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 Post subject: Speedo: General comments
PostPosted: Tue Apr 13, 2004 17:16 
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This topic relates to Safe Speed Page: "Speedo"

You can view the page here:
http://www.safespeed.org.uk/speedo.html

Related forum topic: Poll:
http://www.safespeed.org.uk/forum/viewtopic.php?t=247

Related forum topic: test results:
http://www.safespeed.org.uk/forum/viewtopic.php?t=254

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PostPosted: Wed Apr 14, 2004 07:16 
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A couple of observations; Firstly, from the point of view of a motorcyclist, the inattention of drivers because they are looking at their speedo is potentially deadly. Here in Australia driver awareness is much worse than in the UK and the added pressure of watching the speedo is making things worse. On Friday I was almost the victim of an inattentive driver who pulled into my lane. With the authorities implying that if you don’t speed you are not a danger all that happens is that they are breeding more and more inattentive drivers with obvious results.

Secondly if the camera is hidden it will actually make the driver even less attentive as they will be concentrating on their speedo more than just in the camera zone.


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PostPosted: Mon Apr 26, 2004 15:11 
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The poll could be accompanied by questions as to how many times and how long the drivers would look at their speedo's in the same scenario; (a) if the camera was not there, (b) if they were driving uphill and (c) if they were driving downhill.

The time spent watching the speedo at each visit could vary to as much a 3 seconds if a driver is trying to maintain their speed within a speed limit on a downhill stretch of road.


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PostPosted: Mon May 16, 2005 11:46 
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In another thread, Rigpig wrote:
The 'Speedo' page on the main SS site offers a compelling argument suggesting that constant speedo checks detract from the time one has to observe the road ahead. Little wonder that this hook has been grasped by so many. Yet I've always thought of it as being a bit of a red herring - an argument based on specious thinking.
Human beings do not, as handy pointed out 'time slice'. We don't view the world as a series of individual images running like a cine film. When we glance down at our speedo (as apart of the normal driving process as opposed to tuning the radio which is entirrely different), we don't throw away a number of frames from the scene ahead and when we look back to the road we don't need to rebuild the scene afresh. It's all part of a smoothly running multi-tasking process which humans are very good at. In fact, it's like the diffrence between AVI and MPEG video encoding if you like.
To suggest that up to 20% of ones time is 'lost' staring at the speedo in the vicinity of a camera is, I therefore propose, misleading in-extremis.


I agree strongly with your main point about the human brain carrying out parallel multitasking. Yes, we are continuously aware of various deveoping circumstances when we drive - we can take account of at least 5 and maybe ten developing hazards.

But the human eye cannot multitask. It's looking in one place at one time and one place only. We have peripheral vision, and certainly gross changes in peripheral attention draw one's attention.

Driving safely depends entirely on the high resolution centre part of one's vision. It's only the high res centre part of our visual field that can pick up the frequent subtle clues to danger ahead. Just think of the shadow behind a parked vehicle or the glint through a hedgerow that we readily accept as a warning of danger.

If we're not looking in the right place we don't get the warning. If we're looking at the speedo, we're not looking in the right place. And when you apply a small drop in attention to the road ahead across a huge population, it will certainly lead to unhealthy coincidences between lost attention and developing hazards.

I do believe that the whole 'speedo' argument is important and significant, and you're right that it's picked upon because it's easily understood and communicated. But it's a very far from our most important arguments. I see it as a bit of a 'loss leader' - we may not 'profit' from it greatly, but it sure gets folk in through the door!

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PostPosted: Mon May 16, 2005 12:15 
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SafeSpeed wrote:
I agree strongly with your main point about the human brain carrying out parallel multitasking. Yes, we are continuously aware of various deveoping circumstances when we drive - we can take account of at least 5 and maybe ten developing hazards.

But the human eye cannot multitask. It's looking in one place at one time and one place only. We have peripheral vision, and certainly gross changes in peripheral attention draw one's attention.

Driving safely depends entirely on the high resolution centre part of one's vision. It's only the high res centre part of our visual field that can pick up the frequent subtle clues to danger ahead. Just think of the shadow behind a parked vehicle or the glint through a hedgerow that we readily accept as a warning of danger.

