# Advert:35mph stopping distance



## KevinST (May 6, 2002)

The one where a child is knocked down because the driver was doing 35mph and couldn't stop in time...

... well if the bloody rear brakes worked then the car may have stopped quicker !!!!!

Watch the advert - the fronts have locked (idiot driver can't brake properly - release them !!! ) and the rears are still spinning.

Don't get me wrong - we all know that it takes longer to stop the faster you're going, and that irisponsible speed can kill, but if you're going to "educate" people about this then get the stunts right!!

Oh - and while I'm on the subject, what happened to the green cross code?? why was that child running out infront of traffic anyway ??


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## coupe-sport (May 7, 2002)

> Don't get me wrong - we all know that it takes longer to stop the faster you're going, and that irisponsible speed can kill, but if you're going to "educate" people about this then get the stunts right!!


Its showing how an average driver would react - its supposed to make you think. Who cares if the dynamics are slightly wrong.



> Oh - and while I'm on the subject, what happened to the green cross code?? why was that child running out infront of traffic anyway ??


Kids don't think like adults and sometimes do impulsive things like run out in front of traffic


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## Dubcat (Jun 10, 2002)

That advert made me think. It made me think about driving within the speed limit in 30mph areas. I don't know how I would live with myself if I did that to someones child/sister/father/etc. 
W.


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## phil (May 7, 2002)

> That advert made me think. It made me think about driving within the speed limit in 30mph areas. I don't know how I would live with myself if I did that to someones child/sister/father/etc.
> W.


Me too. I knocked somebody down a few years back. A girl pretty much the same age as me (and should have known much much better) ran out in front of me between parked cars. She was on her phone and didn't even look. Fortunately for her I was doing 15-20 mph and it was dry but she went flying although was pretty much unhurt. Her phone smashed into pieces.

It frightened the crap out of me. And quite frankly I don't know what I'd do if I ever killed somebody.


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## r1 (Oct 31, 2002)

I think it's a superb accident - not only technically but also for sheer impact.

As has been said - who gives a shit whether it's accurate or not???

The smoking ads are grossly inaccurate but somoething tells me not many people would care if they have the desired affect. Ditto this one.

:


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## vlastan (May 6, 2002)

The latest smoking ad with the fat coming out of the artery is real.

I guess a TT would have stopped in this advertisement with the child.


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## ronin (Sep 6, 2003)

> I guess a TT would have stopped in this advertisement with the child.


lets hope no one on here ever has to find out


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## KevinST (May 6, 2002)

<sigh> everyone seems tohave taken my comments wrong :-/
The flame is that they had to do the accident with a car that may not have passed an MOT (dunno if non working rear brakes is a failure or not). Not the subject of the advert, or that I disagree with the message etc etc.

I've (thankfully) never been involved in such an accident, but have witnessed more that I want to, and help out at the scene of one.

Re: the green cross code thing... I think that they were great a great education when I was a child - certainly taught me how to cross a road... why are children not educated in the same way now?? (or maybe they are and I've missed the adverts as I don't have kids :-/ ).


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## vlastan (May 6, 2002)

Kevin,

The average viewer won't notice the back wheels not locking. But you and most of us will.

The message of this ad is simple...so don't complicate it or over analyse the physics momentum of the back wheels.


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## jdn (Aug 26, 2002)

> The latest smoking ad with the fat coming out of the artery is real.


Not a real artery but an attempt to simulate the quantity of fat that can build up. But, as with the speeding ad, not a problem as it is the message and the way it is delivered that count.


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## uppTTnorth (Jul 5, 2003)

And i thought it was only me who had noticed the wheels.


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## garyc (May 7, 2002)

No me too (just replied on Off Topic) and even my wife. Â

Bald skinny tyres on front, disconnected rear brakes, no ABS. Â The car scenario could not be less accurate. Â However the point made is valid and I'd wager, none of us here would drive faster becaouse we can stop sooner in such a built up and busy area.

I am in favour of 20mph limits in such places. Â Raised after 10pm and before 6am. And zero tolerance of speeding. Â That's where the lives are really saved. Â You can only rely on kids to do reckless and impulsive things, in spite of Alvin Stardust and Green Cross Man.


