Motorway 'safe' distance chevrons
Discussion
0000 said:
No.
You've been talking about 7 seconds gap at 70mph, not 7 seconds at, say, an average of 35mph (not accounting for reaction time and assuming linear deceleration).
Yes I agree with that, I realise that you will be slowing hard from seventy downwards when doing an emergency stop, I said that in a post before you posted this.You've been talking about 7 seconds gap at 70mph, not 7 seconds at, say, an average of 35mph (not accounting for reaction time and assuming linear deceleration).
I've never disputed that my large gap is way more than the recommended, although I'd have thought a class 1 police IAM examiner would have taken issue with it if it's as bad as is being implied here. Most recently in 2011 for the record, not in the 1950s. But I suppose 35 years as class 1 doesn't equate to knowing anything in people's eyes here. what I am asking is whether 62 metres is enough at 70? (Enough of the time bs, time/metres it equates to the same thing)Everything I can find says a resounding no! The exception being here in this thread of course.
25NAD90TUL said:
No I didn't miss that but to me that's just splitting hairs, what difference does it make how I calculate it, time=distance travelled period.
And you a doctor in environmental physics - for shame...Time x average speed = distance travelled. If you have to brake to a halt then your average speed (assuming a linear deceleration rate, which is perfectly reasonable at the speeds we're discussing) is half of the speed you're travelling at initially, so your distances are overly conservative.
Now running through the list of various bits and pieces:
1. The Highway Code stopping distances are engineered to be about right and easy to remember. IIRC it equates to about 0.68s reaction time (potentially a bit hopeful) and a deceleration rate of about 0.68g. Even vehicles of the 1950s with all four wheels locked can achieve that deceleration rate.
2. A two second gap to the vehicle in front is perfectly safe, most of the time. It assumes that a) all the traffic will be able to decelerate at the same speed (i.e. no stationary objects appearing magically on the carriageway) so that it's there to absorb the distance between you and the car in front during your thinking time. If you're hard of thinking then you'll need longer. In general this is perfectly OK as stationary objects rarely appear.
3. The issue with such a long gap to the vehicle in front is what you do when someone fills that gap (If the vehicle approaching from behind is 100m away, I'm pretty sure I'd fill that gap, let alone the 200+m you advocate). The other road users may see you effectively lifting off for no apparent reason and from there red mist/road rage/undertaking may occur. If you sit in lane 1 and do it, I don't see there being an issue - it's more than a bit oddball, but each to their own. In lane 3, lifting to create say another 100m of gap is not giving reasonable consideration to other road users.
25NAD90TUL said:
StressedDave said:
The bit in brackets is actually the more important bit. A 7 second gap equates to a smidgin over 219m. Allowing for a 2 second reaction time (generous), the total stopping distance from 70 mph is a smidgin under 134m. Any more reaction time is treading in the realms of carelessness, so you're wasting 85m of road unnecessarily.
Stop getting hooked up on time - it's the wrong approach. No one cares how long it takes to get to a point on the road. They do care that if they're stationary at that point, you'll not hit them.
Forgive me because I'm getting confused, to me it looks like you are saying 6.5 seconds required to stop and in the next breath you state a distance which doesn't equate to 6.5 seconds in terms of distance travelled at 70, I realise that upon applying the brakes you will be decelerating hard from 70 downwards, so won't be doing 70 for the whole 6.5 seconds.Stop getting hooked up on time - it's the wrong approach. No one cares how long it takes to get to a point on the road. They do care that if they're stationary at that point, you'll not hit them.
Not being dis-respectful or arguing for the sake of it, I need clarification on this, so you are saying that what I quoted from the Highway Code is not correct in your view and the full stopping distance recommended in the book as the safe following distance is not what you are recommending I use as a minimum?
My reaction times aren't too bad, but I don't want to start relying on them for my survival, in case they are not as good as I imagine. Finally do you consider a following distance of two seconds at 70mph to be adequate?
Edited to add: The bracketed part of your post? Seconds/metres it amounts to the same distance, to me the seconds thing is just a good way of measuring the distance while driving, seconds/metres surely that is just splitting hairs...
