ACC/Front Assist

[Websta24]

Quick question to see if mine is working properly....

In a situation of driving behind a car in a 30/40/50 zone using ACC, The car in front pulls off into a box junction (turning right) and the front assist jumps in and slams the anchors on?!

Can anyone else comment on this? For me it seems far too sensitive and it should realise a car has moved out of the way but it seems to still be picking up the other vehicle!

It scared the sh!t out of me when it did it first time out.

Also, the big red symbol on the dash and audible ping that occurs when your driving through a gap is also quite frustrating!

The latter i think it normal, but am i right in thinking i should go back to VW and ask if its configured correctly?

Thoughts would be most appreciated

[fredgroves]

No it can have all sorts of funnies.

I've had my Mk7 GTD for 18 months and its sh!t me up maybe a dozen times in that time.

I've had:

1) Car in front turning left/right with me following at a safe distance and not needing to brake, PING! Anchors on.

2) Foil crisp packet in the road, PING! (and the warning brake dab)

3) Coming off of a long motorway slip road, motorway full of stationary traffic but slip road clear, PING and anchor up.

And a few others, but #1 is the top cause.

It uses a radar sensor together with a prediction algorithm about closing speeds and intersection probability, together with seeing if the driver has made any adjustments to suggest he/she has seen the impact. If you don't back off the gas or brake or steer AND it predicts impact, it will trigger.

Unfortunately the path prediction is based on radar returns, which is not entirely accurate and can be fooled by a fake radar picture from interference or a target that reflects a bigger amount of signal (in the same way military radar decoys work) than is normally expected.

All of this can in itself be dangerous, when vehicles behind you aren't expecting you to slam on the anchors (any more than you were expecting it to happen, because the road is clear).

I've been sworn at before when it happened... (scenario #3 above I almost had a Jeep rear end me)

[Mk7-GTD]

I have seen a video from the UK here where a person was prosecuted for causing an accident by jamming on their brakes so that the car behind would run into them(the car behind had a camera)

Now what if the car brakes itself and someone runs into you, who would be held responsible then and how could you prove it was the car and not you that braked?

I take it that this can be switched off?

[p3asa]

I have seen a video from the UK here where a person was prosecuted for causing an accident by jamming on their brakes so that the car behind would run into them(the car behind had a camera)

Now what if the car brakes itself and someone runs into you, who would be held responsible then and how could you prove it was the car and not you that braked?

I take it that this can be switched off?

Good question.
If you turn it off though would your insurance be void without telling them as this is no doubt a safety feature and may help bring down the premium rate? And on the flip side would it increase your payments if you did tell them you had turned it off?

Maybe something would be logged on the car that it was the car that flung on the brakes.
Its actually quite frightening when it happens unexpectedly when you are happily singing along to a song, totally oblivious. Its happened to me a few times and I must admit the first time I was more inclined to assist it with the brakes as I thought "I must have been going to hit something otherwise the car wouldn't have done that" It was just me behind a bus and the bus pulled in and I was going to go round it.

What I have noticed though is if I sit with the ACC selected on my MDF when I'm just driving around the 30 / 40 roads, its more prone to doing it. Could just be a coincidence though.

[Sokkia]

Not sure you can be prosecuted for hitting the brakes. Always believed whether correctly or not that if you stop, no matter how suddenly and get rear ended its the following cars fault for not being a safe stopping distance behind you. I used to work in the dreaded car insurance industry, all be it many years ago and that's my understanding. Who is to say that you weren't reacting to a potential incident that didn't materialise. How many times have you seen kids come barrelling down a drive on a bike or something and look like they will go into the road, only to stop bang on the kerb line cool as you like.

Have had the car do the emergency stop once so far in 2 months of ownership. As I pulled out to pass a stationary bus, not sure it was the bus as was alongside it more likely the oncoming traffic. Almost altered the upholstery pattern in an unwanted way.

[fredgroves]

I was quite surprised just how quickly a Mk7 GTD can stop at 30mph...

As for would it be possible for forensics to tell... of course! Your car logs all sorts of driving data and routinely the police seize the data for analysis and can tell about speeding, braking and all sorts leading up to a crash.

Would it be your fault? Well, probably, the other option is to sue VW.... I don't think its happened yet but as cars get more automated, eventually it will for sure!

[Sokkia]

Would it be your fault? Well, probably, the other option is to sue VW.... I don't think its happened yet but as cars get more automated, eventually it will for sure!
[/quote]

I still don't see it being your fault if the driver behind runs into you. What's the difference between this and an actual incident requiring an emergency stop. The driver behind should be an adequate distance behind so as to not run into the car in front in an emergency. Hence Tailgating being an offence or as good as these days and subject to on the spot fines.

[fredgroves]

Is the "2 second rule" actually enough to react and stop in if you are following a Mk7 that applies maximum braking with no warning?

Based on my sudden stop I had, I'd say no...

I thought i'd actually hit a parked car, thats how fast it stopped!

[Sokkia]

By no means an expert but the Highway code says something like you should be an adequate distance from the car in front to be able to stop in the available clear distance between cars. Think the 2 second rule is more for higher speed roads anyway and is merely a guide line. Various cars different stopping distance etc. etc.

Not wanting to stray onto another subject, but tyres (don't mention Bridgestones on here  ), reactions and obviously speed make a big difference to the stopping distance. If a kid stepped out in front of you and the car slammed on and you then got rear ended by the idiot behind and subsequently hit said Kid, what would the local plods view be? Whose fault is the kid got run over? Now if you maliciously slam on then maybe a different story, but ACC kicks in or you physically genuinely brake for a perceived hazard surely the person behind is at fault. After all the ACC kicks in for what it deems is a perceived hazard, whether rightly or wrongly same mistake us humans can make really.

I know I would strongly argue any case if I was smashed from behind.

[fredgroves]

Just something I found on the internet (not been able to verify it) but... two bits of quoted case law (on which the UK legal system works)

In Gussman v Gratton-Storey the Defendant applied her brakes violently in order to avoid hitting a pheasant running across the road. The driver behind was unable to stop and collided with the Defendant’s vehicle. The Defendant was held liable so in this case the sudden stop was in effect held to be unreasonable. The lead driver was held liable in this case.

Blyth v. Birmingham Waterworks Co. (1856), was a landmark ruling:

Holding and Rule: Negligence is determined by a reasonable person standard. A person is not negligent if his conduct and precautions conform to the standard obeyed by a prudent or reasonable person.

A reasonable person cannot be held liable for an unforeseeable event. Negligence is an objective standard and has nothing to do with a party’s subjective state of mind.