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## Major Audi Parts Guru (May 7, 2002)

I've watched that advert many many times and whilst I understand the point that they are trying to make, the advert itself is very innacurate. There is no way that a car like that would lock up its front wheels for so long travelling at 35 mph :


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## vlastan (May 6, 2002)

> I've watched that advert many many times and whilst I understand the point that they are trying to make, the advert itself is very innacurate. There is no way that a car like that would lock up its front wheels for so long travelling at 35 mph Â Â :


Maybe you are right...but don't forget it is in slow motion.


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## Hannibal (Dec 1, 2003)

> You can only rely on kids to do reckless and impulsive things, in spite of Alvin Stardust and Green Cross Man.


And you can rely on drivers to speed....hence the advert. IMHO drivers speeding in built up areas is a good target (I live on the local drag strip - it doesn't bother me but I know my neighbours with kids get annoyed) but you can't ignore that some kids (and adults) have no road sense and blame the driver all the time! A bit of Green Cross Code wouldn't go amiss in my book - at least it would give a balanced view.

H


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## garyc (May 7, 2002)

> And you can rely on drivers to speed....hence the advert. Â IMHO drivers speeding in built up areas is a good target (I live on the local drag strip - it doesn't bother me but I know my neighbours with kids get annoyed) but you can't ignore that some kids (and adults) have no road sense and blame the driver all the time! Â A bit of Green Cross Code wouldn't go amiss in my book - at least it would give a balanced view.
> 
> H


What we probably need is a bunch of educational shrinks to form a working party, create a few thousand extra policy maker jobs, and assess what it is the kids _really_ need to help them assimilate the knowledge in a positive, constructive way that is non socio-economic group centric; favours all creeds and sexes uniformly; is unthreatening; and wholly politicallly correct.

I some how don't think a grown man wearing ladies green hosiery will quite fit the bill. A 5 year study needed, visiting all major countries for cross-fertilisation of concepts and approaches.

Oh and the motorist should immediately be taxed more to pay for it


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## KevinST (May 6, 2002)

> ... is unthreatening; and wholly politicallly correct.
> 
> I some how don't think a grown man wearing ladies green hosiery will quite fit the bill.


LOL ;D


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## Hannibal (Dec 1, 2003)

> What we probably need is a bunch of educational shrinks to form a working party, create a few thousand extra policy maker jobs, and assess what it is the kids _really_ Â need to help them assimilate the knowledge in a positive, constructive way that is non socio-economic group centric; favours all creeds and sexes uniformly; is unthreatening; and wholly politicallly correct.


I can't believe how naive I've been, thinking a simple message would fit the bill - bring on the working party :

H


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## Guy (May 13, 2002)

LEARN YOUR BLOODY BASICS ABOUT VEHICLE DYNAMICS AND THEN COME BACK AND COMMENT ABOUT THAT ADVERT.


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## jdn (Aug 26, 2002)

> LEARN YOUR BLOODY BASICS ABOUT VEHICLE DYNAMICS AND THEN COME BACK AND COMMENT ABOUT THAT ADVERT.


Do you mean to imply that the reason the front wheels are locked and the rears are not, is because the majority of the weight is over the front wheels, and along with a likley heavy front brake bias +/- drum brakes at the rear the rears will not lock?

That was my explanation to myself when I saw the ad. :-/


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## Guy (May 13, 2002)

Not quite, although it is true around 80% of braking is done by the front wheels and the vehicle has a brake limiting pressure valve fitted to stop the rears from locking. As does every fwd non-ABS vehicle and most commercial vehicles, from car derived vans to thundering great artics.

It is the reasons for this brake balance people should research. The brakes on the vehicle in the advert worked as they should and those who say they are defective are quite simply wrong.

To those who choose not to believe - go look it up yourself. 
If you want a practical experiment - the next time you are on ice or slippy snow reverse as fast as you can go in a straight line then applied the brakes as hard as possible. By reversing, you are putting the majority of the braking effect at the rear instead of at the front as per a normal car.
I'll leave you to guess what happens.


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## jdn (Aug 26, 2002)

> It is the reasons for this brake balance people should research. Â The brakes on the vehicle in the advert worked as they should and those who say they are defective are quite simply wrong.


