Safe Speed Forums

well he did seem the sort of brain dead twat that could do it, he had a GPZ 900 easily capable of those speeds and you could ride the roads like that if you wanted to (long and straight enough).

Well - having (like Winnie the Pooh) thought and thought and thought about this, I offer this.

I started off by thinking in terms of 100% responsibility having to be split between overtaker and overtakee (and Paul was looking to define the point at which responsibility was shared 50:50). Therefore, if overtakee is 60% responsible, overtaker must be 40% responsible.

My suggestion is that the sum of responsibilities is not necessarily 100 percent.

In Paul's illustration, if overtakee pulls out when overtaker is a distance/speed which means it is physically impossible for overtaker to brake and/or take other action to avoid the crash, then overtakee has 100% responsibility. However, if overtaker's speed is excessive in relation to overtakee or he failed to observe and anticipate adequately (and so on) then he is contributorily responsible for the crash. His responsibility is (necessarily) on a scale of 0-100 where 0 means no responsibility (overtakee pulls out more or less at at the instant overtaker arrives) and 100 means maximum responsibility (overtaker fails to take any avoiding action even though there was ample time for him to do so).

So the theoretical maximum responsibility is 200 (although I don't quite see what circumstances could give rise to that).

So, at what speed does overtaker have some responsibility and how quickly does it ramp up so as to equal overtakee's responsibility. Answer to the first part must be any speed in excess of overtakee. There is an inherent risk in overtaking for which the overtaker must have some responsibility. After that? Well I suppose the curve of responsibility against speed differentiall will be a bit 'U' shaped. A low differential will give 'x' responsibility and that will diminsh to a minimum at the optimum speed differential (whatever that is) and rise (rapidly) thereafter.

At what speed differential will responsibility be equal? It's impossible to say. All will depend on the facts and circumstances of the individual case.

What say you?

In each case multiplied by the probability of the overtakee changing lanes? Or will that always produce the same speed differential? Not sure how you're translating "time" to "speed (differential)"

I was going to leap in and impetuously state that obviously the risk of the other vehicle changing lanes remains constant, but actually it doesn't does it?

It would be reasonable to assume that the risk of the other vehicle steering into our path is varied by whether he can see us or not. In other words at the point when we are in his blind spot the risk of him steering into us must increase, though it's difficult to put a number on how much.

So for any given speed we can come up with...

t1 = time exposed to danger on approach
t2 = time exposed to danger whilst passing

But the actual degree of hazard must be something like...

h1 = t1 * r1
h2 = t2 * r2

where r is the percentage risk of them steering towards us.

Now we know from the earlier discussion that t1 goes up with increasing speed, and t2 reduces with increasing speed, so the same applies to h1 and h2, but what if r2 is double the value of r1 (ie the driver is twice as likely to pull out when we are alongside, as we spend some of that time in his blind spot) ?

t1 has to get twice as big as t2 now, in order for the level of hazard h to reach a minima (ie h1 = h2).

So when we factor in driver attention, it may be that the optimum passing speed is higher than would otherwise be the case.

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Actually it's more complex than that isn't it?

It overtakee is checking mirror at (say) 15s intervals and overtaker is coming up at speed differential of (say) 20mph then the probability of overtakee becoming aware of overtaker (and therefore the inverse of the probability of him pulling out) must be greater than if the differential is 50mph.

The maths of that is, frankly, beyond me (or beyond what I want to put into it) but the point is, I think, salient.

Good advice which will help clarify the situation should the overtaker consider it.

But it is not widely used, and therefore does not resolve the problem.

I believe the only solution is to restrict the excessive speeder, because his high closing speed is always likely to cause conflict of purpose and planning between them and other road users.

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Fixed ideas are like cramp, for instance in the foot, yet the best remedy is to step on them.

Ian

I'm with Ian - do the half-lane move quite often if I realise I can back off slightly to let someone into "my" lane rather than squeeze them in behind a slowstard.

Yeah, that's a risk I can feel. When I'm in another driver's rear three quarters blind spot I have a subconscious voice saying:

Let's get out of here!

This sort of feeling is (almost?) physical - a sort of edgyness or discomfort. Anyone else get that?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Yes, I do for sure - but only if, somehow, I've not satisfied myself that I've pre-empted my presence, either with a previous "acidentally delayed" dipping of the lights (at night) or witnessed observation of my presence by the one I'm about to overtake (I know that's not infallible, but it does reassure a little of the blind spot bit).

