Overtaking Competencies Analysed

Overtaking Competencies Analyzed

There is an often misrepresented and poorly understood argument concerning what happens when a driver of an overtaking vehicle is relying on speed above their [speed limiter] activation, to complete the manoeuvre promptly and safely.
There have been flawed levels of driver education surrounding this subject:

Following is a detailed and comprehensive 9 page article illustrating the most important aspects; however, to gain a succinct and/or "summarised" outline go to the Main heading "Two Dead after Driver Passes on Yellow Lines".

The Myths and Misconceptions:
Sadly, for the [otherwise] minimisation of high speed crashes, whenever the topic of speed limiters is mooted there are 'myths' & misconceptions that abound concerning the affects it might have on overtaking safely.  Read also: Effects On Drivers' Performance.

Matamata (NZ) - 21 Feb- 2011

It is recognised by many qualified commentators, that driver impatience plays a large part in many of the overtaking scenario incidents - that occur from time to time.  It is likewise recognised that ‘impatience’ also leads to a myriad of other foibles - some of which can be exhibited in the ‘known’ Black-Spot areas - by lesser experienced drivers.

One of these foibles relates to the conclusion by some drivers, of an incorrect supposition that it is ‘correct road-craft’ to use relatively high speeds – more than 25km/h above posted limits - when overtaking. [Read below> Time/Over/The/Line]. Unfortunately for the general safety of all road users, this mistaken assumption has not been addressed, and thus it has taken-on an erroneous rationale or justification that tends to allow or to induce the drivers, to think they are driving (overtaking) safely.

Putting to one side the total illegality of any speed above 115km/h, [New Zealand law] there are TWO main answers to this question - and that need to be addressed in some detail. Firstly, the New Zealand road code states emphatically that a driver must have 100 metres of clear road in front of them, throughout the whole of the manoeuvre.
Therefore, if a driver cannot make the necessary judgment and distance evaluations for this, they are either a potential crash statistic awaiting the inherent and unwanted (overtaking) situation to prevail, or they are using and relying on overtaking speeds that could be as high as 150km/h - in order to have prevented themselves from reducing the 100m. clear road factordown to zero metres
. . .

Presumably, it is this reduction of ‘clear road’ that will have resulted in the [hypothetical] crash; that the question - surrounding a lack of speed - is based on.

If this were the case however, and the driver in this (hypothetical) scenario is at present using speeds as high as 140 to 150km/h - to avoid reducing the clear road factor to a dangerous minimum - then this driver also, is surely a serious crash risk - awaiting the inherent conditions to prevail. 
The erroneous justifications that have pervaded the rationale concerning how much extra speed is needed when overtaking, have thus become overstated. With the greater acceleration capabilities of modern cars, there is even less need for high top-speeds when passing [refer below].
The correct position concerning the competencies involved could be summarized by explaining that many of the drivers, who do crash whilst overtaking, are presumably using brief but aggressive levels of acceleration - up to (sometimes) enormous speeds.

Therefore, if the argument for having limiters regulated to a speed as great as 150km/h was to have any practical merit, [for Australia and NZ] there would have to be some form of sanctioned criteria where it was OK to use such very high speeds. There never has been and never will be.

For Example: By implying that accelerating ‘briefly’ to speeds as high as 150km/h is occasionally OK, some [particularly amongst less experienced] drivers, may receive the wrong impression that provided one is overtaking, using such a high speed is the safest option - when driving over the speed limit and on wrong side of the road.
If this foolish rational is being given any degree of tacit validation, then is it any wonder that from time to time we witness drivers having horrific ‘head-on’ crashes, on relatively straight stretches of road - and in good visibility.

'Time' Over the Line:
Any simple "Time" Test conducted (for best/easiest method, on a passing lane) to establish amount of time elapsed whilst overtaking a large truck-trailer unit, will show that it can be done inside of 12 seconds without exceeding 120km/h. Note; this is assuming the truck is travelling no faster than 95km/h.
NB. Analysis of relevant data recorded by Lay (1991) and Troutbeck (1984) or Fildes&Lee- suggests that a typical passing manoeuvre on a rural road will result in a speed about 13km/h faster than the vehicle being overtaken - resulting a "time factor" of about 12.5 seconds.  This empiricaly relevant data further debunks the irresponsible myth that drivers may need to use much more excessive top speeds.

