OT: Traffic monitoring cables across road
Caecilius
devices that consist of two parallel cables running across the road at
right angles to the direction of traffic are called and what they are used
for?
They seem to have appeared recently on the roads in my area (Medway in
Kent), and I recall seeing them last year as well - perhaps they are
seasonal?
I presume that they are placed by the council, and record the quantity and
speed of traffic (or, more specifically of pairs of wheels). However, does
anyone know what the data is used for? Is it used to decide where to place
speed cameras or some other neferious purpose?
Newshound
"Caecilius" <nos...@spamless.invalid> wrote in message
news:jpod731pb2bcf8hhp...@4ax.com...
> This is a bit off-topic, but does anyone know what the traffic monitoring
> devices that consist of two parallel cables running across the road at
> right angles to the direction of traffic are called and what they are used
> for?
>
for traffic surveys. If you think about it, you will see that with two pipes
"they" can work out the speed, wheelbase, and number of axles for each
vehicle. So they can more or less differentiate between motorbikes, cars,
buses, and lorries of different sizes. (If two vehicles pass in opposite
directions at the same time the software drops the data in the "too
difficult" box).
R.P.McMurphy
"Caecilius" <nos...@spamless.invalid> wrote in message
news:jpod731pb2bcf8hhp...@4ax.com...
Inductive loops, yep they're used for counting cars.
Steve
Andy Hall
It's certainly nefarious.
There will be the council traffic department and then an outside firm
of consultants to do the work, thus doubling the cost.
The rest is detail.
Andrew Mawson
"R.P.McMurphy" <r.p.mcmu...@ntlworld.com> wrote in message
news:4676ee46$0$8741$ed26...@ptn-nntp-reader02.plus.net...
IME they are usually pneumatic and not inductive loops. The permanent
buried ones for trafic lights are inductive, wheras the temporary
surface mounted ones for trafic census purposes are a rubber tube,
with a metal plug at the far end and a pressure sensor within the
instrument, which is usually padlocked to a lamp post.
AWEM
fred
<news...@fairadsl.co.uk> writes
to be used to collect data when a complaint was made of excessive
speeding on a stretch of road, the stats received could be used to justify a
speed trap on that stretch.
--
fred
Plusnet - I hope you like vanilla
Newshound
> It's certainly nefarious.
>
> There will be the council traffic department and then an outside firm of
> consultants to do the work, thus doubling the cost.
>
> The rest is detail.
>
the work (tripling the cost....)
(a consultant)
Andy Burns
> the temporary
> surface mounted ones for trafic census purposes are a rubber tube,
> with a metal plug at the far end and a pressure sensor within the
> instrument, which is usually padlocked to a lamp post.
Some of the newer ones I've seen are a metal box big enough for e.g. a
couple of car batteries with a 15' post coming out of it, and a camera
on top, usually the box chained around the base of a lamp-post and the
camera-post is duct taped to the lamp-post higher up for support,
presumably there is a video or hard disk recorder inside, they only seem
to stay at any one site for a day.
R.P.McMurphy
"Andrew Mawson" <andrew@no_spam_please_mawson.org.uk> wrote in message
news:2eidnb8Zr_d...@bt.com...
yep your right, if they are imbedded they are likely inductive loops, on the
surface they are the pneumatic type of counter.
Steve
Steve
The Medway Handyman
> This is a bit off-topic, but does anyone know what the traffic
> monitoring devices that consist of two parallel cables running across
> the road at right angles to the direction of traffic are called and
> what they are used for?
>
> They seem to have appeared recently on the roads in my area (Medway in
> Kent), and I recall seeing them last year as well - perhaps they are
> seasonal?
Where are they?
Knowing Medway Council its bound to cost us money :-(
--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257
Owain
> This is a bit off-topic, but does anyone know what the traffic monitoring
> devices that consist of two parallel cables running across the road at
> right angles to the direction of traffic are called and what they are used
> for?
google Lochwynd - they do this sort of thing
Owain
Lurch
<news...@fairadsl.co.uk> mused:
>
>"Caecilius" <nos...@spamless.invalid> wrote in message
>news:jpod731pb2bcf8hhp...@4ax.com...
>> This is a bit off-topic, but does anyone know what the traffic monitoring
>> devices that consist of two parallel cables running across the road at
>> right angles to the direction of traffic are called and what they are used
>> for?
>>
>I read an article on these some time ago which said they were basically used
>for traffic surveys. If you think about it, you will see that with two pipes
>"they" can work out the speed, wheelbase, and number of axles for each
>vehicle. So they can more or less differentiate between motorbikes, cars,
>buses, and lorries of different sizes.
