So I went on a Speed Awareness Course last night, that's 4 hours of my life I'll never get back.
The guys giving the talk was your usual IAM instructor who clearly NEVER broke the speed limit for any reason. Anyway, he told us that stopping
distances have not changed since the 1960's. He reckoned that ABS does not decrease your stopping distance at all, just allows you to manouver
when you're breaking. And with cars heavier now than they used to be the better breaks we have just end up doing to same job.
I disagreed with him completely, saying than the combination of ABS, better brakes and better tyres must make a difference. He's trying to say
that a 1970's Granada would have the same stopping distance as a modern BMW.
Your thoughts?
The other interesting thing was that they talked about collisions a lot. I asked the other instructor what percentage of collissions were caused by
excessive speed. She could'nt/wouldn't give me a decent answer, and only said that a small amount. So why the hell did I have to listen to
an hour talk about collissions when I was done for speeding - not dangerous driving?
There was a guy there who had been done for speeding rushing his bleeding wife to the hospital. They then went on to try to tell him he should have
kept within the speed limit even in this situation - that he would have got there just as quickly. One bright spark then asked why ambualnces bother
to drive fast with flashing lights if it makes no difference? They stuck to their line - there is NEVER a good reason to break the limit. If it was my
wife bleeding I know what I would do - and in fact my father-in-law is only alive now because his wife drove a top speed to the hostpital when he had
an anaphylactic reaction to a wasp sting - the hospital staff told her he only lived becasue she did.
Anyway, I could rant on and on, as you can imagine they did really like it when I kept tell them that the police should target bad driving - not just
nick people for speeding in completely safe situations just as a revenue earner.
If you're not living life on the edge you're taking up too much room.
I think the combination of ABS, Tyres and better brakes have improved things dramatically.
I have also been on a course similar to the one you have been on I think the IAM man was towing the line, The IAM teach you to break the speed limit
in certain circumstances especially when it gets you out of trouble.
The courses are a bit of a joke though and as you say they never seem to have the facts and figures to hand to prove what they say.
I was most amused to watch those who had been on the course with me scream out the car park and race off down the road afterwards!!
I was there for doing 33mph in a 30 zone, there was one woman who had got done for 31 in a 30 zone, the policeman there blamed the cameras as faulty -
but that didn't help us, the cost of the course was £120.00- either that or three points.
What a total waist of time.
Duratec Engine is fitted, MS2 Extra V3 is assembled and tested, engine running, car now built. IVA passed 26/02/2016
I did a small research project on ABS, and with regarding to stopping distances in a straight line I came to the conclusion that it depends on the
driver. If the driver knows what hes doing and is pumping the brake pedal rather then pushing it harder then no ABS probably doesnt decrease them.
However to the normal driver that just pushes the brake harder when they start skidding, then yes ABS is an advantage..........
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I personally find ABS increases stopping distance slightly in some situations (snow, gravel) but in most conditions it's pretty much the same as
"good" braking technique. But overall tyres and brakes are a hundred times better than 40 years ago. Clearly your instructor was
attempting to make a point to slow people down, shame telling porkies doesn't work with people who know more than you. I have found that most
IAM members are sanctimonious know-it-alls who like to force their own (sometimes incorrect) opinions on you at every chance. Giving them the role as
instructor in such a course is bound to make that worse.
I too did some research in my car with ABS in the snow. I found that I could stop in the shortest distance with good control and careful cadence
braking and careful steering inputs, followed ABS at about 1 car length further without steering inputs with the ABS keeping the car straight, then
finally without ABS and without steering I ended up sideways and about 3 car lengths further I drive with the ABS fuse pulled in thick snow.
On certain sufaces like gravel, snow and ice ABS can make the braking distance longer, BUT, you can remain in control. ABS afterall is just another
"driver aid" and helps maintain control rather than just simply shortening stopping distance.
Although i totally agree with the OP, the course I went on was full of flaws, and when questioned no reasonable explanation could be given. It was
like, were right your wrong, and even if you can prove a valid argument, were still right and your in the wrong.
Again when I questioned one part, I was simply told, If you were right you wouldn't be here..... TOSSSERS
Stopping distances in the highway code have been a joke for years. Everyones best friend, Jeremy Clarkson did a Topgear short on it. You can watch
it, but his old 1997 Lexus stops at 70mph in 139ft, versus the 246ft in the highway code. Old Lexi (cheers Mr Partridge) are pretty heavy, right?