Plouden & Hillman (1991) also point out that the main effect of a speed limiter is that "the driver of a high pereformance vehilce would no longer perform certain manouvers which they now regard as safe" In planning an overtake they must now take a range of factors into consideration and the potential speed of overtaking is one of these factors.
Analysis of data provided by Lay (1991) and Troutbeck (1984) suggests that currently on rural roads the overtaking vehicle travels about 13km/h faster thatn the one being overtaken...

‘Head-on’ crashes & the kinetic energy aspects involved:
Because “head-on” crashes involve combined speeds, the kinetic energy dissipation is very high. This is why they kill.   Refer also; "Combined Speeds".
It is made abundantly clear through-out all proposals in this website, regarding "sensible" speed limiter implementation, that low threshold activation would have very little effect to this “head-on” kinetic energy factor.
Evidence shows many serious trauma crashes occur when one driver fails to execute an overtaking manoeuvre efficiently.  The road code/s of many Westernized countries state that the act of passing - on the open road - is possibly the most dangerous manoeuvre a driver will embark on.

Therefore,  could  a  reduction  in  top  speed  capability  help  to  reduce  this  risk?

If a decision to overtake is made imprudently, the closing speed of the respective ‘head-to-head’ vehicles will be a contributing factor to a crash - regardless of whether the ‘imprudent’ driver is travelling at 115km/h or 137km/h.
he only aspect that could make a significant difference is that if the overtaking vehicle was restricted to 120km/h, it will crash into the other vehicle with much less kinetic energy.

Question; Are the detractors of Speed limiters - in their haste to argue the need to pass safely and efficiently and purportedly requiring a very high top-speed - attempting to suggest that a high top speed is somehow of greater value than the safety benefits achieved by speed limiter restriction?

Is this where the confusion between power + speed comes in?

As pointed out (albeit briefly) in several other "responsible" websites on this subject, any problems that might arise regarding implementation of top-speed limitation ESL would be totally mitigated by the improvements to road safety.

NB. Speed limiters are in essence ‘rev-limiters’ and thus only impact on top speed. The power factor - i.e. the cars ability to accelerate - to any particular speed - is unaffected and completely independent of this.
Secondly; the (former) question also implies that in order to overtake safely, you will be better equipped if you drive a car that has a high top speed.
Though this (obviously) is partially misrepresenting the basic essence of the road code and driving manners, it is implied in the question.

In respect of 'the system of car control swift acceleration capability can be used to an appropriate level if the circumstances allow. This also means that the generally faster acceleration capability of modern vehicles, requires that there is even less need for a high top speed - when overtaking.  [For explanations on correct usage/protocouls for acceleration; Refer to NZTA Road Code; The System of Vehicle Control.]

Activation 'margin' speed is not legitimised:
It is also feasible to predict that some detractors would argue that an ESL [electronic speed limiter] activation of (say) 120km/h infers that this speed is legitimised - even if only on occasion.
Although totally fallacious, such an argument may be appealing to some, looking for weakness in the initiative.  We emphasize, there would be no argument for legitimising of speed above the posted maximum in this regard however. Traffic enforcement officers have always been enabled with flexible powers of discretion, and thus generally allow a 10km/h or slightly greater, margin. This does not mean that in the absence of relevant situations, that (even) 106.04km/h is in any way legitimised.
In any event, such an angle of argument would be totally fallacious for another reason; being that the same (argument) could be levelled regarding the huge 'range' of car speeds, and the [absolutely excessive] top speeds of many vehicles currently restricted at this point!

Underpinning the above, is that in years past, many drivers would have accomplished safe overtaking manoeuvres, whilst driving the vast array of pathetically underpowered vehicles - that many of ‘those drivers’ were using - only 15 years ago! This refers to a time when the power to weight ratio of the average type motor car was 35% lower [in performance] than it was in 2006.
We only need to look back to 1986 to demonstrate this point.   Refer also: Engine pwr restrictions.