If we're not looking in the right place we don't get the warning. If we're looking at the speedo, we're not looking in the right place. And when you apply a small drop in attention to the road ahead across a huge population, it will certainly lead to unhealthy coincidences between lost attention and developing hazards.

I do believe that the whole 'speedo' argument is important and significant, and you're right that it's picked upon because it's easily understood and communicated. But it's a very far from our most important arguments. I see it as a bit of a 'loss leader' - we may not 'profit' from it greatly, but it sure gets folk in through the door!


Paul, thank you for your considered response, well reasoned and explained as usual.
Just to pick up on one completely valid point you made, i.e. that one can only look in one place at one time. I agree, but would counter by suggesting that, as per one of the cornerstones of your core argument, when a driver becomes aware of a developing hazard he/she begins to respond to it. I suggest that one of those responses would be to suspend the glances at the speedometer (another being to at least prepare to slow down); thus the 20% loss of time proposed on the speedo page would rapidly reduce if a hazard actually presented itself.


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PostPosted: Mon May 16, 2005 12:46 
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Rigpig wrote:
Just to pick up on one completely valid point you made, i.e. that one can only look in one place at one time. I agree, but would counter by suggesting that, as per one of the cornerstones of your core argument, when a driver becomes aware of a developing hazard he/she begins to respond to it. I suggest that one of those responses would be to suspend the glances at the speedometer (another being to at least prepare to slow down); thus the 20% loss of time proposed on the speedo page would rapidly reduce if a hazard actually presented itself.


That's true except when the hazard in question first presents itself while attention is diverted. Obviously every hazard has a 'moment of first presentation', and the more we take attention away from the road ahead the greater the chance of missing or delaying the first observation.

Sometimes it's possible that a hazard will be visible for a fraction of a second and not visible again until it's too late. The 'glint through a hedgerow' example is like this. Miss the glint and you miss the opportunity to avoid.

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PostPosted: Mon May 16, 2005 13:33 
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Rigpig wrote:
Human beings do not, as handy pointed out 'time slice'. We don't view the world as a series of individual images running like a cine film. ... To suggest that up to 20% of ones time is 'lost' staring at the speedo in the vicinity of a camera is, I therefore propose, misleading in-extremis.


This has often occurred to me to, but zealots cling to this one and I can’t be bothered pointing out their error. But now you’ve raised it, I’ll have a go.

Knowing your speed is a ‘housekeeping’ routine, that you do when times are good, in preparation for times of danger or real threat. Humans, like all species, are adept at applying large amounts of focus when in danger and reducing that for ‘housekeeping’ routines when they judge that there is far less danger. We all know that there are times when we can look at our speedos fairly safely, and at other times it would not be as safe. So you check your speed when you can, and you judge how much it has changed until you check it again.

That is the routine that should be adopted, and it is ironic that the zealots preach that it is ‘too mechanical’ to check your speed from time to time (and to be aware of changes between checks) when this way of doing things is a natural extension of our most basic evolved instincts.

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PostPosted: Mon May 16, 2005 13:44 
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basingwerk wrote:
Rigpig wrote:
Human beings do not, as handy pointed out 'time slice'. We don't view the world as a series of individual images running like a cine film. ... To suggest that up to 20% of ones time is 'lost' staring at the speedo in the vicinity of a camera is, I therefore propose, misleading in-extremis.


This has often occurred to me to, but zealots cling to this one and I can’t be bothered pointing out their error. But now you’ve raised it, I’ll have a go.

Knowing your speed is a ‘housekeeping’ routine, that you do when times are good, in preparation for times of danger or real threat.

Exactly. I couldn't have put it better myself!
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Humans, like all species, are adept at applying large amounts of focus when in danger and reducing that for ‘housekeeping’ routines when they judge that there is far less danger.

nods vigorously...
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We all know that there are times when we can look at our speedos fairly safely, and at other times it would not be as safe.

Right again. This is how we all used to do it.

Exept that now, we have speed cameras which demand an instant check of the speedo, right there and then, and right at an accident "hot spot", ie the sort of location that fits in with your second definition of "at other times it would not be as safe.

