Discussion
I had my first IAM observed run today with the Mid-Kent group, and very enjoyable it was too.
While out on the run my observer picked up on BGOL when approaching a hazard which requires a stop from a high gear, usually from 4th or 5th into 2nd or 3rd. The problem I think is mentally accepting depressing the clutch at 15-20mph (the minimum speed in 4th/5th before the engine starts to struggle) and effectively coasting to a halt, which when braking gently may cover 20-25m. When approaching a similar hazard, but from a lower speed (say 2nd gear) this isn't a problem because idle in second gear is <10mph so the distance covered from depressing the clutch to stopping is significantly reduced.
As it happens Trevor Dickenson (IAM Staff Examiner) was there and after we got back I had a chat with him about it and he said that the IAM don't recognise coasting, presumably on the understanding that modern brakes are fade-free enough to reply upon. At present it feels unnatural and not what I was taught when I learnt to drive, but I'm sure I'll get used to it.
Do RoADA and HPC also regard coasting as safe, and if not do they an alternative to either the BGOL or interupting braking to make a gear change to prevent coasting to a halt?
While out on the run my observer picked up on BGOL when approaching a hazard which requires a stop from a high gear, usually from 4th or 5th into 2nd or 3rd. The problem I think is mentally accepting depressing the clutch at 15-20mph (the minimum speed in 4th/5th before the engine starts to struggle) and effectively coasting to a halt, which when braking gently may cover 20-25m. When approaching a similar hazard, but from a lower speed (say 2nd gear) this isn't a problem because idle in second gear is <10mph so the distance covered from depressing the clutch to stopping is significantly reduced.
As it happens Trevor Dickenson (IAM Staff Examiner) was there and after we got back I had a chat with him about it and he said that the IAM don't recognise coasting, presumably on the understanding that modern brakes are fade-free enough to reply upon. At present it feels unnatural and not what I was taught when I learnt to drive, but I'm sure I'll get used to it.
Do RoADA and HPC also regard coasting as safe, and if not do they an alternative to either the BGOL or interupting braking to make a gear change to prevent coasting to a halt?
On the L test, I was told that when coasting, you are not in control of the vehicle. And true that may be, but when you come to a stop/walking speed from in 5th gear, you are either on the brake or changing to a lower gear. Either way, you are in control of the car, as you have control of both the clutch and the brakes.
Slowing to 10-15mph in 5th does not sound nice, and no one would expect you to do it. If one did, it would go down as a -1 on mechanical sympathy.
Glad to hear your first session went well! It gets better!
Slowing to 10-15mph in 5th does not sound nice, and no one would expect you to do it. If one did, it would go down as a -1 on mechanical sympathy.
Glad to hear your first session went well! It gets better!
You're not actually coasting ... at least not in the ad. driving world.
If you had clutch down and no brakes, this would be termed as coasting, and is a no no, less creeping in heavy traffic when it sometimes can't be avoided.
In your case, clutch down at 15-20 mph, but you are on the brakes, which is providing a controlling force on the car, and so is not considered coasting, simple as that.
Hope this helps,
Martin
If you had clutch down and no brakes, this would be termed as coasting, and is a no no, less creeping in heavy traffic when it sometimes can't be avoided.
In your case, clutch down at 15-20 mph, but you are on the brakes, which is providing a controlling force on the car, and so is not considered coasting, simple as that.
Hope this helps,
Martin
LaSarthe+Back said:
On the L test, I was told that when coasting, you are not in control of the vehicle. And true that may be, but when you come to a stop/walking speed from in 5th gear, you are either on the brake or changing to a lower gear. Either way, you are in control of the car, as you have control of both the clutch and the brakes.
Slowing to 10-15mph in 5th does not sound nice, and no one would expect you to do it. If one did, it would go down as a -1 on mechanical sympathy.
Glad to hear your first session went well! It gets better!
... Slowing to 10-15mph in 5th does not sound nice, and no one would expect you to do it. If one did, it would go down as a -1 on mechanical sympathy.Slowing to 10-15mph in 5th does not sound nice, and no one would expect you to do it. If one did, it would go down as a -1 on mechanical sympathy.
Glad to hear your first session went well! It gets better!
On this point, which is a good one, you need to start getting the clutch down before the revs get to where ever they would be when idling. Providing you do this, there is no harm to the vehicle. Of course the higher the gear, the earlier this has to take place.
Martin
And to answer other part of the OP's question, the other advanced driving organisations that you mention recommend the same system of driving - don't change gear until you know the speed for the hazard, then block change to the most suitable gear to go into and through the hazard. All these organisations base their teaching on Roadcraft, the police driver's handbook, with input from current and former police drivers, and so teach the same system of driving.
Thanks for the replies, I'd always taken coasting to movement of the car while a gear wasn't selected; I wonder if yesterday I was in the situation where I could just roll up to traffic and therefore wasn't on the brakes after depressing the clutch. I'll have a look at what I'm doing in that situation on my way into work this morning.
