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Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Wednesday 29th August 2012 quote quote all
How would i go about working out if i can stop within the distance i can see? could i chuck something out the window and slam on the brakes at the same time, then go back to the point where the dropped object landed and see if i can see the point at which the car came to a rest?
But in all seriousness, how can i figure whether im cornering too hard? Part of me is adamant i could slow the car down if i cam across a walker mid corner, yet another part wonders whether i would be able to.
Sorry if my post makes no sense, if it doesnt, just ignore it smile

Nigel_O

367 posts

99 months

[news] 
Wednesday 29th August 2012 quote quote all
lobbing something out of the window won't work, as it will be travelling at the same speed as you are, so it won't stay at the place you threw it out....

The problem is that stopping distances are variable. Road surface, tyres condition, weather, driver alertness - all have a part to play.

When the mood takes me to follow the rule of "always be able to stop in the distance you can see to be clear" I generally go over the top and give myself at least an extra 50% - this often means I can drive along in traffic without having to brake, whereas all the cars in front are braking every few hundred yards.

My suggestion would be to find a (deserted) stretch of road, then do some brake tests, using road markings or lampposts as markers. Work out the distance it takes you to stop from (say) 40mph and 60mph.

Right - now you have the distance it will take you to stop - you need to convert it to a number of seconds. Go back over the same stretch of road and time how long it takes you to cover the distance it took you to stop.

Next, add at least one second, preferably two, for reaction time. You now have the MINIMUM timespan you need between you and the car in front, or the limit of your clear vision.

I also suggest you repeat the exercise in the wet - even with ABS, you'd be surprised how much more it adds to your braking distances.


Edited by Nigel_O on Saturday 1st September 15:05

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Wednesday 29th August 2012 quote quote all
I was thinking more cornering on tight narrow B roads with high hedgerows. Im more than sure that my stopping distances are great on the straights.

JPJPJP

2,512 posts

48 months

[news] 
Wednesday 29th August 2012 quote quote all
Have you heard the phrase limit point?

Bristol IAM website describes it well enough

http://www.iam-bristol.org.uk/index.php?option=com...

Practice that, its a good start

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Wednesday 29th August 2012 quote quote all
JPJPJP said:
Have you heard the phrase limit point?

Bristol IAM website describes it well enough

http://www.iam-bristol.org.uk/index.php?option=com...

Practice that, its a good start
Limit point doesnt help you access whether you can stop. it only lets you know whether the bend tightens or opens.
Its possible that the limit point could be going away from you, so you accelerate, yet if you are already going too fast to stop in what you see then thats no good.
Limit point only helps you adjust your speed to the ferocity of the bend.
Or have i missed something?
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andy_s

9,519 posts

139 months

[news] 
Wednesday 29th August 2012 quote quote all
No, although the limit point on the high hedged roads described would probably also be the extent of vision.

S. Gonzales Esq.

1,865 posts

92 months

[news] 
Wednesday 29th August 2012 quote quote all
Worth remembering that it's all too easy to think of the Limit Point as the point where the nearside verge meets the offside kerb. In fact, it's the furthest point you can see along the nearside kerb. If there's a group of pedestrians standing there and a truck coming the other way, then that's where you need to be able to stop.

Find a quiet bit of road and practice some emergency stops, working up to reasonable road speeds and full ABS activation. Then do this on a gentle bend and feel the difference. Next, leave a cone or similar at the kerb and drive round the bend at your usual speed, stopping when you see the cone. Be honest with yourself, and then add a bit of margin for error. Then, come back and tell us how you got on.

If your newly lowered speed into bends makes you feel like you're not making progress, compensate by really concentrating on chasing the Limit Point when the bend opens up.

1point7bar

1,091 posts

28 months

[news] 
Thursday 30th August 2012 quote quote all
If you brake hard with a large sidewards G loading on the chassis, you will probably lose control.

7db

5,862 posts

110 months

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Thursday 30th August 2012 quote quote all
That's all good learning, too, although better done on an airfield than a road. Go and play with Don Palmer for a day if you really want to understand it.

Remember - if you've £10 of grip and spend £5 on cornering, there's only £8.67 left for braking.


Tartan Pixie

672 posts

27 months

[news] 
Thursday 30th August 2012 quote quote all
Possible suggestion, get a tape measure and chalk a few lines on the road at 50 cm intervals.

Use a video camera to record the footage, preferably tripod mounted or at least held very still.

Try not to kill the cameraman.

Might be quite fun to do, I'm sure you'd learn something anyway from watching the footage back.

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Thursday 30th August 2012 quote quote all
S. Gonzales Esq. said:
Worth remembering that it's all too easy to think of the Limit Point as the point where the nearside verge meets the offside kerb. In fact, it's the furthest point you can see along the nearside kerb. If there's a group of pedestrians standing there and a truck coming the other way, then that's where you need to be able to stop.

Find a quiet bit of road and practice some emergency stops, working up to reasonable road speeds and full ABS activation. Then do this on a gentle bend and feel the difference. Next, leave a cone or similar at the kerb and drive round the bend at your usual speed, stopping when you see the cone. Be honest with yourself, and then add a bit of margin for error. Then, come back and tell us how you got on.

If your newly lowered speed into bends makes you feel like you're not making progress, compensate by really concentrating on chasing the Limit Point when the bend opens up.
Leaving a cone mid bend on a NSL road could be asking for trouble, as i dont own a private airfield.

The speed that the average driver corners at, is it low enough to be able to stop? Sometimes i do wonder. Most of the bend around my area of Dorset have ridiculously closed views.