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posted on 10/11/11 at 11:08 AM
I think it will depend mostly on the driver, the basic physics of friction has not changed, you need the wheels to be turning just under skidding
(locking up) to get the maxim braking... But ABS can react much faster than a human, so there might be some advantage, but this is probably small.
Stopping distances though have probably decreased for mr/mrs average though as they don't apply enough pedal pressure in an emergency but with
high servo ratios and ABS of modern cars this is not a problem as light pressure is all that is needed; hence modern cars with brakes with no
"feel" to them..
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posted on 10/11/11 at 11:10 AM
quote:Originally posted by deezee
Stopping distances in the highway code have been a joke for years. Everyones best friend, Jeremy Clarkson did a Topgear short on it. You can watch
it, but his old 1997 Lexus stops at 70mph in 139ft, versus the 246ft in the highway code. Old Lexi (cheers Mr Partridge) are pretty heavy, right?
Weight has nothing to do with it (if the correct tires are being used that is, i.e correct load rating and brakes sized properly), the coefficient of
friction remains the same irrespective of weight.. Buses stop very well, and weigh 10's times more than a car..
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posted on 10/11/11 at 11:12 AM
quote:Originally posted by big-vee-twin
I think the combination of ABS, Tyres and better brakes have improved things dramatically.
I'd go as far as saying that the tyres probably make the biggest difference, especial if we're talking about half decent rubber and not
£20 per corner rubbish
didn't those togear idots do some kind of tests over the years to see how modern cars performed against the stopping distance in the code....
from my own experience I started out in a 1979 mk1 fiesta (730kg, 145/82 R12 first the michelin ZX's then modern budget tyres)
then 'upgraded' to a 1992 s1 pug 106 (760kg, 145/70 R13 also with michelin ZX's, then budget tyres of the same type)
so thats about as close a comparison as I can think of between 70's design and 90's design
obviously neither had ABS, both of them had rubbish stopping distances, but there was a big difference changing to the more modern tyres and even
after that the 106 felt like it stopped quicker and safer (although I never got the chance to measure that really...)
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posted on 10/11/11 at 11:13 AM
Technically a car with ABS and the same vehicle without have the same stopping distance... when the driver is perfect enough to control the braking at
the max without locking wheels. There are very few of us capable of that.
An less skilled/normal driver just applying max pedal effort (ie causing the ABS to opperate) against the "perfect driver" in the non-ABS
car will take further to stop. The ABS releases the brake afterall, but it thinks far faster than us so it's very marginal. The normal driver
trying to stop the non-ABS car will take even further to stiop due to either skidding or not applying max braking force.
ABS is designed to allow you to steer when emergency braking (even our imaginary perfect driver above can't do that). In most cases you only
need to do that if you're driving within your stopping distance.
Yes, a modern cars stopping distance has decreased. What increases in technology haven't done is reduce to thinking/reaction time and that is a
bigger factor than the actual breaking distance.
ABS cant change physics, given the same tyres and weight the theoretical stopping distance cannot change, it just lets drivers who panic and mash the
pedal into the floor come close to that physical minimum whilst steering. That said, i challenge even a good driver to beat it (and there arent as
many good drivers as people who think they are;-) )
Modern tyres have massively reduced stopping distances.
Modern brakes havent really, they tyres always have been and still are the limit. If you can lock your wheels, your brakes are better than your
tyres.
Speed awareness courses are a good way of making money. First you get done for speeding and should have the right to a fair trial. Then they bully you
into 3 points and a £60 fine if you go quietly and dont question it, then they offer to drop the points if you pay them another £60. Its a shocking
indication of the way this country is going.
Why is that important?
When your brakes lock up on wet and slippery roads or during a panic stop, you lose steering control and your vehicle can spin. Rear wheel ABS
prevents wheel lockup so that your car stays in a straight line. If your car has ABS control on all four wheels, you also keep steering control. If
you have steering control, it is possible to avoid a crash by steering around hazards if a complete stop cannot be accomplished in time.
Most cars in 1960 were fitted with drum brakes on the rear and in most cases wouls cause most cars of the era to nose dive. but I suppose were a lot
lighter.
Personally I cant se the stopping distances being the same. one pratting arround in my A6 ABS and Brake assist .
did a simulated emergency stop and avoid ( no cars about ) on A59 from the national speed limit to 0 on a crud peice of tarmac stopped on a
sixpence it even fired the hazards on to warn other vehicles.
regard
Agriv8
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tree full of a*seholes .............
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posted on 10/11/11 at 11:21 AM
Just checked a 1990 South African "Car Magazine" comparative road test of a 1990 VW Golf GTS and Mazda 323 and stopping time from 100kph
was an average of 3.6 secs with a best of 3.4 for both - modern Golfs stop in around 2.9 secs or thereabouts - a huge difference, so he doesn't
know what he is talking about.