Everything I have ever done, read, been taught, used on test is being thrown into disrepute here, it looks to me as though even the Highway Code's advice is being cancelled out, this what get's me about AD, so much conflicting stuff, Christ I have a mate who's a bobby who regularly accompanies me and who considers my thinking sound, how many mway patrols I must have passed when using a 7 second gap, or 215 metres if you prefer that nomenclature must I have passed in my career doesn't bear thinking about and never once been pulled or even had a sideways glance.
Best wishes Dave and seriously I'm not messing about here or bickering for the sake of it, this to me is a serious safety issue we're discussing.
Edited by 25NAD90TUL on Wednesday 15th January 09:25
Leaving a seven second gap will increase your chances of encountering road rage from following drivers.
On a two lane road do you require a clear seven seconds before you pull back in to L1 after completing a pass?
StressedDave said:
3. The issue with such a long gap to the vehicle in front is what you do when someone fills that gap (If the vehicle approaching from behind is 100m away, I'm pretty sure I'd fill that gap, let alone the 200+m you advocate). The other road users may see you effectively lifting off for no apparent reason and from there red mist/road rage/undertaking may occur. If you sit in lane 1 and do it, I don't see there being an issue - it's more than a bit oddball, but each to their own. In lane 3, lifting to create say another 100m of gap is not giving reasonable consideration to other road users.
Ah! That's probably what WinstonWolf was getting at on page 3 with "opens you up to prosecution" isn't it.johnao said:
...you say NO (because you do not agree with any of the counter arguments put forth).
In fact it's a case of the counter arguments being contrary to what is suggested as safe in the Highway Code. Perhaps you think I've made all this up, or that it is just my opinion, it isn't, according to the Highway Code you should consider the full stopping distance of 96 metres at 70mph to be the safe following distance. Now that clearly is NOT two seconds or 62 metres. If you want the exact wording I quoted it verbatim earlier in this thread. I can only put forward the facts as stated in the books I quoted from, and regarding your instruction, johnao, if that's what it was, I had already bowed out temporarily and stated such publicly, well before your post, as you would have seen had you not just made a reactionary post without reading further.
SK425 said:
StressedDave said:
3. The issue with such a long gap to the vehicle in front is what you do when someone fills that gap (If the vehicle approaching from behind is 100m away, I'm pretty sure I'd fill that gap, let alone the 200+m you advocate). The other road users may see you effectively lifting off for no apparent reason and from there red mist/road rage/undertaking may occur. If you sit in lane 1 and do it, I don't see there being an issue - it's more than a bit oddball, but each to their own. In lane 3, lifting to create say another 100m of gap is not giving reasonable consideration to other road users.
Ah! That's probably what WinstonWolf was getting at on page 3 with "opens you up to prosecution" isn't it.I am completely clear, as I have sought advice on this, on the following points:
My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
This is the SINGLE only issue I have with AD, that so many people within it are prepared to contradict even what is said in the Highway Code, I can accept arguments over certain aspects of the AD literature, such as the finer points of the system regarding things like bgol but this is too much.
I quote verbatim while adding my own emboldening:
'The safe rule is never to get closer than the overall stopping distance...'
Your two second rule is considered inadequate in AD literature, actually you are considered, and I quote: 'deluded' if you think it is, but then what do they know? Clearly very little in the eyes of some here.
So that's it, I'm out now, I'm clear on where I stand and have nothing further to add.
My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
This is the SINGLE only issue I have with AD, that so many people within it are prepared to contradict even what is said in the Highway Code, I can accept arguments over certain aspects of the AD literature, such as the finer points of the system regarding things like bgol but this is too much.
I quote verbatim while adding my own emboldening:
'The safe rule is never to get closer than the overall stopping distance...'
Your two second rule is considered inadequate in AD literature, actually you are considered, and I quote: 'deluded' if you think it is, but then what do they know? Clearly very little in the eyes of some here.
So that's it, I'm out now, I'm clear on where I stand and have nothing further to add.