The above point is perhaps illustrated even more succinctly and simply, through the comments of intelligent older drivers, who have asked, "How did our age group manage to conclude all the passing manoeuvres of ‘our time- when we for example, were driving a Morris Oxford?Read Also: What Is A Pwr To Weight Ratio.

The increase in the power to weight ratio [PTW Ratio] of the late model vehicle will allow the vehicle to be accelerated more quickly - from the commencement speed to a higher speed - that will take it past the slower vehicle in a shorter time frame and road space. The rationale being that a shorter time phase may prevent an overtaking driver from having to use excessive and dangerous speeds - of perhaps 150km/h!
E.g. Some might argue that if the overtaking vehicle did not have the fast acceleration capability - that may shorten the length of the manoeuvre - then the vehicle may need to reach very high speeds to effect the same (shortened road space) result - [prudent judgment relating to all factors, being a paramount obligation].

Note; on a closer analysis of this effect, there are several important driver influence scenarios - for the serious road safety advocate to be mindful of:

1 If (as stated) the overtaking vehicle possesses quick acceleration,
then it will be able to accelerate and pass slower vehicles, one at a time -
without using large amounts of roadway length to do so.

[ Most vehicles now have adequate acceleration for such manouvering. Refer: note ( 3).]

2 Conversely, if it did not possess the quick acceleration, then it may
either need to use large amounts of road (bordering on illegal) or use a
higher speed - of perhaps 150km/h - or combine both of these exacerbating elements!

3 When overtaking slower vehicles at highway speeds, it can be very hazardous
to attempt to pass more than two, in the course of ‘one’ manoeuvre.

However, for the driver of a vehicle with quick acceleration as-well-as a high 
top speed, there can be a dangerous kind of inducement or enticement -
the inexperienced,  or  the  ‘risk taking’ driver - to attempt to do this.

It is demonstrated however, that this scenario - of using the available “
excessive speed” - has caused many an inexperienced driver to have an incident whilst overtaking!

With this predictable scenario (of inducement) an ever present prospect [and one that is demonstrated to cause serious head-on crashes] a limiting of the vehicles top speed would - in a worst case scenario -  warn the driver to abort the manoeuvre - before they got to the point of where they were rapidly closing on an oncoming vehicle... perhaps at (an unrestricted) 145km/h, or faster.

It would be far safer for drivers to learn how to best use the ‘acceleration’ of the modern vehicle - up to ESL activation - and in doing so pass no more than two vehicles at a time... and when to choose ‘appropriate’ situations.
This type of ‘responsible’ and efficient use of available performance is the same method of car control that many experienced and/or well trained drivers [such as Law Enforcement Officers ] use - and have been trained to use - when they are overtaking.

It could it be argued that a deficiency, in this particular area of car control experience, is a factor in why some, otherwise law abiding drivers, have been known to have “cross-centre-line” crashes  - on notorious NZ highways such as  S.H.2 and  S.H.27 etcetera, - the 'known black spots.
These generally safety conscious and law abiding drivers may have become victims to a fallacious rationale - which implies that 'on some occasions it is safe to use excessive high speeds?

For example; in respect of the above cited phenomenon, (or esoteric pretext for excessive speed?) it should be remembered that on occasion in years past, some incompetent road safety advisors did in fact appear to suggest, that in some situations, it was safe, to use excessively high speeds?

Question; How many innocent lives have been destroyed as a result of that inept an negligent advice?
The incompetence or condescension displayed by those advisors has been addressed in other articles concerning this subject.  However, could it be that some of these (described) law-abiding drivers who have crashed and become a statistic – on these notorious highway ‘black-spots’ - may have been confused by the incorrect advice... that was alluded to by those former, incompetent, road safety advisers when they appeared on TV?

Contradiction and incompetence example: In regards to any driver training aspect implicated with modern vehicles being capable of much greater acceleration in recent years, the best that some authorities have delivered at time of writing, is to fail to correct the rather absurd and safety contradicting comments, made by a prominent racing driver.
I.e.  On more than one occasion in 2005, that (otherwise respected) racing driver commented - in relation to some multiple fatality crashes that had involved very high speeds and younger drivers- "there should be engine power restrictions for novice drivers. . .?? However, on one hand he endorses the use and ownership [by ordinary citizens] of vehicles with ridiculously high top-speed activations on their speed limiter functions, whilst at the same time he appears to want to have some kind of engine power restriction - for less experience drivers?