I think you're taking it too far for a couple of reasons... Firstly the greatest risk comes from another driver who doesn't use his mirror at all. So in some important cases the additional calculations are irrelevant. Another scary group of problems is associated with such things as tyre failure - the L2 vehicle swerves due to a blow out. (This one happened to a friend of mine long ago - he was passing a Transit Luton when the front offside tyre blew.) Mirror checks won't help here either.

I believe that there's an important general calculation which tends to recommend speed differentials of 20 or 25mph, and I think we can say with reasonable certainty that the optimum is between +15 and +30mph in all normal cases.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

If I were you and I saw folk passing with very high speed differentials (and modest lateral separation) I'd be worried. On the other hand, if someone driving at 100 mph in L3 slowed to pass some 50mph traffic in L2 at about 70mph, I wouldn't be worried. If someone at 100mph moved to L3 to pass 50mph traffic in L1 I wouldn't be worried.

It's all about appropriate use of speed.

Some of the folk that really scare me overtake with no speed differential at all and spend a minute alongside another vehicle for nothing. I'd want to give them a talking to.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

OK so let's accept that the optimum speed differential is in the range you state. You haven't responded to my suggestion that responsibilty is not 100% shared between two drivers but the sum of the respective responsibilities of the drivers involved which can vary from 0-100 for each.

This fits rather well with the belief that a driver should "take responsibility for his total situation".

I think there are two distinct aspects of responsibility being discussed here.

Clearly when there's a crash there's a pie chart of responsibility and slices could be apportioned to participants showing their relative contributions to incident causation. This is the model I was using when I talked about 50/50. No pie can be bigger than itself so the slices add up to 100%.

The other definition of responsibility is an aspect of driver quality or driver performance. I'm quite sure it's a useful model for many of the things we talk about, but there are dozens (I guess) of driver quality indicators of which 'responsibility' is just one, albeit an important one. I don't think this measure is directly relevant to the conversation we were having.

Having written those two paragraphs above, it now seems to me that you were muddling up two entirely different things because they share a name. What do you think?

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Yes, absolutely, particularly when I'm on the bike. I want to punch though that point of potentially not being seen ASAP.

Snap!

But along with that the considerate speeder must consider the effect his speed is having on the thought processes of Mr average, or Mr 'Tibmin'. His activity should not cause someone to have to alter course or speed, as you say, but it sometimes does.

The correct execution of the overtaking scenario defined earlier depends on the overtakee booking his rightful place at the appropriate time in lane two to commence his overtake of the wagon. Unfortunately, he often gets intimidated by the approaching speeder which can cause him to miss or mistime the manoeuvre. Consequently his desire to make unfettered progress encourages him to linger more in lane two because it's easier.

If the overtakee had a reasonable period of time to consider and make the overtake past the wagon, which a 15 to 20 mile per hour closing speed would allow, then he would be less inclined to remain in lane two.

The initial impression of fast closing speed is the one which lingers in the mind of the overtakee. as soon as he sees that, his decision making process often goes into meltdown. slowing down of the approaching vehicle then only serves to confuse.



But this hapens routinely and almost by design because of HGV limiters. Their right to maximum legal safe progress on motorways predestines these manoeuvres. If you think it's bad now, wait until 2008!!

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Fixed ideas are like cramp, for instance in the foot, yet the best remedy is to step on them.

Ian

I think this reply is spot-on. On the basis that one shouldn't do anything which causes another road-user to change course or speed, if in lane 1 you should wait even if you have to reduce speed, and if you were the driver in lane 2 you should be prepared for the driver in lane 1 to pull out, possibly without indicating. It's no good saying you were within your rights from a hospital bed!

Is this theory, observation, experience or what?

I can't say I'm aware of the effect from my own experience, but since I treat each motorway overtake as a planned manouver I wouldn't expect to trigger the effect. I 'surf the gaps' in motorway traffic, actively driving from hazard to hazard.

I think I believe that the nervous / underconfident / underskilled motorway drivers aren't really intimidated by others as such - more they are intimidated by their own underconfidence, and (maybe especially) by their own observation and planning failures.

When they say things like: "he was coming up fast and I didn't see him" or "all the fast traffic scares me", surely they are just blaming others for their own lack of skill / confidence etc. Aren't they?

Serious questions Ian - I'm very interested in this.

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Paul Smith
Our scrap speed cameras petition got over 28,000 sigs
The Safe Speed campaign demands a return to intelligent road safety

Let me try putting it another way. What I'm saying is that there is a 'causation pie' and a 'responsibility pie'. Using a simple illustration, if a pedestrian steps in front of a speeding car, that may be 100% of causation but if the car was being driven at a reckless speed, the car driver bears a slice of the responsibility pie.

