The "golden rule" of advanced driving

[Horse]

as far as I am aware the limit point is at the opposite edge of the road i.e. on a LH it is defined by the RH verge, RH bend the LH verge

I think you might consider theorising less - go out and look at a bend from a stationary point, see where the limit point lies, note what can be seen, try to work out what useful information may be gleaned, and how it might best be used while driving. If one bend isn't enough, repeat with other bends until you can draw some useful conclusions.

Park up and walk through. Gives you time to stop, look, even go back and compare.

[Carbon Based]

This was posted here some time ago, didn't get much in the way of discussion though, and it is quite a long video:

http://www.youtube.com/watch?v=qaBtGqHiEyM

[triquet]

I've done some 700,000 miles of bends. They differ. There is also a world of difference between The Bend You Know, the Bend That Is New, and the Totally Unexpected Bend ... yes yes I know limit point should work irrespective but in practice I think you get "tuned" to bends you know. And this is partly the reason you get monaed at when you don't press on regardless at NSL on a twisty road you don't know ... the observer probably is familiar with it but ...

[Carbon Based]

this is partly the reason you get monaed at when you don't press on regardless at NSL on a twisty road you don't know ... the observer probably is familiar with it but ...

Familiarity is probably a big part. They "know" the road which means that bend where the overgrown verge limits your visability such that you feel it requires 20mph, is one at they can haul themselves round at twice that. They've also driven that bend twice a day for the last 10 years and there has never yet been an issue so it must be safe at 40mph.

If you are in anything remotely low and sporty, and they are in a typical white van or 4x4 they will have a substantially higher eye level than you so their limit point will be different to yours for the same bend.

And, although they may not be aware of it, they may only going as fast as they are because you are just in front of them. They are subconsciously using you to clear the way. Yet they think you are holding them up.

[superplum]

this is partly the reason you get monaed at when you don't press on regardless at NSL on a twisty road you don't know ... the observer probably is familiar with it but ...

If you are in anything remotely low and sporty, and they are in a typical white van or 4x4 they will have a substantially higher eye level than you so their limit point will be different to yours for the same bend.

The limit point hardly changes with height and doesn't cut across verges - it's the tarmac you can see to be clear. If you are in something low and sporty, try standing up (stationary of course ) to see what difference it makes.

[hir]

http://roadarbloggers.wordpress.com/2011/03/18/corners-and-cornering/

Exactly. On a LH bend the true limit point is the LH side (which you can't see).

The photograph shown on roadarbloggers illustrates the point well. But, it also overstates the problem. No one in their right mind (not even a biker ) would place their vehicle so far over the white line in the position from which the photograph was taken on that particular left-hander.

[Grahar]

And, although they may not be aware of it, they may only going as fast as they are because you are just in front of them. They are subconsciously using you to clear the way. Yet they think you are holding them up.

This is a very good point. It is a common self-delusion that drivers have. I think the problem is compounded because as advanced drivers (particularly if you are driving a manual and you require a gearchange) our approach is typically 'slow in, fast out'.

I find that the ground you make up on the way out sometimes causes the following driver to try and catch up which results in them being all over you going into the next bend. The delusion is increased if you are driving a more powerful car than the one following, as they think that the ground you make up out of the bend is all down to power rather than careful limit point analysis. As a result I feel they are less likely to 'catch on' that your fast exit is greatly aided by a slow entry and swift application of acceleration as soon as the limit point starts moving.

[Gareth]

There is also a world of difference between The Bend You Know, the Bend That Is New

If there's any difference in how you approach the bend you know and the one you don't, then there's probably something wrong with the approach for one of them. It's mostly a matter with being honest with yourself about what you can and can't see ...

If you find yourself going faster for bends you know, it's time to step back and approach it (them) from first principles.

[fungus]

And, although they may not be aware of it, they may only going as fast as they are because you are just in front of them. They are subconsciously using you to clear the way. Yet they think you are holding them up.

This is a very good point. It is a common self-delusion that drivers have. I think the problem is compounded because as advanced drivers (particularly if you are driving a manual and you require a gearchange) our approach is typically 'slow in, fast out'.

I find that the ground you make up on the way out sometimes causes the following driver to try and catch up which results in them being all over you going into the next bend. The delusion is increased if you are driving a more powerful car than the one following, as they think that the ground you make up out of the bend is all down to power rather than careful limit point analysis. As a result I feel they are less likely to 'catch on' that your fast exit is greatly aided by a slow entry and swift application of acceleration as soon as the limit point starts moving.

That is exactly my experience, even in my modest 1.4 Fiesta.

There is also a world of difference between The Bend You Know, the Bend That Is New

If there's any difference in how you approach the bend you know and the one you don't, then there's probably something wrong with the approach for one of them. It's mostly a matter with being honest with yourself about what you can and can't see ...

If you find yourself going faster for bends you know, it's time to step back and approach it (them) from first principles.

Exactly. Isn't the fact that most accidents happen near to home on roads that the driver knows, down to complacency.

[trashbat]

Or because that's where they live?

I don't expect I'll have many road accidents in Japan any time soon.

This thread seems a bit bizarre to me - how we can drag out such an apparently simple point to such lengths.

[Horse]

http://roadarbloggers.wordpress.com/2011/03/18/corners-and-cornering/

Exactly. On a LH bend the true limit point is the LH side (which you can't see).

The photograph shown on roadarbloggers illustrates the point well. But, it also overstates the problem. No one in their right mind (not even a biker ) would place their vehicle so far over the white line in the position from which the photograph was taken on that particular left-hander.

The photo was taken from the pavement

However, that is irrelevant; whether you take a wide line, track the centre line, take a mid-lane line all the way through the bend parallel to the verge, or even hug the nearside hedge, the true limit is the nearest you can see on the left, ie the Surprise Horizon.

[triquet]

I like Surprise Horizon. It is exactly how I feel it needs to be considered.

[hir]

The photo was taken from the pavement

There is no pavement.

However, that is irrelevant; whether you take a wide line, track the centre line, take a mid-lane line all the way through the bend parallel to the verge, or even hug the nearside hedge, the true limit is the nearest you can see on the left, ie the Surprise Horizon.

As others have said... I can't understand why we're wasting so much time stating the b.......g obvious.

I can't believe anyone who uses limit point technique actually has a problem in deciding where the actual relevant limit point is in relation to their ability to stop in that distance. Nobody actually believes that the relevant limit point is on the other side of the road! I thought I was a pedant, but this discussion now exceeds all known limits of pointless pedantry.

[triquet]

"Nobody actually believes that the relevant limit point is on the other side of the road! "

Of course not, if you are a thinking person. But perhaps the little diagrams in Roadcraft and HTBABD need revision. It's the typical AD piffle to write down something and expect something different in practice. A bit like "speed limits are not targets ... ". But I'm not going to have a Monday morning rant so I'll toddle off and get me coat ...

[MGF]

I think it's useful to have both bits for a new ADer.

One asks them to look.
The other asks them to think.

Both are important.

If you are looking for a rule to supplement the 'golden rule' , to make it more useful in choosing an appropriate speed, then that can be stated quite simply. For example,

... stop in the distance you can see to be clear and are sure will stay clear...

Asking someone if they 'are sure' is likely to make them think. Asking if they 'can reasonably expect something to happen, is likely to make them wonder what you are asking them.

I can reasonably expect a road to reamain clear at the same time as reasonably expecting it not to. It is meaningless and appears to be the consequence of an attempt to copy and past bits of Roadcraft together to give the statement some authority.

Similarly there is no need to claim it is the 'golden rule'. It is a statement that either stands or falls on its content and meaning.