Hoppy

You know that ad that shows some poor kid being mown down by a car with locked wheels, which goes on to say that it takes 21 feet longer to stop from 35mph than it does from 30?

Sounded ridiculous to me, so I thought I'd do a few trial stops to compare. Okay, I've good good brakes, ABS, good tyres etc. But what do you think the difference was between 35 and 30mph in my car? 15 feet? Would be a big improvement. What about ten feet - less than half the quoted difference? Nope.

In my case, the difference was six feet. And I did three stops at each speed, all within about 18 inches of eachother, so I can't be far out.

I am not dismissing the carnage of hitting anyone at 20mph, let alone 35mph, but stupid propoganda like that ad only serves to undermine the safety message.

Richard.

N1 SPAN

excellent trial, guess someone needs to do it, by the way, reckon someone needs to point out to the Nissan Sunny driver on the ad that it may help if he decided to engage the rear brakes. Could possibly shave a foot or two of the stoppping distance.

elgordano

And why don't they pick on the pedestrian !!
What the hell was he doing in the middle of the raod anyway !!
G.

FreeT

Did you not see the gorgeous bird in the hairdressers as he passed by, obviously he was distracted.

Does it matter, you don't need a license to cross the street.

And your not going to kill a car if you run into it.

Tiggs

hoppy, i assume your ready for all off your braking? i would expect that 21 feet allows for reaction time as well as foot on the brake?

MattN

I heard a rumor car manufacturers wanted to use this advert to make people buy newer cars with better brakes etc.

Also, to say that every car in the world takes 21 feet further to stop is just stupid.

It should say, some cars may possibly take 21 feet further to stop.

Mash

Also the rear wheels are NOT locked but the fronts are well and truly smoking!!! major flaw in the advert if you ask me, as assuming the rear brakes do actualy work, they usualy lock easier than the fronts due to wait transfer on braking. Are the advert's figures based on a car with no rear brakes......

juan

anyone who locks up in a normal car will find the fronts lock not the rears
Plenty of cars do not have abs. The abs will seriously reduce your stopping distance, espescially in the wet.

Ever thought that it would be wise of them to quote the difference in a worst case scenario tp prepare and proper inform people??? So I expect when its wet and you're driving an older less able car it could well be 21 feet.

or maybe they should just have a massive list of the distance it takes every model of car in a variety of weather conditions?

[Edited by juan - 2/18/2002 9:18:16 AM]

Tiggs

maybe they should do like sky news have a "push your red button now if your a subaru enthusiast and would rather we spoke to you about the effect your 9 pot braking system and rally like skills will have on your stopping"

P1Fanatic

I think tiggs hit the nail on the head with the reaction time. Under ideal conditions most people could stop their car safely and quickly. Like in your driving tests emergency stop - you know its coming as youve been told. However the real world isnt like that - it will be sods law that kid/animal/vehicle etc jumps out in front of you when u least expect it e.g when picking ur nose/ answering your mobile/changing cd/scratching ***** (Delete as appropriate).

SWRTWannabe

They have probably come up with 21 feet as it is 6 feet extra stopping distance, and 15 feet "thinking distance".

Good point though, what was the bl00dy pedestrian doing in the road though - maybe needs a refresher on the green cross code

tiggers

I've always wondered about that ad, but couldn't ever be bothered to do a test myself so fair play to you Hoppy. While I understand what some of you are saying about less able cars, non-ABS etc. I do still think the ad is misleading.

Anyway when I was a kid they used to run ads about how to cross the road (remember the Green Cross Code), why don't they run these anymore? Oh Yeah, I forgot that kids these days can do no wrong hence if you hit them when they run across the road in front of you it's always your fault!!!! If parents spent a little more time disciplining their brats instead of letting them behave how they want and then backing them up no matter what they do Britain would be a better place to live. As it is it sucks!

Regards,

tiggers

Scooby370beast

Well,Stupid people should stay of the road.Anyway this ad should advertise scoobs are the safest cars because stupid people listen the rumble coming down and anyway they would move from the middle of the road ha!Unless they are deaf,but if they are deaf they should look b4 crossing.Stupid advertisements

CraigH

Doesn't the ad say, it takes "this" car - ie the Sunny.

I think they just found the 5hittest braking newish car they could.

New cars wouldn't take that long.

Agreed about the reaction time though.

Elvis Presley

Am I mistaken, or does the advert say it takes an EXTRA 21ft?

Why are you suggesting that it takes an extra 15ft in reaction time?

Does driving faster slow your reactions?

Does this mean that at 30mph you have lightening reactions?

stephen30

One thing I seem to remeber when I was learning tio drive was my instructor telling me that if I lock the wheels, ease off the brakes a bit then reapply, as abs does automatically.
Pity they didn't think of that on the Ad. Also, did anyong notice the guy streering round the obstacle? If a kid ran out on front of me that's the 1st thing I'd do!

Steve

scoobs

No Elvis, If your Reaction Time was say 1/2 sec then when travelling 35mph you would travel an EXTRA 15feet within that time.

Your reactions are the same, but the distance you travel within that period increase as the speed goes up.