Even the most challenged motorist can immediately see that such a suggestion is absurd because all cars are now quite powerful - e.g.“where would the power level restriction be set??” - and a myriad of other engineering dynamical reasons exist as to why it would not be practical.

See Article:Why Engine Power Restrictions Would Not be Practical For CARS”.

Is acceleration a problem?
Many vehicles now have impressive acceleration. This, combined with virtually no restriction on top speeds, might induce a small percentage of inexperienced or manipulatively inept drivers, to (possibly) ‘overdo it - when taking advantage of (this) acceleration + excessive top speed capability - of their vehicle.
As (then) might be the case, these less experienced drivers may suddenly find themselves in an unfamiliar situation where they are driving at 138km/h - [perhaps heeding the inept advice given on New Zealand TV in 1996? and at later times also!] - and they may not have chosen the ideal stretch of road, or surface (of road) to perform this speed on.
Should one of these drivers then panic, they could cause a crash of the very nature we witness from time to time on highway black-spots such as SH2 and SH27 etcetera.  This is one reason why the ‘Overtaking Question’ needs to be addressed in reasonable detail.

Rationale: Sadly, as some of the crashes occurring in association with these (former) descriptions are involving otherwise law abiding, ‘family type’ drivers, could it be that about three seconds before brakes were applied in some of these tragedies, the driver had attained a speed of 145km/h? - (reducing to 118.07km/h on impact, but nonetheless fatal). Perhaps an over-reaction of some kind by the driver?
Could it be, that these (15 percent or so of) drivers were poorly trained to begin with, and thereby, when driving a powerful car, the occasional inducement for an imprudent passing manoeuvre has made them a “statistic in waiting” so to speak - when travelling on these notorious ‘black-spot’ highways?

4 )    The further logic here (concerning above) is that if the overtaking vehicle
is only using a modicum of extra speed, to perform the manoeuvre
- e.g. an additional 19km/h - then there is little likelihood of ‘this’ vehicle
having great difficulty in ‘aborting’ the situation - and repositioning.
Many drivers do this on a not uncommon basis, and without incident.
[NB. Refer again, to note <3]

The ‘question’ relating to the overtaking vehicle becoming “trapped” on the wrong side of the road, would only apply if the driver was - upon the outset - INTENDING to use dangerously high speeds.

[NB. This is likewise endorsed by the Australian Road Safety Org: ANCAP who, after a study into the benefits of top-speed limiters, stated that "There are myths and misunderstandings about the need for reserve power and excessive speed when overtaking. In nearly all circumstances a decision to use excessive speed to overtake greatly increases the risk of a serious crash and it would have been much safer to brake than to accelerate - . . ."]

How much time over the line?
A footnote regarding time and distance:
The amount of TIME required to overtake a large truck and trailer that is travelling at 95km/h, without your vehicle exceeding 120km/h, is about 11 seconds - allowing from initial manoeuvre over the centre line, to when your vehicle crosses back to the correct side.

Extra speed and contigency manoeuvres:
e.g. As well as creating difficulty for any contingency manoeuvre, the use of very high ‘extra’ speed would usually indicate a driver with an impatient attitude, alongside of poor judgement skills, and / or hazard recognition skills.   Refer Also: < www.ancap/-Protocoul-for-speed-limiting devices Page 4 >.

Note; that there is no contradiction here. The detractors argue that points 1 to 3 are endorsing the argument that the vehicle, being restricted to a top speed of ‘say’ 120km/h, logically means that ‘this’ vehicle will take longer to pass another - and therefore spend more time on the wrong side of the road. Whilst this is correct in a purely mathematical sense, it is incorrect when it is correlated to the prudent and acceptable use of the road rules and for example “The System of Car Control”.
The illogical reasoning implied in the detracting argument, also underpins the
element of further ‘crucial’ (i.e. correct) logic  - that is based on the road code
- and that actually applies to such a potentially dangerous situation as overtaking.

