Motorway 'safe' distance chevrons

[WinstonWolf]

25NAD90TUL said:

WinstonWolf said:

It will lose speed in a slightly greater distance/time than if the driver mashed the pedal to the floor and left it there.

hair splitting aside it will not stop any quicker than the manufacturer's published stopping distance.

Put it this way it won't be a planned, controlled stop.

It won't, but as long as you start your braking in time you will be fine. If you can't begin to deploy your brakes within two seconds of something happening to the vehicle in front you are simply not observing correctly.

[25NAD90TUL]

SK425 said:

You have more than twice the Highway Code stopping distance. Can one take conservatism too far in these things? Or on the other hand, why only leave twice the HC distance when you could, to be on the even safer side, leave four times?

The vehicle ahead can only stop instantly if, as you say, it hits something solid (not sure a single vehicle, seized diff or otherwise, counts). Personally, I don't follow as far back as HC stopping distances as a matter of course as I can generally see that there isn't anything solid ahead of the vehicle in front. If I do spot something ahead, e.g. stationary traffic, I will probably open the gap up to rather more than 2 seconds.

Edited by SK425 on Monday 13th January 16:33

I'll be totally honest with you, I have the same stopping distances diagram as page two of this thread, 215 metres at 70...I'm now looking at a recent Highway Code that is saying 96 metres at 70, I'm a little confused about this, it does not however alter my feelings regarding my 7 seconds, I always think about this in terms of seconds as I can gauge my gap using the landmark method.

There is a major discrepancy between the diagram on page 2 of the thread and this 2007 HC, although it doesn't change my pov regarding the 7 second gap at 70.

[109er]

25NAD90TUL said:

109er, you have my sympathy, you don't 'drive' a 109 you 'helm' it!

Part of the logic of the large following gap is that it is there for someone to get into either in an emergency avoidance situation, or simply by accelerating into the gap, it's there for my safety and that of others.

I'm thinking of putting a sign on the back of mine with the following wording:

The gap in front of this vehicle is its safe stopping distance.
If you must enter it, be prepared to be mounted from the rear.

[0000]

25NAD90TUL said:

I'll be totally honest with you, I have the same stopping distances diagram as page two of this thread, 215 metres at 70...I'm now looking at a recent Highway Code that is saying 96 metres at 70, I'm a little confused about this

Look closer. The line above the last one is the Highway Code's. The last line is an additional comparison to show how yours compares, not the Highway Code's.

[25NAD90TUL]

WinstonWolf said:

It won't, but as long as you start your braking in time you will be fine. If you can't begin to deploy your brakes within two seconds of something happening to the vehicle in front you are simply not observing correctly.

Ah, superb, 'if you can't deploy the brakes within 2 seconds' but you have only allowed 2 seconds between the car in front remember, the 2 seconds in which you deploy is the thinking distance, this is added to the stopping distance, so at 7 seconds you have 2 seconds to think and 5 seconds to actually bring the car to a halt. Looking in those terms it isn't that much time actually.

I realise that very rarely is the vehicle in front going to come to an immediate dead stop, what I'm talking about here is the difference between just about managing to survive if you've been very lucky, compared to surviving with a fairly comfortable margin.

[WinstonWolf]

25NAD90TUL said:

WinstonWolf said:

It won't, but as long as you start your braking in time you will be fine. If you can't begin to deploy your brakes within two seconds of something happening to the vehicle in front you are simply not observing correctly.

Ah, superb, 'if you can't deploy the brakes within 2 seconds' but you have only allowed 2 seconds between the car in front remember, the 2 seconds in which you deploy is the thinking distance, this is added to the stopping distance, so at 7 seconds you have 2 seconds to think and 5 seconds to actually bring the car to a halt. Looking in those terms it isn't that much time actually.

I realise that very rarely is the vehicle in front going to come to an immediate dead stop, what I'm talking about here is the difference between just about managing to survive if you've been very lucky, compared to surviving with a fairly comfortable margin.

Name one single scenario where the vehicle in front will come to a complete and total stop...

Your distance is not comfortable, it is excessive by a long margin.

