MK7 Golf TDI - Front Assist Question

[aashankhan]

Hello,

I purchased a MK7 Golf TDI last year. Last week I had an accident with the car where I hit another car on the side head on. The speed of my car was less than 10 mph.

The question that I have is that the front assist never came on although it was a head on collision. One of my friends mentioned that these systems only get activated after a certain speed. does anyone have any information on it?? Should I contact VW and complain that it never activated??


Thanks

Aashan

[itavaltalainen]

As I understand it the other car came from a 90 degree angle and was not ahead of you, sensor may not have had enough time to pick up on it, or it thought it was a solid object (like a wall).

The front assist has 2 modes:
City emergency braking which is active below 30km/h, so approx. 20m/h, this is designed to reduce the impact speed, not necessarily to stop you from having an accident.

Above that speed it gives you a visual and audible warning (and applying the brakes slightly so the pads are on the discs), if the driver does not do anything this is followed by applying the brakes in such a way that you wouldn't crash (if possible), if an accident is imminent it will slam the brakes on to reduce impact speed.

[andrewparker]

My understanding was the City Braking was active under 18mph, and therefore a low speed collision like that shouldn't happen, but can if there simply isn't enough time to avoid it.

[fredgroves]

You tboned another car?

If the other car was crossing at 90 degrees in front of you,  it was moving and you were doing 10mph then I doubt that the system had time to spot the danger and react. By the sounds of things, whatever happened, it happened in a split second and at close distance to the final impact point.

[Mark V GTD]

Agree with Fred - CEB will only stop you if you are approaching another vehicle that is directly in front of your car (either moving or static) or a fixed object directly in front - and only up to the threshold speed as noted above. The object has to be continuously in the line of sight of the sensor in order for it to deduce the object as a threat and brake warn/brake accordingly. An object moving from the side in to the radar field of view will reduce the time the system has to process it and cannot be relied upon to prevent a collision.

[fredgroves]

I'm sure future improvements will be able to deal with this, but probably not until the networked car comes out (and the thing you try to drive into is also networked )

The networked car of course is a requirement for fully autonomous driving modes anyway, so it won't be your fault if it crashes... you'll get a blue screen of death to upload to your insurance company

[monkeyhanger]

I don't think the systems work at all on static objects.

Above 18mph, DCC relies on the radar sensor to detect a moving object in front of you that slows down in front of you, and prompts you to brake or does so.

Below 18mph (city emergency braking), the parking sensors take over radar sensor duties to determine the need to brake.

Something driving across your path very close will not prompt either system to jump in and assist.

[fredgroves]

Definitely ACC radar doesn't detect static objects - that is listed in the manual. It also has upper limits on closing speeds (not listed in the manual!).

As you say, CEB is done with the parking sensors and is really for low speed rear end accidents at junctions and in lines of traffic.

Try (perhaps not!) driving into your drive and see if the parking sensors kick in before you hit something (like your garage door!).

The ultrasonic parking sensors have some serious lag on them, they just aren't about rapid reactions!

[Mark V GTD]

I was under the impression that up to 18mph the CEB system will stop you if you approach a static object. I seem to remember the Fifth Gear test which used an Up! but may recollection may be wrong - I think its on Youtube - I remember it because the very expensive Mercedes system using radar and ultrasonics failed!

[p3asa]

The VW advert to highlight the system working was 2 thieves trying to smash their way through a static road barrier in a Golf and couldn't do it.

https://www.youtube.com/watch?v=HA0A6qh5rso