For example, the (spuriously) flawed (or selfishly arrogant type) logic exposed in this (former) argument - and by people who say that limitations to 120km/h could be dangerous?? - is further illustrated by another reason. This relates to the ‘propensity’ that many drivers of vehicles [not restricted at this point] may have for using a speed of (say) 145km/h, to overtake. [Refer back to page four; “How Many Innocent Lives have been lost as a result/incorrect advocacy. . .?]
E.g. If those drivers are doing this (speed) - even on ‘rare occasions’ (as they might argue?) - they are placing innocent members of the public in potential danger of an elevated kinetic energy impact.

As already stated, [on a previous page and on page 8] this type of high speed - when combined with any, small, unanticipated ‘situation’ during the course of the manoeuvre - has proved to be the cause of many fatal 'two-vehicle'.
NB. It is not a matter of an experienced driver - knowing when it is safe to use excessive speeds to complete an overtaking manoeuvre . . .
It is the predictability -that from time to time INEXPERIENCED drivers will make fatal calculations -when attempting to use some of the 180km/h speed limiter activation on their vehicle, to complete a manoeuvre.

It may almost be perversely fascinating, for those who have lost loved ones to these very scenarios, to hear that people with supposed expertise and/or relevant automotive qualifications, do not [evidently] understand this elementary and fundamental aspect of road-craft proficiency.

Underpinning the most base rationale concerning any contrived safety aspect, is that there is also a straightforward “trade-off” - concerning any perceived risk potential - and  relates to the fact that any unlikely situations that might arise where the ESL limit did somehow present a hazard [associated with driver incompetence or whatever] - the number of these incidents would be minuscule compared to the numbers of casualties prevented, through the limitation of excessive velocity - and the associated impact energy. Refer also: "Two Dead After Driver Passes on Yellow Lines"

Further Conclusions Regarding Closing Speed Situations:
With regard to the question concerning the possibility of a driver becoming “trapped” as it were, on the wrong side of road with a vehicle closing towards them, we need to bear in mind that this is [evidently] happening already.
For example, many of the serious tragedies that are occurring [involving head-ons] - particularly for instance, on the notorious ‘black-spot’ highway areas - are the result of drivers misjudging the manoeuvre.
A sensible way to address the question would be for a driver to ask of themselves; “Have I ever found myself in this predicament - and what did I do to rectify the situation”?

Upon evaluating this two-pronged question, most competent drivers will realise that it is in fact quite uncomplicated to apply standard road code based practices - to facilitate any required hazard avoidance action - and thereby rectify the situation.  These practices would be; to have properly checked mirrors for correct space before commencing, then, upon realising that a fast vehicle is closing too rapidly to allow 100m. of visibility, braking smoothly and slotting back into the vacated space.  If your speed is only 120km/h this is not difficult.  However, if the vehicle closing too rapidly is doing 135km/h - remembering that unless it, too, is overtaking, it should not be going faster than 105km/h absolute maximum - and because you are one of the incompetent and arrogantly selfish drivers mentioned above, your speed is 140km/h - you MAY indeed experience difficulty braking and re-positioning smoothly!!

[Editors note: The need to provide the "tell them how to suck eggs" type detail given in the above paragraph exemplifies that there may still be too many pathetically incompetent drivers on our roads, and many of them are the same people who attempt to put forward spurious arguments against top-speed regulation.]

Conversely, if a driver was to argue, that because they never make these types of judgment errors, but, (because) some drivers nonetheless do err - and that this lamentable statistic (therefore) suggests that speed limiters might present a problem for ‘those’ drivers - and hence the closing speeds danger aspect could be worsened...?? by having a speed limiter...” - such an argument  would also be contradictory to their main rationale.
That is to conclude - with complete accuracy when based on the prominence of ‘two vehicle’ crash statistics - that one reason why these less competent drivers are becoming a statistic is because they are sometimes attempting the dangerous practice of using very high speeds - to accomplish “what they assume” is a safe overtaking manoeuvre.
For the percentage of drivers that ARE [evidently] having difficulty making correct judgment decisions when overtaking; these drivers would be at less of a disadvantage, if their top speed were restricted.    Refer also: Combined Speeds & Association with ESL Restrictions.