[25NAD90TUL]

109er said:

I'm thinking of putting a sign on the back of mine with the following wording:

The gap in front of this vehicle is its safe stopping distance.
If you must enter it, be prepared to be mounted from the rear.

LOL, I imagine you have to regularly mop the axle oil out of the drums, especially at MoT time. hey good to meet a fellow LR man, my name is my main driver 1986 army Truck Utility Light, that's a coil-sprung Ninety, not a defender, as you know. I have quite a few landys.

[25NAD90TUL]

0000 said:

Look closer. The line above the last one is the Highway Code's. The last line is an additional comparison to show how yours compares, not the Highway Code's.

Thank god for that, wondered what was on there, I'd need a microscope to read it, the text is so small. Ok that's clarified, yes I'd prefer an empty lane.

Thanks for making that diagram, I'm going to download that!

[25NAD90TUL]

I've messed up badly in this thread, I have stated that 215 metres at 70 is the stopping distance according to the Highway Code, IT ISN'T.

I got it wrong as I didn't realise that diagram on page 2 had been added to with the distance I am recommending.

I don't have those figures committed to memory, I view my safe gap in terms of seconds and gauge it by watching the vehicle ahead as it passes a landmark, I then count the seconds until I pass same landmark.

This is not a retraction on what I have said regarding the 7 second gap. Just that I got confused over the actual distance quoted in HC.

I should also state that on the M5 most of the time you can have whatever gap you want, it's mostly empty. And that on the M6 it's often so clogged Northbound from the M5 intersection that 70 is rarely possible anyway.

I would also add that reaction times can't be that fast in this thread. You missed an opportunity there to slate me to death and get me all muddled!

My 7 second gap at 70 hasn't changed!

[109er]

25NAD90TUL said:

LOL, I imagine you have to regularly mop the axle oil out of the drums, especially at MoT time. hey good to meet a fellow LR man, my name is my main driver 1986 army Truck Utility Light, that's a coil-sprung Ninety, not a defender, as you know. I have quite a few landys.

Not yet I haven't. The seals are OK at the moment. A rebuild is in the offing and I intend to change
the seals and the 'lands' they run on during the rebuild. Well I say rebuild, it will in fact be a rolling
restoration job until it gets round to the chassis ( Richards replica galvi job) and engine recon using
my own engine (Turners job) Its going to cost a few bob (about £7000) but it will be worth it for a
vehicle that will last another 40 + years. Remember, its 54 years old this year and is still running on
all of its original running gear. All of the serial numbers on all of the parts all match to 1960.

My one is a 1960 Series 2 109" Station Wagon. It's number 92 off the production line for 1960.
They only made 101 that year. In total from 1959 to 1961 they only made 342 for the home market.
Makes it a bit rare in the Land Rover community.

[25NAD90TUL]

WinstonWolf said:

Name one single scenario where the vehicle in front will come to a complete and total stop...

Your distance is not comfortable, it is excessive by a long margin.

Scenario, how about when the car ahead rear ends the tail end Charlie of a pile up, for example that bonfire incident last year.

Edited to add, where people's forward obs and stopping/following distances were, surprise surprise, woefully inadequate.

Edited by 25NAD90TUL on Monday 13th January 17:31

[25NAD90TUL]

109er said:

Not yet I haven't. The seals are OK at the moment. A rebuild is in the offing and I intend to change
the seals and the 'lands' they run on during the rebuild. Well I say rebuild, it will in fact be a rolling
restoration job until it gets round to the chassis ( Richards replica galvi job) and engine recon using
my own engine (Turners job) Its going to cost a few bob (about £7000) but it will be worth it for a
vehicle that will last another 40 + years. Remember, its 54 years old this year and is still running on
all of its original running gear. All of the serial numbers on all of the parts all match to 1960.

My one is a 1960 Series 2 109" Station Wagon. It's number 92 off the production line for 1960.
They only made 101 that year. In total from 1959 to 1961 they only made 342 for the home market.
Makes it a bit rare in the Land Rover community.

Very nice!

[25NAD90TUL]

M5 Taunton 2011, seven people dead and fifty one injured. Some people avoided the carnage completely, some sadly were in the thick of it, yes if you hit a lorry that has stopped in a pile up it is stopped, you aren't going to move it. It is stopped dead.

