Second thoughts on offsiding

Topics relating to Advanced Driving in cars
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M1ke H
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Re: Second thoughts on offsiding

Postby M1ke H » Tue Aug 07, 2018 4:17 pm

I'm not so sure about 'slippery substances', but locally the road edges are in an appalling state, to the extent that Joe Public is often driving just left of or even over the centre white line on your average B or C road in order to avoid the potholes, subsidence, and surface "imperfections". Off siding locally therefore becomes more of an issue due to off side potholes etc :shock:

(I'm not entirely convinced it's not a ploy by BRAKE supporters on the council to prevent overtaking... ;) )

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akirk
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Re: Second thoughts on offsiding

Postby akirk » Tue Aug 07, 2018 4:40 pm

Astraist wrote:
akirk wrote:added stability = added speed
added stability = added contingency (e.g. in the event of a blowout)

for me a lot of driving is about adding the ability for speed or contingency - if you can add both, then happy days - otherwise, it tends to be a choice between choosing speed or contingency...


Exactly, contingency. But for what? Not for cornering capacity at speed because if one intentionally offsiding, one would know better; not for being able to safely stop in the clear road section ahead, because if one offsiding, that's clearly not an issue from the outset; not for defensive purposes (i.e. another road user using more than their fair share of the road) because offsiding isn't performed in the presence of other road users.

So that leaves us with contingency for a sudden, unforseen reduction in road holding. The main cause of that being an unforseen, slippery part of the road. But than, if we're using twice the road width, we're increasing the possibility of hitting such a section of road, which may occur on just one of the two lanes, or just around the centerline.


Contingency for anything that is in that category of random / couldn't be predicted...
suspension fault / wheel blowout / pheasant being shot and falling on your car / sinkhole opening up / etc.
with any of them, you are more stable = good thing.
even if there is zero chance of something happening - more stability for no other detriment is always a good thing, if nothing else, it gives you the option of more speed :)

and as mentioned above - a car of 6 foot width can only use 6 foot width where-ever it is on the road - having twice as much width of road available to you as the driver doesn't mean that you can use twice as much - you can still only use the same amount... So if the road is 18 foot wide, you can only use 6 foot of that width whether that is left third / middle third / right-hand third - therefore you have exactly the same risk if a hazard could be randomly on the road, you still have a 1 in 3 chance of hitting it... therefore, unless this unseen hazard has a higher chance of being in one place or another, you can not increase the chance of hitting it by choosing a different part of the road...

Alasdair

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akirk
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Re: Second thoughts on offsiding

Postby akirk » Tue Aug 07, 2018 4:41 pm

M1ke H wrote:I'm not so sure about 'slippery substances', but locally the road edges are in an appalling state, to the extent that Joe Public is often driving just left of or even over the centre white line on your average B or C road in order to avoid the potholes, subsidence, and surface "imperfections". Off siding locally therefore becomes more of an issue due to off side potholes etc :shock:

(I'm not entirely convinced it's not a ploy by BRAKE supporters on the council to prevent overtaking... ;) )


not sure that offsiding should take you as far as the pothole verge on the other side of the road...

Alasdair

Astraist
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Re: Second thoughts on offsiding

Postby Astraist » Tue Aug 07, 2018 5:48 pm

akirk wrote:with any of them, you are more stable = good thing.


Oh, I agree.

akirk wrote: unless this unseen hazard has a higher chance of being in one place or another.


But it often does. Superelevation, the transition from road crown to and from superelevation and the change in the degree of superelevation across the width of the roadway all make it more likely for the road to be slippery at the inner circumference of the corner. In terms of ice (not a worry here, but relevant for coaching people who will be driving abroad), its more likely to form at the centerline which is colder than the parts that are constantly travelled by vehicles, etc...

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akirk
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Re: Second thoughts on offsiding

Postby akirk » Tue Aug 07, 2018 7:46 pm

Astraist wrote:
akirk wrote: unless this unseen hazard has a higher chance of being in one place or another.


But it often does. Superelevation, the transition from road crown to and from superelevation and the change in the degree of superelevation across the width of the roadway all make it more likely for the road to be slippery at the inner circumference of the corner. In terms of ice (not a worry here, but relevant for coaching people who will be driving abroad), its more likely to form at the centerline which is colder than the parts that are constantly travelled by vehicles, etc...


Fair points - but hopefully ones that would be considered by the driver - e.g. the centre line is always likely to be a different surface to the rest, so in off-siding I would consider the impact of the moment when that is crossed (and on return) - but actually running off-side may mean wheels across on the both carriageways and straddling the centre line where it has no impact, for me off-siding doesn't take me into the inner circumference of a corner - it is in fact more likely to move me away from it...

