Contact Position - 2

[DreadUK]

Sorry, new thread on this one but I think it's an important enough point to warrant a bit more examination. And whilst I think there is very little rational reason to adopt a contact position on a motorway, I think there are circumstances on B roads where it is warranted.

What is 'the contact point' At 60mph the stopping distance is 73 metres so (splitting hairs here) if you start your overtake at 73 metres, is that considered the contact position, or is it 1 metre from the car in front.

If you are driving a Porsche or Yam R1 it's hardly relevant, you are simply in the right gear and 73 metres is gone in the blink of an eye, but if you are driving something more modest, 73 metres may make the difference between making a safe overtake or just not bothering.

In my opinion, the stopping distance of both the target vehicle and your vehicle is the same, namely, 55 metres. So assuming you both spot a tree in the road at the same time, both cars should stop safely no matter what their following distance is. Fine in theory, but I'm not prepared to sit 1 metre from anyones bumper however, in anticipating an overtake, I don't think it's unreasonable to move up to within 18 Metres, or slightly more, immediately before the pass is made, and I emphasise, immediately before, and not in a headlong rush at 90mph expecting the overtake.

My justification is that as the overtaking driver you should be at least as alert to the possibilities and circumstances as the driver of the target vehicle, you have allowed adequate thinking distance and are actively looking ahead of the target vehicle so the few seconds exposure to the unlikely event of the driver ahead slamming on his brakes for no apparent reason is minimal.

Again, if you are approaching the car in front at 90mph you are asking for trouble, but a measured gradual approach coinciding with a view opening up in front of you is unlikely to cause much alarm.

But it is down to personal preference, confidence and the vehicle you are in, or on. I don't think there is a 100% right or wrong answer, more it is down to circumstances than technique and providing it looked safe and planned by, say, a following traffic cop, I don't think there is any problem with a contact position overtake under the right circumstances.

[7db]

DreadUK said:

In my opinion, the stopping distance of both the target vehicle and your vehicle is the same, namely, 55 metres.

Assuming:-
- your speeds are the same
- you commit equally to the stop
- you react as quickly as each other to the same stimulus at the same threshold

You're committed to an overtake at the point where you cannot stop behind the other vehicle if he unexpectedly brakes hard.

[DreadUK]

7db said:

Assuming:-
- your speeds are the same
- you commit equally to the stop
- you react as quickly as each other to the same stimulus at the same threshold

You're committed to an overtake at the point where you cannot stop behind the other vehicle if he unexpectedly brakes hard.

- Your speed is unlikely to be the same. You shouldn't be lingering behind the target vehicle but anticipating an opportunity from observations, closing the gap for the overtake, which can be aborted, ideally, with no more than a lift.

- If there's a tree in the road, I would be at least as committed as the other driver to stopping.

- If your observations are effective, you are likely to spot any hinderance to the overtake, if not before, almost certainly at the same time as the driver in front who is probably looking no further than you are, and likely not nearly as far.

In 45 years of driving I have never had a driver brake 'unexpectadly' in front of me when I was going for an overtake. If there is no reason for it, it is as unlikely an event as the cars engine blowing up. If you take that stance on overtaking then you would never, ever go for one.

Whilst nothing is perfect, and no situation the same, please stop dreaming up unlikely scenarios for the sake of bizarre argument.

[SK425]

DreadUK said:

- Your speed is unlikely to be the same. You shouldn't be lingering behind the target vehicle but anticipating an opportunity from observations, closing the gap for the overtake, which can be aborted, ideally, with no more than a lift.

That's interesting. So is the contact position quite a brief transient? (Always thought that was an odd name for it btw - contact is precisely what you want to avoid ). From what I remember of Roadcraft (might have to dust it off an have a look again) you move from the following position (normal 2 seconds or whatever) to the contact position when it looks like an overtake might be on. Then from there the next thing is either back to the following position if the overtake isn't on, or out to the overtaking position for a better look if it seems it probably is on. I appreciate that in the real world every situation is different and what is appropriate this time might not be next time, but I thought the general principle was that the contact position was a position you might hold for a short time - long enough that you would have matched their speed - rather than something you passed through very briefly on your way to the overtaking position. Indeed, I thought the overtaking position could be a position of matched speed as well.