Another way to explain the Myth:
To attempt to argue that top-speed regulation could be dangerouse when overtaking is akin to saying that it could be dangerouse to drive a 1300cc vehicle because you may be overtaking and run out of space!  Do we have to ban all cars that have a PTW Ratio of less that <...?? because they might create a serious crash risk associated with this phenomena?

The first - of several questions to ask someone who puts foward such a notion would be; "what speed/s do you use when you overtake? Are they ever as high as 140km/h?!!

The nuance of following vehicles when overtaking; these detractors will also use the spurios notion that danger could be created by vehicles following closely behind when you may need to abort a manoeuvre.  
The reason that some drivers follow closely behind a vehicle that is overtaking is that "at the present time" they are not restricted and can accelerate to enormous speeds - which they may decide to use briefl
y.  If all cars were restricted to a prescribed (and sensible) speed then these drivers would be aware of such, and not follow closely with the intention of using a short blast of very high speed.

This is no different to the very same "reckless driver" being in a powerfull car one day, and the next day driving another one that is maybe only 1300cc. In such cases the driver is totally aware of the limitations of the vehicle and usually they won't therefore attempt a manoeuvre that otherwise might be viable in there usual car.
There may still be occasional instances when a manoeuvre is aborted late, thus causing inconvenience  for the following vehicle.
However; think of the alternative? At present the very same situations are occurring and the default action is to use a sudden burst of acceleration - up to 150km/h or greater - to create THE SAFETY!!??... that is what these incompetent detractors are suggesting!

We see that with a bit of thought about the dynamics associated with all cars on the road being limited to a prescribed top speed, the notion of it creating some type of recurring danger around the overtaking scenario is nothing but myth.
Oftentimes the easiest way to explain this is to restate an previouse sentence, regarding how is that we managed to tollerate the underpowered cars of the 1980s when these were mixing it on the roads with V8s.

The main answere to the 'detractors' notion is that as a driver, you/we will be totally aware of the fact that we can only achive a speed of 120-124km/h - and hence our manoeuvres will be calculated accordingly - in the same manor as responsible drivers calculate them now.

Lets face it; most drivers know when they are doing 120km/h - and what it is like to drive at that speed. We might even commonly use it when we overtake. What would be dangerous would be if we drove drunk or under the influence of some debilitating narcotic and we made an impriudent decision to use a speed of 145km/h to complete a manoeuvre safely!!

The only aspect that changes is that every driver will fully know the limitations of THEIR [not the vehicle's] driving ability.  I say "their" limitations because with a driver not having to decide whether or not to use some really high speed [briefly] they are free to concentrate on other prudent factors involved - and in a worst case scenario, 124km/h is a much safer speed to abort from than 145km/h.

As stated by many sensible safety advocates in recent years, one of the keys to making driving safer for the impressionable younger driver is to give them the "tools" that take away the (otherwise) influencing factors of peer presure and overt folk-law around motoring.

Examples of this are the night drive curfews, Zero alcohol and prohibitions on passengers.

Perhaps, and in light of this psychology, a useful initiative for minimising IMPRUDENT decisions around overtaking would be to have all cars limited to one top speed - thus allowing the driver to only have to think about the "clear road" factor in terms of calculating it at 120km/h - not something... something... maybe 150km/h - but only briefly sir!!

Other Causes of Head-On Crashes:
Every holiday season, there are a number of fatal crashes involving head-ons.

Sadly, many of these have, as their originating (driver) factor, an imprudent decision to overtake.  With others, the driver factor may merely be drowsiness or distraction, leading to loss of control - perhaps aggravated by something as innocuous as a slowly deflating tyre that has not being noticed.

What is constantly evident however, is that a percentage of drivers are prone to being involved in such incidents – and / or they are lacking certain perception skills, that may come more naturally to other drivers. This problem is one that crosses into the realms of associated psychology, and the various driver-training-aspects that might be needed to improve the ability of these drivers to appraise the necessary focal information.

Whatever the reasons, and whatever forms of training that may be used to improve the statistics for these drivers, it is unequivocal that in the meantime a restriction of their vehicles top speeds would prevent the excessively high kinetic energy impacts. Impacts that are currently accounting for the disproportionate amount of fatalities associated with this area of driver competence.