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1 mph over the limit?

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1 mph over the limit?

Old 3rd Feb 2018, 09:17
  #21 (permalink)  
 
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I normally maintain betweem 25 and 30 mph in a 30 mph area.Schools 20mph regardless. However when i get anywhere near below the speed limit I am normally tailgated. By a driver, in a German manufactured car, mostly.

Vp Flying without reference to ASI? Oh I've done that before don't worry about that. In an earlier career 45 years ago, part of the training was you learnt to fly the aircraft (powered) with the ASI hidden from you, the handling pilot. Low level, VFR. So I do have some idea what im on about a far as speed by feel, maintance is concerned.

Last edited by Dan_Brown; 3rd Feb 2018 at 10:14.
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Old 3rd Feb 2018, 09:28
  #22 (permalink)  
 
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Originally Posted by chuks View Post
Sallyann, I do get my opinions from the Daily Mail. You have a problem with that, or what?
It's not my problem.
Go for it.
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Old 3rd Feb 2018, 09:31
  #23 (permalink)  
 
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I don't know one front line PC who supports Bangham's proposal and if you look at the Police Oracle news website you'll see that his idea was slagged off by everyone who commented on the story. PO then ran a follow up story which also criticised the proposal.

Bangham's premise is that the law is the law and that it doesn't take very long to write a ticket for a speeding offence. This however ignores two truths. First police 'ignore' or use their discretion in a wide range of situations which often helps to diffuse situations and lets PCs come across as human and reasonable. Removing that discretion would therefore be counter productive and would alienate a vast swathe of people who may have made a genuine mistake with their speed. It would also be hypercritical of us if we enforced the law to the nth degree for speeding but didn't take the same approach to shop lifting for example. In addition there are so few traffic and response PCs around nowadays that they don't have the time to write tickets. In my force traffic cops stop work at 0200 with firearms taking over traffic duties on the motorway. I think that what few traffic officers which are left should concentrate of poor driving standards and not on people driving just a few MPH over the speed limit. Tailgating, drink driving, mobile phone use, jumping red lights etc is far more dangerous than 1 mph over the limit.
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Old 3rd Feb 2018, 09:51
  #24 (permalink)  
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This should go down well with those who feel the RTA doesn't apply to them......and that drivers are being "persecuted " as they are wont to say.

https://www.derbyshiretimes.co.uk/ne...imit-1-8998846

A suitably attention grabbing headline, but, when you read the story, she has nobody but herself to blame.
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Old 3rd Feb 2018, 10:08
  #25 (permalink)  
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Many years ago, I was driving my 'souped up' saloon in my university town when I stopped at traffic lights.
A chancer stopped alongside me, so, when the lights went green I gave it as much as I could but lost out initially to my challenger, but managed to pass him as he slowed - before being waved-down by a policeman.
"And how fast do you think you were going?"
"Oh, second gear, 30 mph . . ."
"Come come, sir. The car that you overtook went through the radar beam at 40 mph. Unfortunately that doesn't prove that you were going faster than that, however, we have got our eye on you and will be looking out for you!"
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Old 3rd Feb 2018, 10:37
  #26 (permalink)  
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Originally Posted by VP959 View Post

Ever flown a glider? If you have you will know full well that it's second nature to hold best glide speed within about +/- 1kt without looking down at the ASI. In fact looking at the ASI is a near-certain recipe for drifting away from the desired speed very quickly.
Erm yes, "once or twice " and nobody I know can claim to fly to + / - 1kt accuracy.....in still air, possibly with the trim set because I encountered this once between Eindhoven and Weert ( before landing in a field adjacent to a quaintly named establishment "Chateaux de Sade ") , but certainly not when in a lumpy thermal, in wave rotor or a near limits cross wind approach . And if you don't monitor the ASI, that's a very good recipe for suddenly finding out the hard way how spins and stalls occur.

Last edited by Krystal n chips; 3rd Feb 2018 at 16:08.
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Old 3rd Feb 2018, 10:40
  #27 (permalink)  
 
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Personally, I can't really see a problem with the current policy at motorway speeds, as the risks are demonstrably low (motorways and dual carriageways are pretty safe compared to other roads, IIRC).

The real issue is in urban areas, in 20mph, 30mph or perhaps even 40mph, limits, where a small increase in speed has a disproportionate effect on the outcome of an accident, particularly when it comes to accidents involving pedestrians or cyclists.

I can't really see this being a major issue for the police, as speeding offences in these areas seem to be primarily caught by cameras.

So why not have a sensible compromise. Allow the police to use judgement in the way that skydiver69 mentions above, but remove the +10% allowance from all urban speed cameras?