[DreadUK]

Again, it depends on the circumstances at the time. It's not absolutely necessary to approach the contact point,or indeed maintain a following position, then move out for a look before hitting the gas.

If circumstances are favourable, it's not unreasonable to go from a following position directly into the overtake, or indeed from the contact position directly into the overtake.

On a drive you may use different techniques depending on the situation, it's all about flexibility. In my opinion there is no one single correct answer, it might be likened to having an experienced qualified driver like R_U_LOCAL sitting beside you assessing whether you are safe or not. If what you did was safe, and made progress you would likely get the nod.

I was taught on a RoSPA Bike course that the contact position was almost always necessary which was ludicrous as on a 1200 Bandit I could cover the intervening 73 metres from 60 MPH without dropping a gear in seconds. But doing the same thing in my 1.6 Diesel Picasso would barely be possible, even if I was in a lower gear anticipating the opportunity so adopting a contact position momentarily is more appropriate. Lifting off in most diesels in a lower gear gives plenty of engine braking to drop back to following position pretty smartly.

And the expression 'Contact position' is as daft as they get. As you say, it's precisly what you don't want to do!

I also have a real problem with the 2 second rule. We should all have a mental idea of what 23 Metres is, approx. 25% of a football/rugby pitch at 30MPH, 53Metres at 50MPH (approx. double) 73Metres at 60MPH (approx. 3 times) and 96 Metres at 70MPH (approx. 4 times), not difficult. Although I have never bothered to do the maths I believe the 2 second rule is correct once or twice in the stopping distance calculations but I wouldn't argue the point, however, in addition the emphasis is counting lamp posts, bridges, stone walls etc. which is a distraction we don't need.

Edited by DreadUK on Tuesday 20th May 15:09

[DreadUK]

Sorry, not sure I answered your actual question. In my opinion the contact position should ideally be momentary. You should have judged your approach and reached the contact position as the road opens up. You may find the overtake is momentarily not on in which case you may have to hold it for a few seconds, not ideal as you will have lost some impetus, but you can either move out and have a look, continue straight into the overtake or abort with a lift. I think the point is the manoeuvre is done with building momentum that can be arrested if necessary. Like I said, it's not a charge with mad braking if you have to abort.

[SK425]

DreadUK said:

I also have a real problem with the 2 second rule. We should all have a mental idea of what 23 Metres is, approx. 25% of a football/rugby pitch at 30MPH, 53Metres at 50MPH (approx. double) 73Metres at 60MPH (approx. 3 times) and 96 Metres at 70MPH (approx. 4 times), not difficult. Although I have never bothered to do the maths I believe the 2 second rule is correct once or twice in the stopping distance calculations but I wouldn't argue the point, however, in addition the emphasis is counting lamp posts, bridges, stone walls etc. which is a distraction we don't need.

The two second rule is further back than the HC stopping distance (i.e. thinking plus braking) at lower speeds and closer than the HC stopping distance at higher speeds. As it happens, the changeover is at about 40mph, but that's academic and something of a red herring since nobody ever said the objective of the two second rule was to keep you further back than the HC stopping distance.

I'm the other way around to you. I have a problem with specifying the following distance in metres. I don't find that helpful at all. I would find trying to assess the number of metres I am from the vehicle in front or trying to visualise it in proportions of a football pitch or number of double decker buses or something as much more of a distraction than counting "one hippopotamus, two hippopotamus" after the car in front passes a lamp post. I'm much less confident in my ability to assess number of metres than my ability to count hippopotamuses. It's also much easier to have a rule that is independent of speed.

I have the same problem with HC stopping distances. I learnt them for my driving test and I know how to calculate them, but I never use that knowledge for driving.

[7db]

DreadUK said:

- Your speed is unlikely to be the same. You shouldn't be lingering behind the target vehicle but anticipating an opportunity from observations, closing the gap for the overtake, which can be aborted, ideally, with no more than a lift.

This means your stopping distances are different. Worth bearing in mind -- particularly on momentum-style overtakes -- how very very early you are committed to the pass.