In fact modern hatchbacks are now commonly achieving stopping times that where the preserve of supercars pre 1990s
ps - for those who don't know - South Africa's Car Magazine's tests have always been at the cutting edge of car testing using the
most modern measurement systems available at the time.
quote:Originally posted by alistairolsen
ABS cant change physics
Awww man! Seriously? Well there goes my faster than light space ship, based on physics bending ABS technology..... might as well bin the whole
project now
The woman done for 31 could have chosen to go to court were i suspect she would have won.
quote:Originally posted by big-vee-twin
I think the combination of ABS, Tyres and better brakes have improved things dramatically.
I have also been on a course similar to the one you have been on I think the IAM man was towing the line, The IAM teach you to break the speed limit
in certain circumstances especially when it gets you out of trouble.
The courses are a bit of a joke though and as you say they never seem to have the facts and figures to hand to prove what they say.
I was most amused to watch those who had been on the course with me scream out the car park and race off down the road afterwards!!
I was there for doing 33mph in a 30 zone, there was one woman who had got done for 31 in a 30 zone, the policeman there blamed the cameras as faulty -
but that didn't help us, the cost of the course was £120.00- either that or three points.
What a total waist of time.
Life moves pretty fast, if you don't stop and look around once in a while, you could miss it.
ABS increases stopping distances by a very skilled driver by a very small margin when compared with those that can be achieved --- but ABS
allows a maximum G stop under control. The more modern ABS systems are considerably better than the early systems as the wheel sensor on the most
recent systems are more sensitive and the resultant control of the break pressure by the ABS ECU is less coarse, this is why modern ABS system are
better than the older generation systems in ice and snow.
Modern cars can stop in a slightly shorter distance than 1970s cars mainly due to having more rubber on the road, the big improvement in braking
performance came in the 1960s when front disc brakes started to be fitted to entry level cars.
Not so much because of brake fade issues as the main problems with front drum brakes fore everyday motoring was they were prone to snatching at slow
speed, pulling to one side, suffered from leaking wheel cylinders and always needed regular adjustment. front drum brakes also gave a very
non-linear pedal response because the brake shoes and drums distort under the force exerted by the wheel cylinder.
When entry level cars like the Anglia, Escort, Viva and Marina had drums on the front come MOT time they would more often than not fail on brakes
pulling to one side for no obvious reason. A trick we worked out was to swap over the brake drums left to right often that would fix it.
Even the most skilled driver in the world can not control every wheel individually. If one wheel locks up he has to judge whether it will be
advantageous to release pedal pressure and regain traction on the wheel (losing braking effort from all the other wheels in the process) or whether to
just leave it locked. A good ABS system will release pressure only on that wheel so no braking effort is lost on the others.
quote:Originally posted by big-vee-twin
I was there for doing 33mph in a 30 zone, there was one woman who had got done for 31 in a 30 zone,
I've heard this claimed a few times but no one has ever produced a speeding ticket with 31mph on it (in a 30mph limit); I just don't think
it would happen.
My 1964 Morris Traveller will happilly lock all 4 wheels from 30/40/50/60 ... drums all round, 155 R 14 tyres ... does squirm a bit, and I
wouldn't like to do it more than once! It's probably under the 'stopping distance' quoted too!
I can't understand people bleating on about the Driver Awareness thing.
Before it came along you would get a fine, 3 points, a hike in your insurance premium and no choice.
At least now you have a chance to keep the points off for when the renewal comes round.
The course is just an alternative punishment, like making you sit in the corner or on the bottom step with maybe the odd person picking up something
they didn't know. It would be cheaper for the government just to make you pay the fine rather than have centres and instructors all over the
country.
As Normal Stanley Fletcher said "Can't do the time then don't do the crime"
ABS has saved my life more than once both in stopping power and being able to steer whilst braking. Doesn't matter how good a driver you are,
when the unexpected leaps out at you very few people will be as quick and efficient as an electrical circuit.
But as stated above the tyres are the limiting factor in the end and cars being heavier put more demand on them for stopping adhesion. My MK2
Scirrocco only has a book weight of around 900kg. Compare that with the new Mk3.
Speed doesn't cause accidents, drivers do. Speed just makes the results potentially more significant as I=MV²
I drive with the ABS fuse pulled in thick snow. 
to 0 on a crud peice of tarmac stopped on a
sixpence it even fired the hazards on to warn other vehicles. 
