Front Assist

[Cruiser]

Yesterday I was driving in a queue at 40mph about 3 car lengths of clear road behind the vehicle in front when the collision warning suddenly activated. Anyone else had this happen, and can anything be done about it? I am concerned that if this can happen, the emergency braking might kick in too. Could it be caused by falling leaves?

[SoupDragon]

Yes, three times in three years in my Fabia. By that I mean the brakes activated momentarily for no apparent reason. They operated a couple of times for obvious reasons and I occasionally received a dashboard warning for obvious reasons. I was concerned that at some stage the brakes would come on for no apparent reason and cause the following car to run into me and then claim that I did it on purpose to cause a collision so that I could make a claim. I asked the garage where I bought the car if automatic activation was recorded in the OBD and was told that it was not recorded. I surmised that the activations were caused by an empty aluminium can rolling across the road and  a slightly raised drain grate. I had no idea about the third activation, there was nothing in the road at all. The car never came to standstill but just experienced momentary heavy braking. 

[Guest]

Only a few times on the Octavia but only once where I found no reason. Leaves, debris, insects hitting the sensor? I dunno.

 

What worries me more tho is on the many occasions I think the warning should appear and it doesn't.  Other than drive towards a brick wall at 20mph and if you hit it...     I'm not sure how you can tell the system is working? 

[Felvo]

The workshop has an option to lower the sensitivity whilst still working in normal parameters, yours sounds hyper-sensitive.

[Russ77]

If the sensor picked up that the car in front was travelling slower than you and that you were maintaining you speed the warning would kick in.

 

If you were 3 car lengths let's say 15ft per car so 45ft, at 40mph you're covering 58 feet per second so FA would justified to kick in.

 

In reality, if the car in front had come to a sudden stop you may not have had time to stop.

[Gabbo]

The system should not react to leaves but there were several cases of Nissans (if I remember correctly) reacting to reflective objects that were moving which the system interprets as an object travelling quickly in an oncoming direction.

 

 

An easy way to test the system without causing any damage is to get a person sized stack of cardboard boxes & glue the front facing side with aluminium foil.

If you hit it, the only damage is to the box.

If you watch the NCAP reviews of the Tesla autopilot system this is exactly how they test it..

[Cruiser]

Thanks for the prompt replies people. If it happens again I'll disable the function. To me the Oct3 feels like a cheap car compared to the Oct 2 it replaced, as if they've paid for the fancy electronics by skimping on the build and suspension. Might trade it in for a Honda.

[themanwithnoaim]

26 minutes ago, Cruiser said:

To me the Oct3 feels like a cheap car compared to the Oct 2 it replaced, as if they've paid for the fancy electronics by skimping on the build and suspension. Might trade it in for a Honda.

Yep, I was in a 1.4 TSI ELEGANCE (SE L predecessor) for 3-1/2 years, it feels & looks a far more comfortable place than it actually is.

 

The rear tourture suspension setup throws up so many cost savings on sound proofing & build quality, any of the IRS models are so much nicer.

[skd12]

Mine has unexpectedly activated several times in the past 3 years.

Once in heavy snow with a van diagonally in front of me - I figure the car interpreted the van as coming across my path, once for a crisp packet when pulling away from some lights which nearly resulted in the car behind ramming me - that would have been fun to explain to the insurance company, and one recently when there was a bus in the bus-stop - I think the car misjudged my trajectory as it was tight but I had space to pass safely.

[Gabbo]

This highlights well the limitations of front-assist or ACC when it isnt explicitly linked with lane recognition.

The system can only determine where the car is going based on steering wheel angle sensor input.

If the road ahead of you turns to the left or right the system will assume the cars infront are turning into your lane & react as it cannot know you will turn the Wheel in the same direction a few seconds later.

 

The same is present when you are navigating a small gap or e.g. roadworks with narrow lanes, a small steering correction can trigger the system.

[Cruiser]

I've now had my Octavia 3 for about 6 weeks. In that time the collision warning has flashed up three times for no reason, the last accompanied by heavy braking, albeit only for a moment, thankfully. This is pretty alarming so I'm now disabling the system, but I have to do this on each start-up since it enables by default. Suggestions?

[PetrolDave]

11 minutes ago, Cruiser said:

I've now had my Octavia 3 for about 6 weeks. In that time the collision warning has flashed up three times for no reason, the last accompanied by heavy braking, albeit only for a moment, thankfully. This is pretty alarming so I'm now disabling the system, but I have to do this on each start-up since it enables by default. Suggestions?

When you see the red warning appear, just press the right hand button on the steering wheel (assuming you have a MFSW) this will cancel the warning and stop any action being automatically taken so you can take any action needed yourself. If you don't have an MFSW just tapping the brake pedal briefly will have the same effect.

 

In my experience it is prone to alarm when it thinks the vehicle in front is either slowing faster than you are reacting or is turning out of your lane slower than it likes.

Edited 6 October, 2018 by PetrolDave

[Broctoncf]

On 18/09/2018 at 20:19, Cruiser said:

Yesterday I was driving in a queue at 40mph about 3 car lengths of clear road behind the vehicle in front when the collision warning suddenly activated. Anyone else had this happen, and can anything be done about it? I am concerned that if this can happen, the emergency braking might kick in too. Could it be caused by falling leaves?

Yes a couple of times on my 65 plate Fabia, i felt that i was at a very safe distance.

 

Steve.

[Russ77]

Well it's safe to say Front Assist didn't come to the rescue of this pigeon yesterday afternoon .......

 

 

[KevC_Derby]

My ears hurt....

[silver1011]

The momentary braking is the car warning you. It jabs the brakes and beeps to alert you, if you don't take over the braking manually, whilst it still sees the risk, then it will brake again, and harder, and for longer.