Safe Speed Forums

If they haven't moved over for the past 5 miles they're unlikely to now.

Not only that but the type of "mirror blind" driver who's likely to pull in from L2 to L1 without checking their nearside mirror is the same type of person who will pull out from L2 to L3 without checking their mirror.

When you're 2-3 car lengths from them.

Travelling at 90mph+.

You're in L3 overtaking, and the middle-laner you're overtaking chooses NOW to pull out without looking - you've got nowhere to go, *crunch*.

Or - you're in L1 undertaking the middle-laner and now they choose to pull in without looking. Oh look, you've got a "safe zone"; you can drive onto the hard shoulder to avoid a collision.

Important note here - I'm NOT advocating undertaking on the hard shoulder for one moment, I'm simply saying that if someone cuts in front of you leaving you no space in L1 you can use the hard shoulder to avoid a collision. I spell this out simply because an argument developed on another forum I use because someone interpreted my comment as being in favour of undertaking someone on the hard shoulder - which clearly is not the case!

I never undertake a middle-laner:

- When I'm approaching a junction. MLM (or L3 shareholder) is likely to do a "death swoop" when they realise they're about to miss their exit.

- When there's anything on the hard shoulder, a broken down car etc. Doing this would leave me with no "escape route" should MLM pick now to pull in without looking.

I've never actually had to drive onto the hard shoulder as I described - and I've never actually had anyone pull back in without warning. But whenever I pass nearside I'm always aware that "it could happen" and plan ahead in case it does.

When undertaking a solitary MLM I tend to give a half-second flash on the headlights as I approach to alert them to my presence. Obviously with a string of traffic in L2 and L3 you'd be on full beam all the time!

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Magistrates rule #1: "Never let justice get in the way of a conviction."

lets play with some numbers.

say MLM is doing as stated.... something like 60mph
we're passing at "90+" thats a differential speed of 30mph.

and go with the best case of them pulling across3 car lengths ahead... ~ 12m

you have less than a second to react to avoid impact... lets lose 200ms of that to reaction time and i wont even think about lag in steering vehicle response.

you now have to shift into the hard shoulder across say a typical lane width of 4.5m in the remaining 0.8s

assuming you dont want to crash off the other side of the hard shoulder you probably dont want to be going sideways when you get there.
i make that a lane change manouvre requiring nearly 3g lateral

rather you than me.

i don't think you'll miss the car.. or if you do, at 90mph i don't think you'd collect it up again afterwards.

if you could instantly acheive 1g lateral you might make 3m by the time you arrived at the car but you'd have a fair bit of lateral velocity to scrub off.

i'd consider braking but even then you've gotta manage 1.6g to match speeds.

brown trousers time either way.

Of course with all the driver aids on a modern car it almost makes it too easy. ABS, stability control etc. And one thing I've noticed with a 4WD car is that a sudden change of direction upsets it far less than a FWD or even a RWD.

I remember practising in an empty (private!) car park with the A4 Quattro, sudden turns at high speed etc, lock to lock with full power on in 2nd or 3rd etc. Even with the ESP turned off getting the car to break away is very difficult. Yes, you can provoke it into a tail slide with the ESP off - but you do have to seriously push it. (Note that none of these tests were carried out on a public highway!)

Of course I don't think for one moment that the car is invincible. The moment you start thinking that is the moment you have a big accident. But I know its capabilities, both on the road and on a track.

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Magistrates rule #1: "Never let justice get in the way of a conviction."

Oh well, that makes it OK then...

Passing ANYTHING with a differential speed of 30mph+ is a bad idea, to the left OR the right. The difference is, people EXPECT you to be passing on their right and so are likely to be more mindful. Passing to the left is unexpected and so the MLM is less likely to look properly before making a lane change.

TBH I don't have a problem with overtaking a queue of slower moving traffic on the left, but at the sort of speeds you're discribing I would consider it at best wreckless and at worst bloody dangerous.

Did you also consider the condition of the road surface and the amount of debris that tends to collect on the hard shoulder? What happens when you make your emergency 'swoop' onto the shoulder and suddenly suffer a blow-out as a result of a piece of metal that was too small for you to see in time?

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Science won over religion when they started installing lightning rods on churches.

ABS wont make you stop any faster (in fact if you're as good as you make out it may be worse )

ESP can be quite impressive and I expect you'd be heavily reliant on it in the situation you hypothesise.



90mph +, emergency manouvre... i think you'd be (unpleasantly) surprised.

No - but what it will do is allow you to keep steering whilst braking.

Without ABS any steering with emergency braking will probably result in a spin (unless you can keep a really cool head and cadence brake).



It is - when doing those tests in that private car park I couldn't get the car to "break loose" at all without turning the ESP off. Even with full lock and full power in 2nd-3rd it wouldn't go - the ESP would kick in and correct it.

Turning the ESP off made things a little more interesting, you could get the back end to twitch and slide a little but the Torsen would always pull it back in line.