This thread seems to have gone quiet now Â :-/

WHat would happen? I guess you may expect the rears to lock as they are now the 'front' wheels but the brake pressure limiting valve is still there, so maybe the fronts (which are now the rears) would lock? :-/


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## garyc (May 7, 2002)

Well I disagree.

It should be possible to lock all 4 wheels on a non ABS equipped car if they are functioning properly. Â If set up correctly the fronts should lock momentarily before the rears when full pedal pressure is applied, regardless of any dual diagonal failover plumbing or balance valves fitted . Â Balance valves are primarily for handling stability under severe braking, to balance load and not specifically to prevent rears from locking up. Â That in itself isa fucntion of ABS wheer fitted. The back end of cars with poorly adjusted brakes like the one in the Ad, will be all over the place in extremis due to cambers etc. Â That is dangerous.

It is downright dangerous having rear brakes underperforming or freewheeling (ie not working) since the main force fo retardation is dependant on the tyres contact patch - all four not just the front two.

However Guy is right in that there should be more balance of brakes towards the front because of weight transfer issues. Â The rears still have a vital role. Â If they didn't, why would anyone bother having rear discs rather than plain old cheap drum rears?

The rear wheels in that Ad are making no attempt to add to the braking effort, and forget locking up, they still show no rotational slowing at any point. Â That is not how correctly functioning brakes operate.

As a side issue, it's snowing outside now. The first quattros had the ability to turn odd ABS for some conditions. Shame you no longer have that option.

...perhaps I should reverse home.


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## Guy (May 13, 2002)

Look at the very first second(s) of that advert and you will see the rear wheel lock momentarily a couple of times before rotating to the end of the clip. That shows they are working correctly and at a maximum efficiency. 
When the rear wheels are locked that is one condition where your vehicle is unstable. If you have equal braking effort being applied front and rear how does your vehicle know which is or should be the front?
Do not forget that ad shows a vehicle under severe braking, the vehicle is skidding, it is in an emergency condition and the brake limiting valve is doing the job it was designed to do, just as Garyc says, 'primarily for handling stability under severe braking, to balance load and not specifically to prevent rears from locking up.' Think how the brake limiter valve does that. Preventing the rears from locking provides for handling stability under severe braking it does not prevent the rear brakes from working. 
ABS systems work under different rules and that vehicle does not have ABS, just as many cars on the road today donâ€™t. It is an EC rule that makes it unlawful to have an ABS that can be switched on and off - although there are exceptions)



> The rear wheels in that Ad are making no attempt to add to the braking effort, and forget locking up, they still show no rotational slowing at any point. That is not how correctly functioning brakes operate.


Tell me Garyc, how do see or tell if a wheel is braking from outside the vehicle? This is something I must learn.


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## garyc (May 7, 2002)

> Tell me Garyc, how do see or tell if a wheel is braking from outside the vehicle? Â This is something I must learn.


I was going to say 'Yes you really should Guy before expounding'. Â And, that it has to do with the visible rotational rate differences that the human eye can detect between front and rear wheels, plus the rate of rear pitch and front dive that alters with front and rear relative brake balance. Â Anyone who watches a lot of motorsport could witness that.

But then I realised that at the *beginning* of your post, you actually Â *did* know how to spot when rear brakes are working, but had obviously *forgotten *the depth of your knowledge come the *end *of your missive, when the overwhelming urge to be sarcastic overtook you:



> Look at the very first second(s) of that advert and you will see the rear wheel lock momentarily a couple of times before rotating to the end of the clip. Â That shows they are working correctly and at a maximum efficiency. Â


You walked into that one... : : :

Tell me Guy, do you by any chance have a front/back brain balance valve fitted


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## Guy (May 13, 2002)

Well Garyc, if wit were wisdom you would be very clever.

You have described a braking vehicle, now describe a braking rear wheel as you say you can. If not, go away and learn.


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## garyc (May 7, 2002)

> Well Garyc, if wit were wisdom you would be very clever.
> 
> You have described a braking vehicle, now describe a braking rear wheel as you say you can. Â If not, go away and learn.


Thanks for the compliment. ;D

Actually it was you describing a braking vehicle, majoring on the rears, and then subsequently stating that is was 'something you must learn.' Sorry to point out your contradiction. It was so blatant.