You were interested in defining "responsible behaviour .. by reference to irresponsible behaviour" so I take it you're more concerned with the responsibility pie than the causation pie.

My suggestion is that the size of the responsibility pie is equal to the sum of the responsibility deficits of the parties involved. So it does not follow that because one party's slice of the causation pie is judged to be X that the other party's slice of the responsibility pie is 1 - X.

You gave the illustration of a vehicle (A) pulling out to overtake a truck ahead in the path of another vehicle (B). I am suggesting that A's responsibilty deficit is measured by the seriousness of that error on a scale of 0-100.

At the same time B was overtaking with a high speed differential and he failed to anticipate that A may decide to pull out to overtake the truck ahead. So B's responsibility deficit is also measured on a scale of 0-100.

You asked where the "point of equal irresponsibility" lies. I say that depends on the size of the pie and, therefore, the size of the responsibility deficits of the parties involved.

Hmmm! Difficult to comment properly as did not see this for myself - both standards of driving as described are worthy of a stop by us. On the one hand - we have burnbanks who needs to work on his observation and mirror work (Had this been a derestricted A/bahn - it is more than likely burnbanks would have been 100% liable in the event of a collision per German law - as it is more than reasonably foreseeable that someone will be "stuerming" up the overtaking lane) - and on the other hand - there is someone exceeding the speed limit by a whopping 25 mph on this particular road.

Which one would I have pulled by choice though - on this evidence as posted? It is a tough one! Both actions were equally dangerous - (and the later action by the original overtaker borders on road rage)

Think I would have been more inclined to have a quiet word with original overtaker as he was driving at a speed which was 25 mph above the speed limit on the road, tailgated and behaved aggressively - and it is reasonably foreseeable that a car will move to overtake at the lower speed limit or be in the outer lane at the lower speed. Given his subsequent action of cutting in and slowing down, followed by the speed up to prevent an overtake or push the driver above the speed limit ... I would take a very dim view of that one.

As for you, burnbanks , - more than likely I would have gone after you as well after dealing with the speeder and lectured him about the use of mirrors - as this highlights a serious flaw in your driving. For all I know - you could display this same very serious weakness on all roads and it needs correcting. Given that you were driving slowly - quite possible I'd have caught you up after dealing witht he other guy - assuming I did not manage to pull you both together. Possible - both of you may have realised you were in trouble and stopped. Sometimes both do - so that they can complain to us about the other guy's bad driving.

Think self and our lads would have radioed through to another officer for help (very possible in our patch as almost all the fleet are patrolling at some point in an average day) as it is not easy to stop both drivers (have managed it once - but both realised they were in the "poo" at the time ) or run the car through a trace and contacted this driver on the basis that the driving was flawed.

But - it's a close call and would really test professional judgement - as both drivers displayed weak driving standards.



Your solicitor for real? He's supposed to be objective and professional - and address the law with a view to securing the best possible outcome for you - regardless of your "alleged guilt." He is certainly not supposed to judge you.

Yes - burnbanks - you would have failed a driving test for woefully indadequate observation skills and mirror use: for all I know your poor observation skills could cause an incident on any road. This is why I would have either stopped you at the time or traced you later - dependent on how I judged the danger of the situation. Would I have charged you with careless driving for this? Not necessarily - the acid lecture would have ensured pedantic use of mirrors thereafter - (been told my acid burns to the bone . )



Hmmm! And Northumbria police took aerial photos to make the apple case stick as the policeman's video tape did not record her careless driving and it boiled down to his word against hers - hence the need for CPS to build the case by proving the road was dangerous for a hand to be off the steering wheel.

Have you leave to appeal and make further investigations into this? As Paul says - deceiving the police and perverting the course of justice are very serious offences .

What was the quality of the evidence agaisnt you? Also - you could consider reporting your solicitor's attitude towards you to the Law Society as well as, from what you post here, it does come across as if he did not try his best for you either.

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It's observation and experience, and talking to a lot of lane two hoggers. Among their feeble excuses about sitting in lane two, many translate by and large to intimidation by the quickly approaching vehicle.

I agree largely that it's lack of confidence and ability. But this is a huge black hole of driver training and attitude development, so the other causes of the problem need to be looked at also.

I deal with it by dealing with both groups, the brain dead lane two hogger and the excessive speeder or the speeder who combines his speed with aggressive, intimidatory behaviour.

Problem is, lane two hoggers don't generally get their case past CPS. An offence of similar (or perhaps less) danger, that of excess speed, could lead to loss of livelihood . How do we balance this?

_________________
Fixed ideas are like cramp, for instance in the foot, yet the best remedy is to step on them.

Ian