Which is why I always observe and anticipate before undertaking anyone! Also the half-second headlamp flash before undertaking a lone MLM...

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Magistrates rule #1: "Never let justice get in the way of a conviction."

Umm, have you taken into account the time taken by the MLM to complete their lane change? It looks to me as if your figures are based around swerving to avoid a sudden blockage in the lane ahead, as opposed to reacting to the first twitch left from the MLM. Also you'd need to take the typical motorway lane width and the widths of both the MLMs and Squirrels vehicles, and their starting positions across their respective lanes, into account to decide exactly how far across Squirrel would actually need to move, and how long they'd have to do it.

I'm not condoning passing at 30+ mph without at least one clear lane of separation, neither do I want to see Squirrel unduly criticised on the basis of figures that seem to imply a worse-than-worst-case scenario.

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Chris

Just wait til the MLM wakes up and swerves left to block you....


Don't do it. it's not big and not clever.

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Smokebelching,CO2 making,child murdering planet raping,granny mugging,politically incorrect globally warming (or is it climate changing now it's getting colder?)thug.
That's what the government want you to believe of me. If they get back in I'm emigrating.

What complete rubbish,

the whole thread.

Its simple, keep left unless overtaking

anything else is rubbish[/u][/b]

I'm not sure anyone's learned anything much in this discussion apart from you. (and I'm impressed that you've learned!)

Until people realise that you're just as likely to come across an inattentive, agressive idiot who either views his car as an extension of his manhood or as something that travels to the shops and back on autopillock then crashes will happen and people wll die. It's all very well getting analytical about driving style, but there IS ONLY ONE WAY TO DO IT.
Car drivers don't expect to be undertaken. Therefore DON'T.According to the stats far more KSIs have been caused by people not looking where they are going than anything else. Does that tell people something? Like, driving where you know there's far less chance that an inattentive driver is looking is a REALLY STUPID THING TO DO.

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Smokebelching,CO2 making,child murdering planet raping,granny mugging,politically incorrect globally warming (or is it climate changing now it's getting colder?)thug.
That's what the government want you to believe of me. If they get back in I'm emigrating.

Git You just summed my last post up in 4 words and beat me to it while I was making it.

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Smokebelching,CO2 making,child murdering planet raping,granny mugging,politically incorrect globally warming (or is it climate changing now it's getting colder?)thug.
That's what the government want you to believe of me. If they get back in I'm emigrating.

no.... they dont at all.. they are indeed worst case.
but even if they're a significant factor off target it's not promising!

strictly speaking without ABS any steering will have bugger all effect as the front wheels are likely to be locked !

Civil Engineer,

So the way that 66% of the motoring public choose to drive on motorways is rubbish?

Maybe, but they still do it. Understanding why they do it is not a waste of time.

C.

Thanks Nos.

C.

No it isn't a waste of time at all.

I tend to be a little harsher in my assessment of the average driver than others around here, but IMHO the safety record of Britain's motorways is achieved 'in spite of' rather than 'because of' the way the public chooses to drive on them.

I am constantly amazed at how willing drivers are to leave themselves absolutely no margin for maneouvre at all if things go wrong. They drive periliously close to other vehicles, squeeze between small gaps, have little or no appreciation for the capabilities of other vehicle groups or the needs of other road users, dive headlong into developing situations because they aren't looking far enough ahead, lunge across lanes for the off and on ramps and, of course, demonstrate appaling lane discipline.

I drive about 8 miles to work along a motorway and witness most of the above each and every time.

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Political Correctness is a doctrine, fostered by a delusional, illogical, liberal minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

They're worse than that, you seem to have assumed that the MLM's car will appear suddenly in front of Squirrel, whereas in reality the nut-gathering one will be given some additional reaction time whilst the MLM is moving across the lane markings into L1 and the 2m or so of lateral buffer zone Squirrel ought to have given themselves by positioning their own car as far over to the left of L1 as possible. So rather than having to move laterally by 4.5m (and unless the MLM is driving a wide vehicle, you don't even need to move across that much to avoid a collision) in the 800ms you've allowed, Squirrel only needs to move laterally at least as far as the MLM's vehicle has moved in the same time.



True, like I said before I'm not condoning it, but in reality it is likely to be significantly less dangerous. Still a bit of a crazy thing to be doing, but more likely to result in just a few pints of ice cold adrenaline being dumped into into your veins, rather than being the bowel-cleansing experience you suggested earlier

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Chris

I must agree with your perception here - that makes understanding why the motorways have fewer accidents even more important?

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I won't slave for beggar's pay,
likewise gold and jewels,
but I would slave to learn the way
to sink your ship of fools

Simple. Everyone is moving 'en bloc'.

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Smokebelching,CO2 making,child murdering planet raping,granny mugging,politically incorrect globally warming (or is it climate changing now it's getting colder?)thug.
That's what the government want you to believe of me. If they get back in I'm emigrating.

Yes