Scoobs

TRIGGER

your maths are surely incorrect - in half a second you travel about 25 ft at 35 mph as against 22 ft at 30 mph - so we are looking at 5 sec reaction times are we ?

juan

stephen - if you're locked up you can't change direction. Many people will panic and stamp on brakes to stop. During this panic many won't think about pumping the brakes to simulate neanderthal abs and thus have a bit of steering to play with, and plenty won't even know this is possible.
Also, whilst I uinderstand what you're saying about the pump the brakes etc. they're actually trying to get you to slow down, not trying to get you to keep speeding but just be aware of ways to possible brake better

Elvis - if you're travelling faster you're going to cover more distance even if your reaction time is exactly the same. Pretty simple.

Most people don't own high performance cars. plenty of basic cars do not have abs. most cars will take more distance to stop than a subaru. Distance will easily double, and usually more if the road is wet. FFS 21ft extra seems reasonable if you're in a basic car and its wet.

To pre-empt more moaning I know its not raining in the advert but they're trying to make you aware that the extra speed CAN make a big difference to your stopping distance in various circumstances.

Just because Joe Schmoe in his supercar can stop with just an extra 6ft in ideal circumstances doesn't mean this applies in all situations to all cars.

man we need a teacher on these boards.


can anyone remember the stats of children surviving after being hit by cars at 30mph and 40mph. Can't remember exact figures but something like 17 or 19 out of 20 hit at 40mph die and much much less at 30mph. Makes you think. Well at least you would hope it would.

Also, has anyone ever seen these tests they do sometimes on topgear and the like showing the difference between abs and non-abs - BIG difference. The guy in the ad doesn't have abs. Nuff said

[Edited by juan - 2/18/2002 12:18:03 PM]

carl

The guidelines on braking in the highway code show thinking distance (ft) = speed (mph). So the difference in thinking distance between 30 mph and 35 mph should be 5 feet.

juan

Hoppy, next time its raining go and borrow someones crappy base model Fiesta, ideally with not much tread left on the tyres, and try the same test and post your results

if the extra reaction distance is 5ft then your extra stopping distance being 1ft is very impressive

[Edited by juan - 2/18/2002 12:14:49 PM]

SWRTWannabe

Oops, I was getting my yards and feet confused. Yeah, the extra thinking distance is 5 feet, not 5 yards (15 feet)

I'll get me coat

juan

d'oh. pesky corners and my poor eyesight

[Edited by juan - 2/18/2002 12:13:54 PM]

stephen30

Regardless of whether the science is right ot not, it's just the Govt trying scare us all into driving more slowly. In a similar street I think I'd be driving quite carefully. There seem to be cars on both sides of the road etc ie: Lots of hazards and not easy to see people walking out into the road.
We've all just got to be sensible out there!

Steve

juan

I think its the govt trying to get us not to break the speed limit in built up areas if you pay attention and showing us what a difference even 5mph makes. They're not saying drive at 20. They're saying look at the difference between 30 and 35.
Like you say its a risky scene - cars on both sides etc. Plenty would drive at 30mph and no more but some will hare along at 40 or 50. Mind you these are the ones who will ignore this type of ad. so it could be a bit pointless from that point of view

[Edited by juan - 2/18/2002 12:22:36 PM]

FreeT

Would it not help if they just introduced more pedestrian crossings as well and a 25mph limit in built up areas so that even if you are mad enough to spedd and extra 5mph it will still only be 30.

simes

Braking distances in highway code are calculated as

speed + speed squared/20

i.e 75 feet at 30 mph and 96.25 at 35mph hence the 21 feet.

However, this calculation has remained the same for at least 25 years that I know of, so improvements in brakes and tyres have not been taken into consideration.

However, if you're driving around in a Morris Minor, be careful

Cheers

Simon

[Edited by simes - 2/18/2002 1:36:13 PM]

igratton

Richard,

this is a very interesting thread. I (and the most of us) couldnt live with having run down a ped. or cyclist.

I've always wondered how the Highway code folks calculated stopping distances. I always wondered if they were still based upon a Morris Minor and its braking ability (like our motorway speed limits LOL ). I guess there are (at least) the following variables.

Driver Reaction Time
Weight of vehicle (Mass)
Speed
The ability of the brake components fitted to the car etc.

I will keep reading...its one of the best threads in ages

Ian.

juan

well researched Simes,

so anyone miffed with the ad should now blame the highway code. Of course we should all have known the stopping distances seeing as we've all passed our tests!!

tiggers

Ok as we're getting into discussing differences between different types of vehicle, road surfaces, speeds etc. can I introduce one more factor. Many vehicle manufacturers spend millions on designing crumple zones to protect both the occupants of the vehicle in an accident and pedestrians that may be hit by the vehicle in an accident.

Why oh why does the law then allow the moronic majority of 4x4 (and by that I mean Land Rovers, Shoguns, Suzukis etc. not Scoobies) owners to bolt bull bars to their vehicles. I mean who the f**k needs bull bars when going to Sainsburys (which is all most of these idiots ever do with their tractors).

I'm sure a kid getting hit by one of these things at 30mph is far more likely to die than if they are hit at 35mph by a properly designed car.

Do these people think about that when they purchase their ridiculous fashion statement, probably not, but then most of them haven't got a brain or they'd buy a proper car instead.

Regards,

tiggers.