I'm not entirely sure where your 10-15mph came from. I stated 15-20, I've just done the maths & it will be ~23mph @800rpm in 5th, so my initial figures were slightly out.
I'm not entirely sure where your 10-15mph came from. I stated 15-20, I've just done the maths & it will be ~23mph @800rpm in 5th, so my initial figures were slightly out.
It depends to some degree on how quickly you are coming to a halt as determined by the circumstances and the nature of the hazard. If it is a simple brake to a halt from 50mph to a junction, then there is usually no problem at all having the clutch depressed and being on the brakes even if it feels odd first of all.
If the circumstances are different maybe with a highly geared diesel in 6th and some slow moving traffic before the junction you are stopping for so that the period on the clutch is excessive, then you usually have the opportunity to take an intermediate gear.
It might naturally break down into two hazards, so you brake, select intermediate gear and then brake some more.
You might select the lower gear before braking (my favourite, but possibly not de rigeur) eg 70 in 6th on motorway, slow to 50 before taking downhill exit slip, then stopping at the end of the slip. The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
Also, if safety dictates, you can do a BGOL, but the idea is that it is the exception rather than the rule.
Bert
If the circumstances are different maybe with a highly geared diesel in 6th and some slow moving traffic before the junction you are stopping for so that the period on the clutch is excessive, then you usually have the opportunity to take an intermediate gear.
It might naturally break down into two hazards, so you brake, select intermediate gear and then brake some more.
You might select the lower gear before braking (my favourite, but possibly not de rigeur) eg 70 in 6th on motorway, slow to 50 before taking downhill exit slip, then stopping at the end of the slip. The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
Also, if safety dictates, you can do a BGOL, but the idea is that it is the exception rather than the rule.
Bert
Vaux said:
BertBert said:
....The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
You're slowing on the main carriageway? I hope there's nothing close behind you.Bert
BertBert said:
Vaux said:
BertBert said:
....The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
You're slowing on the main carriageway? I hope there's nothing close behind you.Bert
BOF
BertBert said:
Vaux said:
BertBert said:
....The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
You're slowing on the main carriageway? I hope there's nothing close behind you.Bert
Holst said:
I find it easyer to change down into 4th (from 5th) before some hazzard and before I start braking, this makes it easyer to change down to 2nd or 3rd once braking is complete as I dont have to coast for as long, if at all. Is this OK?
What! Are you saying it takes you longer to move the gear stick from 5th than 4th?You seem to have a misapprehension of what coasting is. If you're braking you're not coasting.
Basically it sounds like you'd be making an unnecessary gear change which would generally be regarded as "wrong" in IAM/RoADA tests.
JimboCam said:
BertBert said:
Vaux said:
BertBert said:
....The first hazard is the start of the slip, so you reduce speed from 70 to say 50, select 4th. Then it all works better at the end of the slip.
You're slowing on the main carriageway? I hope there's nothing close behind you.Bert
aha, to add to or clear up the confusion...I didn't say you should decelerate for any or all exit slips.
The original context was a concern about being in a high gear (clutch disengaged) when coming to a halt. I commented that it worked ok if you had a straight deceleration from speed at the higher gear to a stop. I also said that if the deceleration took longer, for example with slower traffic, you could end up in a high gear, clutch disengaged for an elongated period. In the latter circs you should seek to engage an intermediate gear.
The example I gave was that of slowing before the entry to a slip road and taking the intermediate gear without a BGOL.
So why would you want to slow before entering a slip? Who knows?
Slower traffic just entering the slip
A short blind wet downhill slip
A slip with road works that reduces from 2 lanes to 1
Doesn't matter really what the example is, it was just to illustrate the point.
BTW the example my IAM observer took me through was the northbound exit slip off the A3 at Esher.
Bert
The original context was a concern about being in a high gear (clutch disengaged) when coming to a halt. I commented that it worked ok if you had a straight deceleration from speed at the higher gear to a stop. I also said that if the deceleration took longer, for example with slower traffic, you could end up in a high gear, clutch disengaged for an elongated period. In the latter circs you should seek to engage an intermediate gear.
The example I gave was that of slowing before the entry to a slip road and taking the intermediate gear without a BGOL.
So why would you want to slow before entering a slip? Who knows?
Slower traffic just entering the slip
A short blind wet downhill slip
A slip with road works that reduces from 2 lanes to 1
Doesn't matter really what the example is, it was just to illustrate the point.
BTW the example my IAM observer took me through was the northbound exit slip off the A3 at Esher.
Bert
JimboCam said:
Holst said:
I find it easyer to change down into 4th (from 5th) before some hazzard and before I start braking, this makes it easyer to change down to 2nd or 3rd once braking is complete as I dont have to coast for as long, if at all. Is this OK?