Well done BW, that's about as clear an illustration of the "speedo distraction" effect of cameras as we could ever wish for.

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PostPosted: Mon May 16, 2005 14:34 
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Rigpig wrote:
Just to pick up on one completely valid point you made, i.e. that one can only look in one place at one time. I agree, but would counter by suggesting that, as per one of the cornerstones of your core argument, when a driver becomes aware of a developing hazard he/she begins to respond to it. I suggest that one of those responses would be to suspend the glances at the speedometer (another being to at least prepare to slow down); thus the 20% loss of time proposed on the speedo page would rapidly reduce if a hazard actually presented itself.


I completely agree that a driver will naturally suspend a speedo check if a hazard is developing but if the presence of a speed camera tends to make drivers glance at the speedo when they should be (and want to be) giving full attention to the road ahead, then the camera has become an additional hazard, has it not?


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PostPosted: Mon May 16, 2005 15:09 
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JT wrote:
Exept that now, we have speed cameras which demand an instant check of the speedo, right there and then, and right at an accident "hot spot", ie the sort of location that fits in with your second definition of "at other times it would not be as safe.


I know - it's a sort of Heisenberg effect. it could be the case that positive effects outweigh this, but the opposite could be true. Careful though JT - you have raised an argument for concealed cameras!

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PostPosted: Mon May 16, 2005 15:23 
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Observer wrote:
I completely agree that a driver will naturally suspend a speedo check if a hazard is developing but if the presence of a speed camera tends to make drivers glance at the speedo when they should be (and want to be) giving full attention to the road ahead, then the camera has become an additional hazard, has it not?


I don’t see why we should share the road with any driver who is unable to check and judge his speed in a safe and timely manner.

The Heisenberg effect of visible speed cameras could be added to the possible adverse effects, but it would have to be weighed against the positive ones. For example, if (as you say) the driver should be (and wants to be) giving full attention to the road ahead, then that implies that the road ahead has many hazards, in which case they are well advised to reduce speed to the point where they can check their speed safely. Nobody should be driving so close to their limit. But that’s the trouble - many are.

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PostPosted: Mon May 16, 2005 16:07 
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Observer wrote:
I completely agree that a driver will naturally suspend a speedo check if a hazard is developing but if the presence of a speed camera tends to make drivers glance at the speedo when they should be (and want to be) giving full attention to the road ahead, then the camera has become an additional hazard, has it not?


I agree that the presence of a speed camera will give us something extra to consider. Whether this poses an additional hazard is going to depend largely, I suggest, upon ones frame of mind whilst travelling within its zone.
But when we peel away the outer protective layers, this is what lies at the heart of the entire issue isn't it?


Last edited by Rigpig on Mon May 16, 2005 16:10, edited 1 time in total.

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PostPosted: Mon May 16, 2005 16:10 
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basingwerk wrote:
For example, if (as you say) the driver should be (and wants to be) giving full attention to the road ahead, then that implies that the road ahead has many hazards, in which case they are well advised to reduce speed to the point where they can check their speed safely.

This depends on the road, each road will have it's distinct set of hazards. As a driver you have to try to predict all possible hazards even though most of the time they never occur, that requires being aware of what is going on all around.

basingwerk wrote:
Nobody should be driving so close to their limit. But that’s the trouble - many are.

I disagree if this were the case then with 12 million convictions of speeding motorists would suggest that the accident rate should be much higher if this were true. Also eveyone has their own limit my limit will be much different to yours and the more experienced the driver the greater their limitation is, but generally everyone drives within their own abilities.

Speed cameras cannot make the distinction on personal ability nor on the road conditions to which a driver applies their driving ability, setting speed limits alone does not make the road safer, it always boils down to the driver's ability and not speed. For example someone travelling at 35 mph focused on a road and aware of their surroundings will alway be safer than the daydreamer travelling at 20 mph on the same road with their mind in neutral.