Perhaps whilst I am away learning about brakes, you might also aspire to learn to read your posts before sending, in order to avoid further any contradictory embarassment.

Or, come to think of it, any factual inaccuracies:



> It is an EC rule that makes it unlawful to have an ABS that can be switched on and off - although there are exceptions)


Care to elucidate? The only apparent reg is that ABS should be factory fitted to all vehicles over 3500Kg unladen weight.

http://www.dft.gov.uk/stellent/groups/dft_roads/documents/page/dft_roads_506817-01.hcsp

Now go away and learn them before you quote them.


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## jdn (Aug 26, 2002)

Shame. :-/ I had been following this thread with interest but it looks like it is going to degenerate into a polite row.

I find it a tricky subject to get my head round - part of me tells me that the ad is 'wrong' but also a part of me feels there may be a good reason the rears are rotating - see my earlier post.

So.. to educate me, please could Guy and GaryC post their answers to these questions:

1) Is the ad factually correct i.e. is the car behaving normally

2) If yes to Q1 - then why aren't the rears locked

3) What would happen if you were reversing on ice and you slammed on the brakes?

Thanks.


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## Guy (May 13, 2002)

Garyc. Â 
Please don't prevaricate, your post did say


> The rear wheels in that Ad are making no attempt to add to the braking effort, and forget locking up, they still show no rotational slowing at any point. Â That is not how correctly functioning brakes operate.


Could you please let us know how you can tell the rear wheels make no attempt to add to the braking effort? Â Is it because they are going round?

BTW, the exemption was put in after the EC reg was first published and will probably not be in that link. I'm sorry I don't have time to look. Â


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## Guy (May 13, 2002)

JDN


> 1) Is the ad factually correct i.e. is the car behaving normally


Two questions. 
(a) Is the ad factually correct? Without knowing the co-efficient of friction at the tyre/road interface the facts may or may not be correct. However, the distances given are within a normal range of figures.
(b) Is the car behaving normally? Yes. Perfectly normally.


> 2) If yes to Q1 - then why aren't the rears locked


Because the rear brake limiter is performing its function correctly, thus enabling vehicle stability.


> 3) What would happen if you were reversing on ice and you slammed on the brakes?


Your vehicle will rotate for one or both of two basic reasons and a few other minor ones thrown in.


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## garyc (May 7, 2002)

> Garyc. Â
> Please don't prevaricate, your post did say
> Could you please let us know how you can tell the rear wheels make no attempt to add to the braking effort? Â Is it because they are going round?
> 
> BTW, the exemption was put in after the EC reg was first published and will probably not be in that link. Â I'm sorry I don't have time to look. Â


Guy, I am going to defer to your greater knowledge on braking systems and dynamics. Â You are indeed the expert.

JDN - I do however believe the car in the ad concerned to be a *1995 Nissan Sunny*, a model that ran from 1991-1995. Â Later versions (94-95) left the Nissan line with *ABS as standard* in a marketing bid to out-specify Escorts Astras etc. So you can draw your own conclusions as to whether the brakes are operating normally, or whether they are indeed 'doctored' for dramatic effect...

http://www.ananova.com/news/story/sm_338795.html?menu=

It is anyway a highly dramatic ad. Â Discussion-provoking too, and therefore successful.


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## Guy (May 13, 2002)

> I do however believe the car in the ad concerned to be a 1995 Nissan Sunny, a model that ran from 1991-1995. Later versions (94-95) left the Nissan line with ABS as standard in a marketing bid to out-specify Escorts Astras etc. So you can draw your own conclusions as to whether the brakes are operating normally, or whether they are indeed 'doctored' for dramatic effect...


I can't confirm your choice of vehicle year or if the vehicle came with ABS fitted as standard or was an option. However, it is apparent the vehicle used in the ad was not using ABS and as such it was working in the manner a non-ABS vehicle works.
The Nissan Sunny is a model I haven't experience with but Parker's claim ABS was fitted from Jan 92 on the 2.0e GTi Sunny so it may be that it was an option on the lower spec models. '94-'95 had the 'Tropic' and 'Boston' models but ABS isn't mentioned in their spec, this could be an omission on the part of Parker's. 
The spec for the Almera ('95 to '00) shows ABS to be optional.


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