DreadUK said:

- If there's a tree in the road, I would be at least as committed as the other driver to stopping.
- If your observations are effective, you are likely to spot any hinderance to the overtake, if not before, almost certainly at the same time as the driver in front who is probably looking no further than you are, and likely not nearly as far.

One of the issues of effective observation is that you might realise that a hazard isn't active before the other driver sees it and panic brakes when he does. Ever had somebody react differently to a hazard than you in 45 years of driving? I'm pretty sure I've seen it in the last 45 minutes of seat-time.

The point about commitment is not that you should avoid it, but that you should realise how early you do it, and do all the things that you might typically imagine doing prior to committing to an overtake before you reach it (such as being in the right place and making a decision about whether to commit).

[DreadUK]

Damn, I must have missed the Hippopotamus's when I was doing my driving courses, never seen one since either!

Again, stopping distances are all approximate anyway, so really whatever works for you. I find it distracting to be continually looking for objects to count from. I simply memorised what 23Metres looks like by pacing it out a few times then practising at 30MPH. after that it's simply a case of doubling up, although at 70MPH 93 Metres just gets filled up with other cars and you feel as though you're going backwards. It also encourages undertaking so I'm inclined to trust my forward observations and cut it down to 70Metres, if not less.

The M25 of course has the magical ability to eliminate the need for stopping distances altogether. The gap in front of you fills up so fast it's often difficult to maintain any meaningful gap regardless of what lane you're in.

[DreadUK]

7db said:

DreadUK said:

- Your speed is unlikely to be the same. You shouldn't be lingering behind the target vehicle but anticipating an opportunity from observations, closing the gap for the overtake, which can be aborted, ideally, with no more than a lift.

This means your stopping distances are different. Worth bearing in mind -- particularly on momentum-style overtakes -- how very very early you are committed to the pass.

DreadUK said:

- If there's a tree in the road, I would be at least as committed as the other driver to stopping.
- If your observations are effective, you are likely to spot any hinderance to the overtake, if not before, almost certainly at the same time as the driver in front who is probably looking no further than you are, and likely not nearly as far.

One of the issues of effective observation is that you might realise that a hazard isn't active before the other driver sees it and panic brakes when he does. Ever had somebody react differently to a hazard than you in 45 years of driving? I'm pretty sure I've seen it in the last 45 minutes of seat-time.

The point about commitment is not that you should avoid it, but that you should realise how early you do it, and do all the things that you might typically imagine doing prior to committing to an overtake before you reach it (such as being in the right place and making a decision about whether to commit).

Assuming you're not on a mad charge to get past the guy in front, your speed shouldn't be so much different as to make an appreciable difference assuming he slams on his brakes for no apparent reason. You're back to ludicrous scenarios that are rarely going to happen. You simply can't legislate for the bizarre situations you emphasise.

I would be interested to know what a "momentum style overtake" is, never heard of that one before. Nor should you ever be "committed" to a pass until you can see it's as safe as it can reasonably be. Asessing and adopting a favourable position for a pass is not the same as committing to one.

Good grief man, what is it about drivers panic braking when you're lining up a pass that worries you so much? If there is a real threat you would abort the pass by lifting off and if you judged it serious enough that the driver in front might start braking, you would at the very least be covering the brake pedal. Whatever version of a pass you adopt there is always the possibility of a driver in front incorrectly assessing what's going on ahead.

As for your last paragraph, I'll refer you my last but one paragraph.

[SK425]

DreadUK said:

I find it distracting to be continually looking for objects to count from.

True. I would too. I don't do it continually though. The two second rule is just an aid to show you what a sensible distance looks like if you've never seen one before, or to recalibrate yourself once in a while if you feel the need. I don't consciously assess my following distance in metres or hippopotamuses. I just try to follow people with what looks like a sensible gap.

[7db]

DreadUK said:

I would be interested to know what a "momentum style overtake" is, never heard of that one before.

One where you catch and pass the target vehicle in one go without adopting a following position and a traditional triangle overtake. Typically higher differential speeds on approach. From a modelling point of view, it is the opposite of a contact position with matched speeds.