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PostPosted: Mon May 16, 2005 16:45 
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basingwerk wrote:
For example, if (as you say) the driver should be (and wants to be) giving full attention to the road ahead, then that implies that the road ahead has many hazards, in which case they are well advised to reduce speed to the point where they can check their speed safely. Nobody should be driving so close to their limit. But that’s the trouble - many are.


We can't tell what the hazard density will be at any particular time so we don't know that the presence of the camera will have a negative effect but there is a risk that it may do. If the camera is located where the probability of a significant hazard is greater, the risk of a negative effect is greater. Saying that drivers would be "well advised to reduce speed" rather misses the point. We can't control a driver's state of mind but we can ensure that we don't add possible distractions to the driving task that are not absolutely necessary, especially in places where it appears likely that hazards will develop frequently.

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Nobody should be driving so close to their limit.


I agree. But how does a driver become aware of his 'limit'. It's not a fixed number is it? He may learn by experience/self-improvement but he would learn sooner and at less risk to others if it is done by educating him.


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PostPosted: Mon May 16, 2005 16:53 
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Rigpig wrote:
But when we peel away the outer protective layers, this is what lies at the heart of the entire issue isn't it?


The distracting potential of speed cameras is not the whole of the argument against them, just one of many which should be considered, at the same time as considering the potential positive effects.


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PostPosted: Mon May 16, 2005 18:09 
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Observer wrote:
Rigpig wrote:
But when we peel away the outer protective layers, this is what lies at the heart of the entire issue isn't it?


The distracting potential of speed cameras is not the whole of the argument against them, just one of many which should be considered, at the same time as considering the potential positive effects.


Agreed. As I said right at the start though, I believe it to be a pudding that has been truly over-egged.


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PostPosted: Mon May 16, 2005 21:35 
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basingwerk wrote:
I don’t see why we should share the road with any driver who is unable to check and judge his speed in a safe and timely manner.


And I don't see why we should share the road with any driver who can't, or won't, judge an appropriate speed for conditions.

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For example, if (as you say) the driver should be (and wants to be) giving full attention to the road ahead, then that implies that the road ahead has many hazards, in which case they are well advised to reduce speed to the point where they can check their speed safely.


What will it take to get through to you that when the road ahead has many hazards you simply cannot afford to check your speedo.
The greater the frequency and intensity of hazards, the less time you have - period.
And when there are no hazards then what your speedo tells you is largely irrelevant.

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PostPosted: Mon May 16, 2005 21:49 
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basingwerk wrote:
I know - it's a sort of Heisenberg effect. it could be the case that positive effects outweigh this, but the opposite could be true. Careful though JT - you have raised an argument for concealed cameras!


What makes you think that concealed cameras are any less distracting?
Do you not think that drivers will devote even more of their attention to their speedos if they don't know where the cameras are? And divert more of their attention to looking for speed limit signs which they may have missed? And, even worse, scan the countryside for the slightest tell-tale sign of a hidden camera?

That's the biggest problem with over-zealous speed limit enforcement - it focuses drivers minds on a numerical speed - which is largely irrelevant.
Especially when the speed limit is set well below what a drivers experience and instincts tells them is the 'natural' speed for the road in question.

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PostPosted: Tue May 17, 2005 11:59 
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Observer wrote:
Rigpig wrote:
But when we peel away the outer protective layers, this is what lies at the heart of the entire issue isn't it?


The distracting potential of speed cameras is not the whole of the argument against them, just one of many which should be considered, at the same time as considering the potential positive effects.


I agree. The greatest argument against them IMO is the infringement of civil liberties

To err is to be human (unless you are driving a car).

Andy


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PostPosted: Tue May 17, 2005 16:43 
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Andy L wrote:
basingwerk wrote:
Nobody should be driving so close to their limit. But that’s the trouble - many are.

I disagree if this were the case then with 12 million convictions of speeding motorists would suggest that the accident rate should be much higher if this were true.


No, I'm sorry but around 10 people have died in RTA's and many times more seriously hurt since your wrote that response, so the accident rate is already much higher than it could be. Complacency is NOT an option. If we had landmines that maimed or killed 1000s of parents and children each week, so that things were as bad as Ulster was or Iraq is, we’d all be up in arms, and quite right! But cars are worse than that!

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