I also worry about practicing emergency stops on a corner on a public road, "sorry i crashed, officer, i was just practicing to ensure i could avoid a crash if the time arose!" biggrin

S. Gonzales Esq.

1,865 posts

92 months

[news] 
Thursday 30th August 2012 quote quote all
Benbay001 said:
Leaving a cone mid bend on a NSL road could be asking for trouble, as i dont own a private airfield.
I didn't say that. I said leave a cone on the kerb, but you could just as easily tie a carrier bag to a bush or chalk a line on the road.

Benbay001 said:
I also worry about practicing emergency stops on a corner on a public road, "sorry i crashed, officer, i was just practicing to ensure i could avoid a crash if the time arose!" biggrin
You missed the bit about working up to a full stop then. Probably better to do it on an open bit of road too, but as you seem to be a bit short on common sense it might be best just to drive slower.

If you're convinced that performing a firm stop would lead to a crash and an encounter with the law, you'd best avoid it. thumbup

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Thursday 30th August 2012 quote quote all
S. Gonzales Esq. said:
You missed the bit about working up to a full stop then. Probably better to do it on an open bit of road too, but as you seem to be a bit short on common sense it might be best just to drive slower.

If you're convinced that performing a firm stop would lead to a crash and an encounter with the law, you'd best avoid it. thumbup
I know full well how quickly my car stops in a straight line, but havnt got the guts to try it whilst cornering. I guess i could find a deserted car park and brake at 30mph whilst turning, and then, assuming it remains neat and tidy, i could try it on the road, at a higher speed.

JPJPJP

2,512 posts

48 months

[news] 
Thursday 30th August 2012 quote quote all
'Advanced Driving people have a condescending attitude' says Joe Public who has a genuine question about improving his driving

No they don't chorus some advanced drivers

Read this thread to just before this point... "but as you seem to be a bit short on common sense it might be best just to drive slower."

OK, some of them do

And another road user is maybe steered away from advanced driving

OP, seriously for a moment this is about practice and your own judgement of being safe on the road. If you can find a local advanced driving group (IAM or ROSPA / ROADAR), I would encourage you to have at least one session with one of their observers specifically on this topic.

The limit point is a good thing to think about but, if you feel that you are going so fast that you can't safely stop on your side of the road in the distance that you can see to be clear, slow down. Unless you do actually do the 'experiments' to test the validity of the limit point, it will only ever be a theory to you.

Also, if you aren't used to doing full on 'emergency' stops then if you ever need to (and you likely would the first time a woman pushing a pram appeared at the limit point on an NSL road), it would be alien to you and might not be the most enjoyable thing you have ever done. It does no harm, therefore, to knock a couple of mph off on twisties to build in a bit more of a safety buffer.

S. Gonzales Esq.

1,865 posts

92 months

[news] 
Thursday 30th August 2012 quote quote all
JPJPJP said:
OK, some of them do
No no no - that was sarcasm, not condescension. Not always easy to tell the difference, but keep practicing and I'm sure you'll get the hang of it. wink

I'm sure you know the feeling when someone asks a question and then responds to a reply in a way that seems to ignore half the points and then deliberately misunderstand the rest. This may have triggered my mild rebuke, but the OP doesn't seem to have taken offence so where's the problem?

Back on topic, I also worry that until the OP has done some practice, it might compromise their response in an emergency situation. Better to find a way to work on it that they're comfortable with (20mph on a gentle curve?), or seek outside help as suggested.

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Thursday 30th August 2012 quote quote all
JPJPJP said:
OP, seriously for a moment this is about practice and your own judgement of being safe on the road. If you can find a local advanced driving group (IAM or ROSPA / ROADAR), I would encourage you to have at least one session with one of their observers specifically on this topic.
Ive passed. But did you mean, get extra observed drives purely on this subject?
When on a hoon (gee, i hate that word, but no substitute came to my head) I tend to slow down to "normal" cornering speeds and accelerate hard as soon as the road opens out, but even with such a drastic speed reduction, im still not sure whether id be able to stop in time, maybe im just over thinking things.

Im getting to that stage where i wish i hadnt posted this topic. frown

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Thursday 30th August 2012 quote quote all
S. Gonzales Esq. said:
I'm sure you know the feeling when someone asks a question and then responds to a reply in a way that seems to ignore half the points and then deliberately misunderstand the rest.
S. Gonzales Esq. said:
leave a cone or similar at the kerb and drive round the bend at your usual speed, stopping when you see the cone.
How am i wrong to assume that you meant leave the cone on the road? If there is a curb on the stretch of road i am using then im going to see the cone long before i would if it was a tight bend with hedgerows.


JPJPJP

2,512 posts

48 months

[news] 
Thursday 30th August 2012 quote quote all
The only real way you will know is to practice it

But it wouldn't hurt to have someone who knows their stuff to sit as an observer - the ride drive guys are usually quite good

Centurion07

3,106 posts

127 months

[news] 
Thursday 30th August 2012 quote quote all
Am I the only one that thinks the OP is going too fast then?

If you don't KNOW you could stop in time, you're going too fast.

Benbay001

Original Poster:

3,229 posts

37 months

[news] 
Thursday 30th August 2012 quote quote all
Jesus fking Christ i never wanted a witch hunt!!

I give up, if anyone has anything interesting or relevant to the subject topost then post it, and i will consider replying.
Otherwise grow up, and try not to judge someones driving ability when you have never even met them, yet alone observed their driving!
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