From most of the stuff I've read the main issue with the majority of drivers who drive too fast seems to be in urban areas, anyway. The ones that hit the headlines are the very tiny minority who drive at silly speeds on open roads, but that doesn't necessarily mean they pose the greatest risk.
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Old 3rd Feb 2018, 11:02
  #28 (permalink)  
 
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Originally Posted by Gertrude the Wombat View Post
Not me, it's a fraction of a second to flick the cruise control on, job done.
It's not always practical to drive on cruise control, though. I generally have mine switched on all the time and it works well when cruising on a motorway or dual carriageway. But my cruise control disengages the moment I brake or change gear, and since this happens frequently on busy or windy single carriageway roads it's just not worthwhile re-engaging it.

While I generally agree, though, that with sat-nav and other systems built into modern cars there are less excuses to be unaware of the speed limit, sometimes even drivers with the best of intentions may drift slightly over the limit. What worries me about these proposals is that they could remove any discretion traffic police have for dealing with very minor transgressions.

Am I the only person to suspect that in recent years a new generation of senior police officers have come to prominence who seem to have a worrying appetite for criminalising as many people as possible? Not just on the roads, but generally - obviously the recent rape trials come to mind.......
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Old 3rd Feb 2018, 11:13
  #29 (permalink)  
 
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My car has cruise and speed limiter
Cruise for dual carriageways and Motorways, Speed limiter for any area 20-30-40-50 mph etc so I cant accidentally speed

Gives the Police more time to catch real criminals
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Old 3rd Feb 2018, 11:17
  #30 (permalink)  
 
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"UK police chief want to prosecute drivers going 1 mph over the limit".
Non-story.
Nothing to see here.
Move along.
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Old 3rd Feb 2018, 11:29
  #31 (permalink)  
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Originally Posted by Krystal n chips View Post
https://www.derbyshiretimes.co.uk/ne...imit-1-8998846

A suitably attention grabbing headline, but, when you read the story, she has nobody but herself to blame.
A stupid woman who thought that the law didn't apply to her.
provided she was eligible then in all likelihood she would have been offered a speed awareness course (at a cost of about 80 to 100) or if she had taken the 3 points there would have been a fine of 100.

Instead of either of these two options, she now has 6 points and has to pay 998 and declare this to her insurers for the next 5 years.
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Old 3rd Feb 2018, 11:37
  #32 (permalink)  
 
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Let's forget about the accuracy of the speed measurement in the car for a moment and let's speak about the police radar. How precise can they get? I am certain that any measurement tool must have a certification on the margins of error. It has something to do with instruments itself, geometry of measurement (angles can affect readings and shouldn't exceed 11 I guess), weather etc., not to speak about measuring speed from non stationery police vehicle.

I can imagine that fining 1mph "speeding" could be challenged on the court.

But there is another important thing to consider. I've watched once a TV document about a behavioural test and they studied how draconian rules actually affect safety. And in fact it increased the risks. If drivers knew that they could be fined heavily even for small speed transgression they started to bother too much for their speed. Now guess what! Instead of looking out of the window and trying to spot any danger on the road they checked their speedometer so often that this can be deemed as heavy distraction from driving itself. The test used cameras which detected view of drivers and they calculated how often motorists ceased to watch the road and checked instruments instead. Result? This pattern of driving is actually more dangerous than having few mph too much on the speedometer.
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Old 3rd Feb 2018, 11:45
  #33 (permalink)  
 
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Years ago there was a holdup at Hangers Lane at the junction with the North circular. I was going into London and eventually it was my turn to be released by the traffic lights.

As I accelerated a traffic cop on a motorcycle appeared beside me and starting punching his hand down the road. This I interpreted as an instruction to speed up so I did. He stayed beside me as I went to 35, then to 40 and he dropped behind when I reached 50 to chivvy on the car behind.

Can you imagine that happening nowadays.
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Old 3rd Feb 2018, 12:38
  #34 (permalink)  
 
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I've been behind drivers doing 28/34 mph and as soon as they see a camera slam on the breaks, regardless of traffic behind them. Yes I know one should keep a safe distance behind but it can still be rather off-putting.
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Old 3rd Feb 2018, 12:42
  #35 (permalink)  
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My issue here isn't particularly about the speed (no, it wasn't made up by DM; I read about it on BBC) it's about allocation of resources. On one hand our roads are safer than they have ever been. On the other, many thefts, street crime, criminal damage and "minor" burglaries are simply not investigated at all due to "lack of resources".
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Old 3rd Feb 2018, 12:52
  #36 (permalink)  
 