In practice, most overtakes are a blend of the two -- a little bit of closing speed from a little further back -- the exact blend being determined by where the car needs to be positioned to take advantage of the vision.

[DreadUK]

7db said:

One where you catch and pass the target vehicle in one go without adopting a following position and a traditional triangle overtake. Typically higher differential speeds on approach. From a modelling point of view, it is the opposite of a contact position with matched speeds.

In practice, most overtakes are a blend of the two -- a little bit of closing speed from a little further back -- the exact blend being determined by where the car needs to be positioned to take advantage of the vision.

Interesting. Thanks for that.

[R_U_LOCAL]

DreadUK said:

7db said:

One where you catch and pass the target vehicle in one go without adopting a following position and a traditional triangle overtake. Typically higher differential speeds on approach. From a modelling point of view, it is the opposite of a contact position with matched speeds.

In practice, most overtakes are a blend of the two -- a little bit of closing speed from a little further back -- the exact blend being determined by where the car needs to be positioned to take advantage of the vision.

Interesting. Thanks for that.

Otherwise referred to as a "rolling overtake". Not common on today's roads, but very satisfying when they do occasionally present themselves. You're looking for a well sighted road, plenty of "plus speed" over the subject vehicle (I never liked the term "target" vehicle), and a subject vehicle which is displaying a steady and constant course.

Without losing any speed or falling in to any kind of follow, the technique requires a nice, very early move to the offside and no change in your speed throughout the overtake.

Niiiiiice!

[DreadUK]

Yep, recognise the routines well, just never had names for them. Lots of room for those types of overtakes on roads in Scotland.

[DreadUK]

One memorable rolling overtake I had whilst home a number of years ago, on a long fast road with a 40mph or 50mph, almost hairpin, leading onto another long fast straight where I could see for miles. Nothing coming no side roads, driveways etc. and a line of about ten cars ahead doing the obligatory 50mph....this was in the 90's, nicely spaced, obedient drivers so plenty of opportunities for an abort if something untoward happened, which it did.

Half way down the line a car popped out.....for a look, before starting it's own overtake, a Strathclyde Police driving school car no less. Driver seemingly forgot to check his mirrors before having a look. Nor did the instructor notice until I was nearly on them with full beam going. By the time they had sorted themselves out my fun was over and I had to get tangled up with the rest of the queue. Passed them again later in the day 'taking tea' hoping it was one of my old instructors so I could get a bit of slagging in but alas not. They had the decency to look a bit sheepish when they recognised my car though.

[R_U_LOCAL]

Overtaking a line of vehicles with a rolling overtake is possible, but it's not adviseable to do so with too much plus speed due to the possibility of one of the vehicles doing exactly what you describe.

A multiple vehicle overtake shouldn't be treated as one overtake, but as multiple overtakes carried out with one manoeuvre. To explain further, the physical actions you take with the car will seem like one single manoeuvre, but mentally, you should be assessing each vehicle individually, weighing up if one of them is looking like it's possibly going to overtake. Look for closing gaps, small movements sideways and dabs of the brake lights (many people sit too close when looking to overtake).

All these mental processes can be carried out during a rolling overtake, but as I mentioned, your plus speed on the subject vehicles shouldn't be too high, or you won't be able to assess each vehicle individually.

[DreadUK]

My speed was in the 60 - 65ish range with lots of escapes as the cars were well spaced. Mostly Grampa's and families, which brings its own risks, but ironic it was a blasted Police training vehicle that caused the problem.

[R_U_LOCAL]

DreadUK said:

Yep, recognise the routines well, just never had names for them. Lots of room for those types of overtakes on roads in Scotland.

One of the reasons Scotland has been the favourite holiday destination for Mrs L and myself for the past few years.

One of many Reasons I should add. I don't want you to think I choose my holiday destination solely on the availability of overtaking opportunities.

[R_U_LOCAL]

DreadUK said:

My speed was in the 60 - 65ish range with lots of escapes as the cars were well spaced. Mostly Grampa's and families, which brings its own risks, but ironic it was a blasted Police training vehicle that caused the problem.

That's the problem when you let students drive. I loved my time at the driving school, but it was somewhat spoiled at times by the inconvenience of having to let students have a go occasionally.