Alasdair

ancient
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Re: Second thoughts on offsiding

Postby ancient » Wed Aug 08, 2018 8:09 am

Astraist wrote:[
akirk wrote: unless this unseen hazard has a higher chance of being in one place or another.


But it often does. Superelevation, the transition from road crown to and from superelevation and the change in the degree of superelevation across the width of the roadway all make it more likely for the road to be slippery at the inner circumference of the corner. In terms of ice (not a worry here, but relevant for coaching people who will be driving abroad), its more likely to form at the centerline which is colder than the parts that are constantly travelled by vehicles, etc...

I have known oil spills to sit on the crown of the road and in the raised middle of a roundabout. Generally IME oil makes slippery where it is spilled and does not run to a low point in the road. Perhaps where you are, the climatic conditions cause oil to pool on the low side of the road, but not here.
Similarly I have known ice to form in sunken pickets and I have known it to form on raised portions of the road which are more exposed.
It is simply not true that either side of a random bend will be more likely to be slippery. If a bend is known to be slippery on one part, that part is best avoided where possible (but it is as likely to be the nearside as the off side).

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Horse
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Re: Second thoughts on offsiding

Postby Horse » Wed Aug 08, 2018 8:42 am

akirk wrote: not sure that offsiding should take you as far as the pothole verge on the other side of the road...


If ignoring a marked (albeit 'soft') divider, why limit yourself to just part of the opposing lane?
My own views. For better or worse :)

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M1ke H
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Re: Second thoughts on offsiding

Postby M1ke H » Wed Aug 08, 2018 12:34 pm

akirk wrote:
M1ke H wrote:I'm not so sure about 'slippery substances', but locally the road edges are in an appalling state, to the extent that Joe Public is often driving just left of or even over the centre white line on your average B or C road in order to avoid the potholes, subsidence, and surface "imperfections". Off siding locally therefore becomes more of an issue due to off side potholes etc :shock:

(I'm not entirely convinced it's not a ploy by BRAKE supporters on the council to prevent overtaking... ;) )


not sure that offsiding should take you as far as the pothole verge on the other side of the road...

Alasdair


Just to qualify my comment further, some of the potholes/verge subsidence locally, extends well into 3-4ft of road space (out from the kerb)!

Glos CC don't seem particularly interested especially judging on the time taken to action some 'mineshafts' after being reported. :roll:

Astraist
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Re: Second thoughts on offsiding

Postby Astraist » Wed Aug 08, 2018 12:36 pm

ancient wrote:I have known oil spills to sit on the crown of the road and in the raised middle of a roundabout.


Well, that's because the raised middle is more level.

ancient wrote:Similarly I have known ice to form in sunken pickets and I have known it to form on raised portions of the road which are more exposed.


Ice can form in any number of ways. It can freeze gradually, in which case it will be reasonable to expect it near the inside edge of the road, or it can freeze instantly in the event of freezing rain, in which case it can be in any one of the lanes - sometimes even on both.

I'm not saying that there's any one portion of the road that's categorically more likely to be slippery, but that doesn't mean that both sides of the road are always equally likely to be slippery.

And in any case, the argument still stands that by using around twice as much of the road, you're increasing your odds of surviving a sudden, unforseeable decrease in road holding, but at the expense of a higher likelihood to encounter one. You reduce the hazard, but at the cost of being exposed to it for a longer period of time.

ancient
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Re: Second thoughts on offsiding

Postby ancient » Wed Aug 08, 2018 1:47 pm

Astraist wrote:
ancient wrote:I have known oil spills to sit on the crown of the road and in the raised middle of a roundabout.


Well, that's because the raised middle is more level.

ancient wrote:Similarly I have known ice to form in sunken pickets and I have known it to form on raised portions of the road which are more exposed.


Ice can form in any number of ways. It can freeze gradually, in which case it will be reasonable to expect it near the inside edge of the road, or it can freeze instantly in the event of freezing rain, in which case it can be in any one of the lanes - sometimes even on both.

I'm not saying that there's any one portion of the road that's categorically more likely to be slippery, but that doesn't mean that both sides of the road are always equally likely to be slippery.

And in any case, the argument still stands that by using around twice as much of the road, you're increasing your odds of surviving a sudden, unforseeable decrease in road holding, but at the expense of a higher likelihood to encounter one. You reduce the hazard, but at the cost of being exposed to it for a longer period of time.

Oil makes the road slippery where it is spilled. It can be spilled on the high or low sides. It does not leave clean road when (on deep spills) it flows downward.

By offsiding you are not using twice as much road, as others have stated you use only the same width of track on the road. There is no doubled risk.

If you are taking the time exposed to risk into account, then offsiding to straightline bends will reduce the risk as your track is straighter and marginally shorter.


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