What! Are you saying it takes you longer to move the gear stick from 5th than 4th?You seem to have a misapprehension of what coasting is. If you're braking you're not coasting.
Basically it sounds like you'd be making an unnecessary gear change which would generally be regarded as "wrong" in IAM/RoADA tests.
I mean to say, the IAM/RoSPA considers it 'wrong', so that's the end of the matter, is it? Well I suppose it is if you wish to pass their tests, but aside from that, just how much do some of these niceties really matter?
Quite frankly I think we make far too much fuss about some of these trifling details, and whilever that continues we should not be surprised to find so many people being deterred from taking an interest in advanced driving, and I can't blame them.
First of all, what is a proper definition of coasting? If we're going have all this knicker knotting about it, we'd better know just what is meant by coasting, had we not? I get fed up of this hogwash about coasting, and how evil it is - 'vehicle not under control' they say. As far as I'm concerned, if the vehicle is going where the driver intends it to go, and it's travelling at a speed he judges to be suitable, and it is not in danger of going where it shouldn't go, or travelling at speeds that are unsuitable, it jolly well is under control, and it doesn't matter whether or not the driver is braking, or whether it is in gear or in neutral - so long as he retains the ability to alter its course and/or speed promptly to suit a changing situation. What else do we need?
If we really want to get into all the wearisome details of all this, we'd better be clear about what coasting means, for a start.
Best wishes all,
Dave.
p1esk said:
JimboCam said:
Holst said:
I find it easyer to change down into 4th (from 5th) before some hazzard and before I start braking, this makes it easyer to change down to 2nd or 3rd once braking is complete as I dont have to coast for as long, if at all. Is this OK?
What! Are you saying it takes you longer to move the gear stick from 5th than 4th?You seem to have a misapprehension of what coasting is. If you're braking you're not coasting.
Basically it sounds like you'd be making an unnecessary gear change which would generally be regarded as "wrong" in IAM/RoADA tests.
I mean to say, the IAM/RoSPA considers it 'wrong', so that's the end of the matter, is it? Well I suppose it is if you wish to pass their tests, but aside from that, just how much do some of these niceties really matter?
Quite frankly I think we make far too much fuss about some of these trifling details, and whilever that continues we should not be surprised to find so many people being deterred from taking an interest in advanced driving, and I can't blame them.
First of all, what is a proper definition of coasting? If we're going have all this knicker knotting about it, we'd better know just what is meant by coasting, had we not? I get fed up of this hogwash about coasting, and how evil it is - 'vehicle not under control' they say. As far as I'm concerned, if the vehicle is going where the driver intends it to go, and it's travelling at a speed he judges to be suitable, and it is not in danger of going where it shouldn't go, or travelling at speeds that are unsuitable, it jolly well is under control, and it doesn't matter whether or not the driver is braking, or whether it is in gear or in neutral - so long as he retains the ability to alter its course and/or speed promptly to suit a changing situation. What else do we need?
If we really want to get into all the wearisome details of all this, we'd better be clear about what coasting means, for a start.
Best wishes all,
Dave.
To me coasting is when both the engine and brakes are disengaged.
BertBert said:
aha, to add to or clear up the confusion...I didn't say you should decelerate for any or all exit slips.
Well, that's what you seemed to be saying.BertBert said:
The original context was a concern about being in a high gear (clutch disengaged) when coming to a halt. I commented that it worked ok if you had a straight deceleration from speed at the higher gear to a stop. I also said that if the deceleration took longer, for example with slower traffic, you could end up in a high gear, clutch disengaged for an elongated period. In the latter circs you should seek to engage an intermediate gear.
Yeah sure, if circumstances dictate then you might well engage an intermediate gear.BertBert said:
The example I gave was that of slowing before the entry to a slip road and taking the intermediate gear without a BGOL.
So why would you want to slow before entering a slip? Who knows?
Slower traffic just entering the slip
A short blind wet downhill slip
A slip with road works that reduces from 2 lanes to 1
Then you have multiple hazards. If you wanted better control over your speed you could always go down a gear while maintaining the same speed on the main carriageway.So why would you want to slow before entering a slip? Who knows?
Slower traffic just entering the slip
A short blind wet downhill slip
A slip with road works that reduces from 2 lanes to 1
BertBert said:
Doesn't matter really what the example is, it was just to illustrate the point.
BTW the example my IAM observer took me through was the northbound exit slip off the A3 at Esher.
Bert
Well, it wasn't a very good example IMHO! Can't see any need for premature deceleration.BTW the example my IAM observer took me through was the northbound exit slip off the A3 at Esher.
Bert
http://maps.google.co.uk/maps?f=q&hl=en&ge...
Jimbocam, please accept my apologies. I am truly sorry that my example didn't live up to the required standard of PH examples. I am also supremely impressed that with a quick butchers at google maps, you are able to establish the correct speed for the entry to that slip under all possible circumstances. I bow to your superior abilities.
Bert
Bert
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