[WinstonWolf]

25NAD90TUL said:

WinstonWolf said:

Name one single scenario where the vehicle in front will come to a complete and total stop...

Your distance is not comfortable, it is excessive by a long margin.

Scenario, how about when the car ahead rear ends the tail end Charlie of a pile up, for example that bonfire incident last year.

Edited to add, where people's forward obs and stopping/following distances were, surprise surprise, woefully inadequate.

Edited by 25NAD90TUL on Monday 13th January 17:31

Which is why I say observation is more important. Seven seconds wouldn't have saved you there as you'd have still piled in, just later.

Another example of seven seconds at seventy MPH, that is almost fifty four car lengths...

[25NAD90TUL]

A lot of this boils down to experiences you have or haven't had. I'm not going into details, that would be too traumatic. Suffice to say I did 24 hour accident recovery for a few years in the late eighties early nineties. Some of the things you have to deal with make you think about stopping distances and safety margins.

Mine might be excessive in your eyes, to others it might not be.

[SK425]

25NAD90TUL said:

Scenario, how about when the car ahead rear ends the tail end Charlie of a pile up, for example that bonfire incident last year.

I don't know about anyone else, but if I'm following someone at about 2 seconds at 70mph, it's on the basis that I can see what's going on up ahead and I'm going to get a hell of a lot more than 2 seconds notice - a hell of a lot more than 7 seconds notice for that matter - of something like a pile up ahead. If your main or only source of information is the vehicle immediately in front of you then following as close as 2 seconds is rather bold, but there's usually loads more information available than that.

If I can't see far enough ahead for some reason - e.g. following a large vehicle, or driving through fog or smoke - I'd increase my following distance, but I don't generally feel the need to use a following distance suitable for poor visibility when visibility isn't poor. In normal conditions I've never found a two second gap - or maybe even a bit less - has made it difficult to deal with encountering stationary traffic ahead.

[25NAD90TUL]

WinstonWolf said:

Which is why I say observation is more important. Seven seconds wouldn't have saved you there as you'd have still piled in, just later.

I disagree, my forward obs is pretty good on top of my large gap.

[25NAD90TUL]

SK425 said:

I don't know about anyone else, but if I'm following someone at about 2 seconds at 70mph, it's on the basis that I can see what's going on up ahead and I'm going to get a hell of a lot more than 2 seconds notice - a hell of a lot more than 7 seconds notice for that matter - of something like a pile up ahead. If your main or only source of information is the vehicle immediately in front of you then following as close as 2 seconds is rather bold, but there's usually loads more information available than that.

If I can't see far enough ahead for some reason - e.g. following a large vehicle, or driving through fog or smoke - I'd increase my following distance, but I don't generally feel the need to use a following distance suitable for poor visibility when visibility isn't poor. In normal conditions I've never found a two second gap - or maybe even a bit less - has made it difficult to deal with encountering stationary traffic ahead.

So we're assuming now that I leave a 7 second gap but meanwhile I'm looking no further ahead than the car in front's bootlid? C'mon.

[WinstonWolf]

25NAD90TUL said:

WinstonWolf said:

Which is why I say observation is more important. Seven seconds wouldn't have saved you there as you'd have still piled in, just later.

I disagree, my forward obs is pretty good on top of my large gap.

You do realise you're leaving ten times the recommended thinking distance and more than double the complete stopping distance?

I constantly adjust my gap depending on what's happening further up the road. What's happening immediately in front of me is generally less important than the events unfolding further up ahead.

[25NAD90TUL]

Basically folks, do what the hell you want...Just don't try to tell me that what I do is illegal, or slow or anything like that. Don't assume that I don't have excellent forward observation. Also don't get the idea that I'm driving some plastic bumper st that's going to cushion the impact if you rear end me, I might get a bit of whiplash, but will be retaining my ability to stand and walk, I wouldn't have the same hope for the person who rear ends me airbag, crumple zones or no.

My permanent four wheel drive, huge four wheel discs and big grippy tyres may enable me to stop quicker than you might think.

I'm maintaining that 2 seconds at 70 is inadequate, 7 is erring on the safe side, 4 has been suggested which is somewhere near the middle of these two extremes, and has to be well better than 2.