progression with ACC to require just as much thought and intervention as driving without it, if not more. From a personal perspective I think it's more trouble than it's worth.

 

It's a promising start, but I suspect many of us use it because 'it's there' and 'we can', rather than it being of any great benefit. If I had to pay for it as an option it's not a box I'd tick.

[daveo138]

28 minutes ago, CheshireBumpkin said:

On a virtually empty motorway it's fine, but then so is normal cruise control generally.

 

To be honest, I find 'managing' any sort of smooth progression with ACC to require just as much thought and intervention as driving without it, if not more. From a personal perspective I think it's more trouble than it's worth.

 

It's a promising start, but I suspect many of us use it because 'it's there' and 'we can', rather than it being of any great benefit. If I had to pay for it as an option it's not a box I'd tick.

 

I totally agree. 

 

I've had normal cruise control for years and have used it all the time. 

 

I now find that I'm not using ACC, because it is more trouble than it's worth.