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#Post#: 32734--------------------------------------------------
Speeding - 30mph zone - NIP
DIR By: yuletwigtool--[
Date: August 8, 2024, 2:13 pm
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Hi,
I just received a NIP for doing 38mph in a 30 zone (infringement
date being 01/08/24). It's the first I've ever received in the
UK over the several decades that I have lived here on and off.
I'm not looking to try to get off the penalty (though I wouldn't
say no to that either) as I accept that I was over the limit,
however I am interested to understand how the protocol for
assessing speed via a mobile speed camera works.
I have been travelling through this village road close to where
I live for the past 13 years and most of the motorbike-cop speed
traps have been visible at the side of the road down one end or
the other of the long, straight section of the road. At one end
the road continues straight in to National Speed Limit
(NSL)(60mph) on exit; there is a slight incline just before the
sign. Usually I apply a bit of acceleration at this part which
is only about 15m or so before the NSL sign. Recently a new
speed-cop had been operating from in front or behind a hedge at
this juncture (depending on your direction of travel) about 8m
before the NSL where there is a small, village hall parking
area. I had spotted him from the opposite direction on a few
occasions (though I'm not travelling everyday through there),
and couple of times in traffic going going out the village hall
end. However, on this day I had been driving along the side of
the road closest to where he would be operating and along
hedgerows and did not see any sign of him or his tripod camera
most of the way until I came level with the village hall where I
had just applied some juice for the incline short of the NSL
sign and suddenly he appeared just metres away tucked in to the
carpark hedge a few meteres in, about 7m opposite the village
hall. I immediately slapped the anchors on as I didn't know how
much my speed may have been over on my gauge as I had only just
applied the accelerator and the needle hadn't stabilised, but I
saw it drop to 25mph, before passing him and hitting the NSL.
I haven't registered as the driver yet, as I will probably get a
speed awareness course offer and my (recently acquired) car
packed in just 2 days ago (with a concentric clutch slave
cylinder giving up) and I had to get it towed home where I'll
need to repair it myself over the coming week or so, and I don't
know when I'll be mobile again to attend such a course so I'm
holding off initially.
Anyway I was wondering about how the speed determination is made
by the camera. Is it an instantaneous read or does there need to
be a continuous read for a time period (like 2 secs) in order to
determine speed and not record spurious variations such as
change in the point of reflection on a car surface that may
occur from movement of the car relative to the measuring beam
that may cause the it to instantly jump in distance measured,
such as from bonnet to bumper - or is this never really a
practical issue, and would an instantaneous reading give a
reliable indicator of speed? If anyone knows that can tell me
how it works?
#Post#: 32735--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: The Rookie
Date: August 8, 2024, 2:23 pm
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The camera records what happens, the attached laser device
measures your speed and that takes about 1/3 of a second from
when the operator pulls the trigger (it doesn’t measure
continuously).
It’s not impossible for it to take an incorrect reading but it
is very very rare, a ‘jump’ won’t cause that as it takes a
stream of continuous range readings in that timeframe and they
need to show a near consistent rate of change of range, a jump
would make that non linear and it’s stated that it would then
display an error code and not a speed.
#Post#: 32799--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: yuletwigtool--[
Date: August 9, 2024, 8:33 am
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Thanks The Rookie, that does at least answer the technical side
of the measurement. Do you know if there needs to be a minimum
distance of straight road in which to take these measurements? -
I had heard some while back that something like 50m of straight
line roadway was required in order to get a head-on reading, but
this may have been for older equipment idk
#Post#: 32805--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: Southpaw82
Date: August 9, 2024, 9:04 am
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If the reading is taken in 1/3rd of a second, why would there
need to be 50m of straight road?
Where did you hear that?
#Post#: 32812--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: The Rookie
Date: August 9, 2024, 9:38 am
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--- Quote from: yuletwigtool--[ link ---
>
> I had heard some while back that something like 50m of
straight line roadway was required in order to get a head-on
reading, but this may have been for older equipment idk
>
--- End Quote ---
even at 60mph it takes the measurement while the car travels a
little over a cars length
I’m guessing that like many speed camera ‘facts’ it was heard in
a pub? It’s never been true, older or newer equipment.
#Post#: 32854--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: tonys
Date: August 10, 2024, 2:14 am
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--- Quote from: yuletwigtool--[ link ---
>
> I had heard some while back that something like 50m of
straight line roadway was required in order to get a head-on
reading, but this may have been for older equipment idk
--- End Quote ---
If the road isn't straight then the device will under-read a
little.
#Post#: 32911--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: Rallyman72
Date: August 10, 2024, 3:52 pm
---------------------------------------------------------
Most speed awareness courses were held on line during Covid and
I believe that this has continued since, it was certainly the
case when I did mine two years ago.
#Post#: 37846--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: yuletwigtool--[
Date: September 22, 2024, 11:22 am
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--- Quote from: Southpaw82 link ---
>
> If the reading is taken in 1/3rd of a second, why would there
need to be 50m of straight road?
>
> Where did you hear that?
>
--- End Quote ---
Can't remember for sure, it would have been some time ago and
this is based on other assumptions and not on the fact that the
reading is done within 1/3 second and used as the only fact for
speeding, ie the other assumptions perhaps being that an instant
of over-speed may not be considered to 'define' speeding, such
as an instance of over acceleration at gear change and that may
be something like 2 secs may have been used so an accommodating
straight stretch would be considered speeding - but this is just
retrospective assessment of what it may have been before I found
out it what I was told above
#Post#: 37854--------------------------------------------------
Re: Speeding - 30mph zone - NIP
DIR By: Southpaw82
Date: September 22, 2024, 1:07 pm
---------------------------------------------------------
--- Quote from: yuletwigtool--[ link ---
>
> [quote author=Southpaw82 link=topic=2768.msg32805#msg32805
date=1723212253]
> If the reading is taken in 1/3rd of a second, why would there
need to be 50m of straight road?
>
> Where did you hear that?
>
--- End Quote ---
Can't remember for sure, it would have been some time ago and
this is based on other assumptions and not on the fact that the
reading is done within 1/3 second and used as the only fact for
speeding, ie the other assumptions perhaps being that an instant
of over-speed may not be considered to 'define' speeding, such
as an instance of over acceleration at gear change and that may
be something like 2 secs may have been used so an accommodating
straight stretch would be considered speeding - but this is just
retrospective assessment of what it may have been before I found
out it what I was told above
[/quote]
Those are certainly words…
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