25NAD90TUL said:
I am completely clear, as I have sought advice on this, on the following points:
My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
This is the SINGLE only issue I have with AD, that so many people within it are prepared to contradict even what is said in the Highway Code, I can accept arguments over certain aspects of the AD literature, such as the finer points of the system regarding things like bgol but this is too much.
I quote verbatim while adding my own emboldening:
'The safe rule is never to get closer than the overall stopping distance...'
Your two second rule is considered inadequate in AD literature, actually you are considered, and I quote: 'deluded' if you think it is, but then what do they know? Clearly very little in the eyes of some here.
So that's it, I'm out now, I'm clear on where I stand and have nothing further to add.
My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
This is the SINGLE only issue I have with AD, that so many people within it are prepared to contradict even what is said in the Highway Code, I can accept arguments over certain aspects of the AD literature, such as the finer points of the system regarding things like bgol but this is too much.
I quote verbatim while adding my own emboldening:
'The safe rule is never to get closer than the overall stopping distance...'
Your two second rule is considered inadequate in AD literature, actually you are considered, and I quote: 'deluded' if you think it is, but then what do they know? Clearly very little in the eyes of some here.
So that's it, I'm out now, I'm clear on where I stand and have nothing further to add.
You are a MLM and you can't or won't see it. You certainly are not an AD.
25NAD90TUL said:
I am completely clear, as I have sought advice on this, on the following points:
My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
A big gap is not illegal, and no-one (hopefully) has suggested thus. However, what you have to do to maintain such a gap, and whereabouts on the motorway you do so, may be sufficient to contradict the Road Traffic Act. As a purely gratuitous example:My maintaining a seven second or 215 metre gap at 70mph IN ANY LANE is NOT ILLEGAL IN ANY WAY, neither do I have to compromise it on the grounds that someone else may commit a criminal act such as road-rage, tailgating etc, the Highway Code DOES NOT consider anything less than a MINIMUM of the FULL stopping distance at 70mph as being safe and the HC isn't AD it's just standard level. I'm clear on all these points now thanks. As for the ludicrous 'pace-setting/without insurance' comment I'm just going to ignore that, it isn't worth a response.
You happen to be in lane 3, with a 7 second gap to the vehicle in front, so some 219.05m. A driver some 65m (i.e two seconds ahead) pulls out in front. All this is in accordance with HC. You want a 7 second gap, so you need to have a speed differential to the vehicle in front in order to achieve this. Say you lift slightly down to 69mph. You are setting a pace for the vehicles behind (potentially: I'd say this would be a difficult one to enforce on the part of the BiB - I've seen it done, but it's very rare). You may or may not be overtaking an adjacent vehicle now (In finest elephant racing tradition the car adjacent is doing 69.1 mph) so not conforming to rule 264. At a 1 mph differential, to regain the extra 154.05m, will take 344.60 seconds or about 5 3/4 minutes. So it will take some 6.7 miles to do this.
This is purely gratuitous - you've not explained at any point how you regain the gap you want.
25NAD90TUL said:
This is the SINGLE only issue I have with AD, that so many people within it are prepared to contradict even what is said in the Highway Code, I can accept arguments over certain aspects of the AD literature, such as the finer points of the system regarding things like bgol but this is too much.
Doesn't the Highway Code state that a two second gap is sufficient, or are you conveniently glossing over that particular paragraph (it's paragraph 126 if you care to look)25NAD90TUL said:
StressedDave said:
Doesn't the Highway Code state that a two second gap is sufficient, or are you conveniently glossing over that particular paragraph (it's paragraph 126 if you care to look)
Are you conveniently glossing over that paragraph above it? Paragraph 126 if you care to look.I've said umpteen times right from the beginning that I am more than happy to drop out, into lane 1 if necessary, making your point useless. I'm not arguing anymore, you're being ridiculous.
StressedDave said:
You are setting a pace for the vehicles behind (potentially: I'd say this would be a difficult one to enforce on the part of the BiB - I've seen it done, but it's very rare).
Out of interest, what's the potential offence there? Is it a form of careless driving, or is pace setting a specific offence in its own right? Does 'pace setting' mean holding people up behind you?Gassing Station | Advanced Driving | Top of Page | What's New | My Stuff