ACC failed.

[Fatso]

Last week I was driving down a dual carriageway using the ACC when I came up on 2 lanes of much slower moving traffic and the car completely failed to slow down automatically and carried on at 70mph. Luckily, with an emergency manual override and a very conveniently situated slip road, I was able to avoid a collision.

 

Before this, and after (under very much closer observation!), the ACC worked perfectly.

 

Has anyone else had any issues with this?

 

I did consider the ACC to be one of the best things about my Superb, especially on my commute in busy traffic, but I don't trust it now.

[xman]

Was the sensor covered in grime as you eluded it in another thread?

 

The problem with technology is you can build in failsafes, backup strategies etc etc but there will always be something that either they didn't consider or regarded as impossible/highly improbable or didn't adequately test for. 

 

Happens all the time and sadly we often have to learn via tragedy.

 

Tesla learnt in the early days after someone died that their systems were far from perfect (even though they still blamed the driver). Who knows? Many (fatal) accidents may have already happened where technology contributed, from a failed throttle sensor to ACC failure to spurious software glitch. In most cases, investigators and police will simply put it down to "driver error"

 

Expect much more of this as governments/investors enthusiastically promote full autonomous driverless vehicles.

[Fatso]

My car wasn't particularly dirty when this happened, and as I said it worked perfectly before and after this one isolated incident i.e. on the same journey without getting my car washed in the meantime.

 

I do actually make sure the sensor is clean even between car washes.

[daveo138]

On Wednesday, I drove 100 miles to Hampshire and didn't use cruise control once, such is my dislike of ACC compared to 'normal' cruise control. 

 

On the return journey, I was giving a lift to a colleague and was demonstrating the ACC and how it would slow down when it saw traffic ahead. At one point, I noticed that the traffic ahead was braking, but the car carried on until "BRAKE" suddenly appeared on the display at exactly the same moment that I stamped on the brake pedal. 

 

Neither of us were impressed, and I didn't use ACC for the rest of the journey. 

[RickTT]

Did you have the radar range on the closest sitting ?

[xman]

Its a shame you can't switch the adaptive bit off but I fully understand why Skoda wouldn't allow that.

[penguin17]

1 hour ago, xman said:

Its a shame you can't switch the adaptive bit off but I fully understand why Skoda wouldn't allow that.

Perhaps so that you don't forget what mode it's in and inadvertently drive up someones a55 thinking that the ACC will brake eventually? 

[Fatso]

I did have the range set on it's closest setting. The thing is this problem was a one off, the ACC had worked before and did so afterwards.

 

I thought you could change from ACC to standard cruise control with the button on the bottom of the CC stalk? (I haven't tried this).

[nicknorman]

ACC doesn’t have a very long range, and doesn’t detect stationary traffic ahead. So it’s fine if you are following an in-range car ahead, but if you come up behind cars doing 20 when you are doing 70, it’s unlikely to be able to slow down in time. And if they are stationary it definitely won’t.

 

No, you can’t turn off the “adaptive” bit.

[vfrvrs]

Yes it's Reactive not Proactive 

[xman]

Who protects you on your way?

A whole phalanx of new assistance systems previously the domain of higher vehicle classes is available for your enhanced safety. The ŠKODA SUPERB is fitted with Electronic Stability Control (ESC), including a Multi-Collision Brake as standard. 

In EU countries, the following safety features are fitted as standard: Front Assist with City Emergency Brake, electronic Tyre Pressure Monitoring, seven airbags, and XDS+, an advanced electronic differential lock function. 

 

 

Front Assist:

 

https://www.euroncap.com/en/ratings-rewards/euro-ncap-advanced-rewards/2013-skoda-front-assistant/

Edited 13 January, 2018 by xman

[FelisBengalensis]

Very occasionally I have had the ACC ‘lose lock’ on vehicles ahead and surge ahead.  It usually occurs in slow traffic and is completely random.  Rain and dirt is not the cause as it does it in clear weather with a clean car just as much as any other time.  I have no idea why it does it but I now never have the ACC set closer than two bars - which are speed sensitive as the faster you go, the longer the gap ahead becomes - in normal traffic and three in slow.

 

It definitely misses stationary vehicles but when lock is lost it is always in traffic and had a lock moments before.  Sometimes it gains lock again and slams on the brakes, but I have usually got there first.  The system does not engender trust - which it probably shouldn’t - which makes me wonder why it’s there at all at times.

Edited 13 January, 2018 by FelisBengalensis
Typo

[rtj70]

5 hours ago, Fatso said:

I thought you could change from ACC to standard cruise control with the button on the bottom of the CC stalk? (I haven't tried this).

That switches from ACC to speed limiter - you set a speed and cannot go faster no matter how much you press the accelerator.

[MorrisOx]

11 hours ago, FelisBengalensis said:

The system does not engender trust - which it probably shouldn’t - which makes me wonder why it’s there at all at times.