How do they do that then? How does it know the difference between 2
twin axle vehicles and one 4 axle vehicle? Ho does it know when a 3
axle vehicle ends and a 2 axle one starts?
Why are there devices with 1 or 2 tubes?
--
Regards,
Stuart.
nightjar
"Caecilius" <nos...@spamless.invalid> wrote in message
news:jpod731pb2bcf8hhp...@4ax.com...
> devices that consist of two parallel cables running across the road at
> right angles to the direction of traffic are called and what they are used
> for?
They are normally part of a traffic survey, aimed at deciding how heavy the
traffic is in relation to the road designed capacity. The usual process is
to start with a manual count, which involves several people sitting in cars
at the same spot for a whole day, operating a cumulative counter for every
vehicle type that passes the bit of road they are responsible for - there
will usually be at least one car for each direction of travel and several
roads around a junction may be surveyed at the same time. That gives data on
the type of traffic, from which axle numbers are derived. The rubber tubes
then operate pneumatic counters, which count the axles and direction of
travel over a much longer period. They can also check traffic speed at
different times, to determine when the road is congested. Combining the data
gives a pattern of road use and is used to help plan road development in the
area. A traffic census may also form part of the survey, to decide whether
the traffic is primarily local or is passing through.
Colin Bignell
Ian White
>> IME they are usually pneumatic and not inductive loops. The permanent
>> buried ones for trafic lights are inductive, wheras the temporary
>> surface mounted ones for trafic census purposes are a rubber tube,
>> with a metal plug at the far end and a pressure sensor within the
>> instrument, which is usually padlocked to a lamp post.
>>
>> AWEM
>>
>>
>
>yep your right, if they are imbedded they are likely inductive loops,
And the cut-outs in the road are... loop shaped. Although buried loops
are intended to be permanent installations, they aren't all in
continuous use, as the sensor equipment may well be moved around from
site to site.
Loop sensors are basically metal detectors, but with two loops per lane
and a bit of clever computing they can also work out speed, length, gap
between following vehicles, and even classify vehicles into cars, vans,
rigid lorries, artics etc.
>on the surface they are the pneumatic type of counter.
Those are single-ended tubes, as someone described. They are only ever
temporary, as they wouldn't survive as a permanent installation. Usually
they are used by county traffic departments to answer specific local
questions that aren't covered by their long-term monitoring schemes.
Counties and the Highways Agency have been collecting traffic data for
years, and there has been an upsurge in activity because of maintenance
contracts that are formula-funded according to the volume, speed and
types of traffic.
One thing all of these loop and tube sensors have in common is that they
are strictly for collecting traffic data. They aren't interested in
individuals. Above all, this type of equipment is categorically not
capable of 'prosecution quality' speed measurements.
--
Ian White
The Natural Philosopher
slow down for em or you will end up with a nightmare of road furniture.
The Natural Philosopher
The distance between the tubes is small enough so that long duration
pluses due to one wheel and then the next wheel are discounted.
2-tube devices monitor speed as well as traffic density.
Cutting the tubes or moving them further apart will render them irrelevant.
Bob Eager
> Those are single-ended tubes, as someone described. They are only ever
> temporary, as they wouldn't survive as a permanent installation.
Apart from the pairs of pneumatic tubes that used to be (may still be)
embedded in roads as traffic light sensors...
--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com
John
"Owain" <owain...@stirlingcity.coo.uk> wrote in message
news:118220385...@proxy02.news.clara.net...
Really interesting web site. Thanks
Ian White
Think about the information you get, and what you could then do with it.
One pneumatic tube can only count wheel crossings, and you don't even
know which direction the vehicles are travelling. Two tubes stretched
across a two-lane road will give direction and a rough indication of
speed, though the pulses of air pressure only give poor timing
information. Rather than precise wheel crossings, loops detect
generalised lumps of metal overhead, but overall they tend to give more
reliable results.
With some real-time computing capacity right there at the roadside, they
can sweat a surprising amount of information out of the raw sensor
signals. All the differences that you can see with your own eyes have
some equivalent in terms of timings and signal levels.
Differentiation between types of vehicles is mostly based on timing. For
example, in freely flowing traffic the timing patterns for a 4-axle
vehicle and two 2-axle vehicles are very different (or if vehicles
really are crawling nose-to-tail, they will know that from the speed
information). Also, wheels that belong to the same vehicle will all have
the same speed (within a few percent) and there are only a few common
patterns of wheelbase and length. With loop sensors there is additional
information from the signal level: a long artic will always have some
metal overhead, but in gaps between vehicles the signal drops right out.
Put it all together, and they can infer a lot of information from very
simple sensors. It isn't 100% reliable, but close enough for census
work.