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Well I have never had a speeding ticket but don't claim to be a particularly good driver: being lucky is better than having skill. I have noticed that I drive at a speed I feel is right for the circumstances and was surprised on checking that this is often less than 30 in town. However where I have trouble is in roads for which the speed limit seems too low, the A6 round here being a case in point for which I think the limit should be 50 not 40, as it used to be. Oddly, that stretch was the second highest grossing speed camera revenue area when the average cameras were installed.
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Old 3rd Feb 2018, 13:00
  #37 (permalink)  
 
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Originally Posted by Pali View Post
Let's forget about the accuracy of the speed measurement in the car for a moment and let's speak about the police radar. How precise can they get? I am certain that any measurement tool must have a certification on the margins of error. It has something to do with instruments itself, geometry of measurement (angles can affect readings and shouldn't exceed 11 I guess), weather etc., not to speak about measuring speed from non stationery police vehicle.

I can imagine that fining 1mph "speeding" could be challenged on the court.

But there is another important thing to consider. I've watched once a TV document about a behavioural test and they studied how draconian rules actually affect safety. And in fact it increased the risks. If drivers knew that they could be fined heavily even for small speed transgression they started to bother too much for their speed. Now guess what! Instead of looking out of the window and trying to spot any danger on the road they checked their speedometer so often that this can be deemed as heavy distraction from driving itself. The test used cameras which detected view of drivers and they calculated how often motorists ceased to watch the road and checked instruments instead. Result? This pattern of driving is actually more dangerous than having few mph too much on the speedometer.
The radar guns with [email protected] finders are better than 1mph in terms of accuracy, apparently, at least that's what I've heard about the training given to our local community speedwatch people.

The speed cameras use a fixed doppler radar, and are probably at least as accurate, probably more accurate, than the hand held guns.

Most of the mobile radar traps I've seen in the past few years haven't been operated by the police, they've been doppler radar units either fitted to a parked van operated by a company contracted to run them, or on a few occasions I've seen them on tripod stands on bridges, I'm not sure if it's the police operating them or not.

Not sure what systems the police use in cars now, probably GPS. I believe the police used to use a specially calibrated speedometer in some cars, that had to have a rolling road check periodically, and I know they've also used the time between two known markers as a mean speed check in the past, with a bit of kit in the car that produced a hard copy print out of mean speed (I learned this from practical experience many years ago). My guess is that they now mainly use the GPS speed displayed on their on-board video as evidence now. We seem to have at least one police officer posting in this thread, so perhaps he/she may know better.
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Old 3rd Feb 2018, 13:13
  #38 (permalink)  
 
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Here is a little tale about PC plod and his speed radar gun.

Two British traffic patrol horifficers from North Berwick were involved in an unusual incident while checking for speeding motorists on the A1 Great Nort h Road . One of the horifficers used a hand-held radar device to check the speed of a vehicle approaching over the crest of a hill, and was surprised when the speed was recorded at over 300 mph. Their radar suddenly stopped working and the constabules were not able to reset it.

Just then a deafening roar over the treetops revealed that the radar had in fact latched on to a RAF Tornado fighter jet which was engaged in a low-flying exercise over the Border district, approaching from the North Sea .

Back at police headquarters the chief constable fired off a stiff complaint to the RAF Liaison office.

Back came the reply in true laconic RAF style:

"Thank you for your message, which allows us to complete the file on this incident. You may be interested to know that the tactical computer in the Tornado had detected the presence of, and subsequently locked onto, your hostile radar equipment and automatically sent a jamming signal back to it. Furthermore, an air-to-ground missile aboard the fully-armed aircraft had also automatically locked onto your equipment. Fortunately the pilot flying the Tornado recognized the situation for what it was, quickly responded to the missile systems alert status, and was able to override the automated defence system before the missile was launched and your hostile radar installation was destroyed.
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Old 3rd Feb 2018, 13:19
  #39 (permalink)  
 
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Ah, that old chestnut again ...

Snopes: Did a hand-held police radar unit almost cause the launching of a missile?
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Old 3rd Feb 2018, 13:53
  #40 (permalink)  
 
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An old 'rule of thumb' is that your measuring equipment should have ten times the accuracy of that which you are trying to measure. That gets you within a 95% certainty. So for 30 mph, you need a measurement accuracy of 0.3 mph for the 95% certainty. To go to smaller measurement uncertainty, you need a much better accuracy and discrimination. The difference between 30 and 31mph is 1.47 ft/sec or about 1.76 inches/sec, so you would need to discriminate to better than say 0.2 inches/sec for 95% certainty. I do wonder what the magistrates would say if a barrister started getting the prosecution to admit that they were only 95% certain that the speed was actually 31mph.

Somehow, I don't think CC Plod has ever done any study of measurement uncertainties - he's probably never even heard of them!
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