 

Spot-on. This isn’t meant to be any kind of autonomous system, merely a stress-reliever on longer journeys. Nevertheless, in terms of safety, the distance control needs to be better than this and it sounds to me like there should be an on/off choice for this aspect of the system because it adds a while load of complexity to the use of a control which is meant to be simple to use. Presume it disengages the moment you brake, though?

 

Suspect there are some pretty basic warnings about usage in the handbook because this is a million miles away from Tesla’s supposed autonomy. Even that is far less sophisticated and able than the PR stunts would have us believe.

Edited 14 January, 2018 by MorrisOx

[MorrisOx]

13 hours ago, FelisBengalensis said:

Very occasionally I have had the ACC ‘lose lock’ on vehicles ahead and surge ahead.  It usually occurs in slow traffic and is completely random.

 

The other point to bear in mind about ACC is that it doesn’t work below 15mph, and I suspect the system will begin to struggle as it approaches that threshold. So it will always ‘lose lock’ in motorway crawls - though it should tell you when it disengages. If it doesn’t, that’s a poor design.

Edited 14 January, 2018 by MorrisOx

[Fatso]

46 minutes ago, MorrisOx said:

 

The other point to bear in mind about ACC is that it doesn’t work below 15mph, and I suspect the system will begin to struggle as it approaches that threshold. So it will always ‘lose lock’ in motorway crawls - though it should tell you when it disengages. If it doesn’t, that’s a poor design.

 

My car has DSG and ACC will bring the car to a stop and set off again in traffic jam crawls, often below 15mph.

Edited 14 January, 2018 by Fatso

[rtj70]

1 hour ago, MorrisOx said:

The other point to bear in mind about ACC is that it doesn’t work below 15mph

 

It will if you have both DSG and lane assist because you can set it and it will operate as Traffic Jam Assist (that's what they market it as) and it will follow the car in front, keep in lane, stop/move again, etc.

[MorrisOx]

I don’t think that’s ACC at work - Skoda states quite clearly that ACC can ‘...maintain a constant distance to the vehicle in front at speeds of 15mph or more’.

[rtj70]

Yes it is using ACC - how else do you think it detects the distance to the car in front

[MorrisOx]

But not on its own - ACC alone doesn’t have that functionality according to Skoda?

[Bud]

The systems will probably not be built upon safety critical software and as such there will be occasions when a set of circumstances lower the performance of the system.  

 

This is exactly as we see with humans, many road traffic collisions are due to human error and we just move on but we cannot accept that computers may also have errors even though in most cases they outperform humans significantly.

 

This is the significant hurdle to automation as humans think they know best and can react better.  Until we accept automation and then industry fully develop safety critical software for road vehicles there will always be those areas where a glitch from a sensor degrades system performance.

 

It is required to meet certification in aviation design , see SAE ARP4754 and DO-178 for a bit of light reading.

 

In the meantime be aware and monitor your vehicle's response and performance as you are required to by law.

 

[daveo138]

5 hours ago, rtj70 said:

 

It will if you have both DSG and lane assist because you can set it and it will operate as Traffic Jam Assist (that's what they market it as) and it will follow the car in front, keep in lane, stop/move again, etc.

 

 

I don't have lane assist, just ACC and DSG.  It works down to 0mph and when stationary says something like "ACC ready" in the display. When the traffic starts moving, just tap the accelerator and it's off again. 

[Alan_P]

Does this help?

 

[FelisBengalensis]

Traffic Jam Assist and ACC both use the same radar to maintain a distance or speed from a vehicle ahead.  If the road is clear it will hold the speed, if not it holds a distance at the current traffic speed if that is less than the speed setting.  Traffic Jam Assist will not function without the ACC being on (whether active or not).  Lane Assist uses a camera and not the radar.

 

To be honest, if the systems aren’t predicatably reliable then I would rather not pay for them (whether part of a standard spec or not) and continue to use my own judgement as required by the Highway Code 

Edited 14 January, 2018 by FelisBengalensis

[Bud]

1 hour ago, FelisBengalensis said:

Traffic Jam Assist and ACC both use the same radar to maintain a distance or speed from a vehicle ahead.  If the road is clear it will hold the speed, if not it holds a distance at the current traffic speed if that is less than the speed setting.  Traffic Jam Assist will not function without the ACC being on (whether active or not).  Lane Assist uses a camera and not the radar.

 

ACC gap is actually time based, think of the 2 second rule but where you could add any extra word if you are worried or delete a few if you are macho. Thats the stripes between the cars but funnily enough most drivers think in terms of distance rather than time. I firmly believe that's why we have a load of  middle lane hoggers who do not recognise that although they are going at 70ish the time gap between them and the car on the inside may be minutes although only a hundred metres

Quote

To be honest, if the systems aren’t predicatably reliable then I would rather not pay for them (whether part of a standard spec or not) and continue to use my own judgement as required by the Highway Code 

 

So get rid of your DSG, your 4x4, your ABS, your DSC and that's just on the SIII.  I would just throw away the X6 and say no I want a Ford Anglia with 4 speed manual box and manual choke, I can manage all the other stuff