--
Ian White
Ian White
>
>> Those are single-ended tubes, as someone described. They are only ever
>> temporary, as they wouldn't survive as a permanent installation.
>
>Apart from the pairs of pneumatic tubes that used to be (may still be)
>embedded in roads as traffic light sensors...
Those are quite rare now. When they wear out, they are almost invariably
replaced by loops, which are the right kind of sensor for traffic lights
because they can also detect stationary vehicles.
--
Ian White
Bob Eager
I agree. They seemed to last a very long time now.
With regard to the stationary vehicles...I always understod that the
tubes worked well because a stationary vehicle would not compress the
tube completely; thus another vehicle passing across the tube, further
along, would still generate an impulse.
Tony Williams
Lurch <myrea...@sjwelectrical.co.uk> wrote:
> How do they do that then? How does it know the difference between
> 2 twin axle vehicles and one 4 axle vehicle? Ho does it know when
> a 3 axle vehicle ends and a 2 axle one starts?
> Why are there devices with 1 or 2 tubes?
One pneumatic tube is used for counting vehicles
and two for counting+speed. And the little grey
stand-on-the-ground electronic boxes used to be
made by a company called Golden River in Bicester.
I've just had a look. They are still there, now
at <www.goldenriver.com>, and now with a range of
vehicle spotting and identification systems that
are positively Big Brother.
--
Tony Williams.
Derek Geldard
wrote:
The council put them out on the road for a couple of months if the
locals start campagning for a pelican crossing for instance.
Then they say the results demonstrate whatever the council want them
to demonstrate.
DG
Mike Barnes
>Bob Eager wrote:
>>
>>Apart from the pairs of pneumatic tubes that used to be (may still be)
>>embedded in roads as traffic light sensors...
>
>Those are quite rare now. When they wear out, they are almost
>invariably replaced by loops, which are the right kind of sensor for
>traffic lights because they can also detect stationary vehicles.
Yes, but is there any evidence that the equipment actually does anything
with that stationary-vehicle information? Time after time I see traffic
lights halting the traffic flow in order to allow non-existent traffic
to cross.
--
Mike Barnes
dennis@home
"Mike Barnes" <mikeb...@bluebottle.com> wrote in message
news:Qfga2Ho$S5dG...@g52lk5g23lkgk3lk345g.invalid...
That is because they can't guarantee to detect all traffic types so they
have the odd short change to allow for it.
The other major cause is some kid sticking the button in on the pedestrian
crossing.
The Natural Philosopher
traffic lights..
David Hansen
<nos...@spamless.invalid> wrote this:-
>However, does anyone know what the data is used for?
Depends on why the recorder is installed.
>Is it used to decide where to place
>speed cameras or some other neferious purpose?
Speed cameras are no more nefarious than any other way of catching
criminals.
--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54
dennis@home
"David Hansen" <SENDdavi...@spidacom.co.uk> wrote in message
news:0fhf73h2a0k1c6ehj...@4ax.com...
> On Mon, 18 Jun 2007 19:59:54 GMT someone who may be Caecilius
> <nos...@spamless.invalid> wrote this:-
>
>>However, does anyone know what the data is used for?
>
> Depends on why the recorder is installed.
>
>>Is it used to decide where to place
>>speed cameras or some other neferious purpose?
>
> Speed cameras are no more nefarious than any other way of catching
> criminals.
But they only catch stupid criminals.. they need to be hidden to catch the
ones that are awake.
David Hansen
<den...@killspam.kicks-ass.net> wrote this:-
>> Speed cameras are no more nefarious than any other way of catching
>> criminals.
>
>But they only catch stupid criminals..
Unobservant criminals.
>they need to be hidden to catch the
>ones that are awake.
The criminals made a fuss and party politicians listened to the
"representatives" of the criminals.
The Natural Philosopher
They only catch the careless. They do nothing to catch deliberate law
breakers. They won't be driving a car that belongs to them otr has valid
plates on anyway.
The radar activated speed limit signs are far more effective in slowing
the mostly law abiding motorist.
nightjar
"The Natural Philosopher" <a@b.c> wrote in message
news:118225853...@proxy02.news.clara.net...
Law abiding motorists do not need to slow down. In any case, those signs are
only more effective at slowing drivers within a relatively small geographic
area, for a short time. Points on the licence have a much longer term effect
over a wider area.
Colin Bignell
David Hansen
<nightjar@<insert my surname here>.uk.com> wrote this:-
>Law abiding motorists do not need to slow down.
Indeed.
>In any case, those signs are
>only more effective at slowing drivers within a relatively small geographic
>area, for a short time. Points on the licence have a much longer term effect
>over a wider area.
Indeed. It appears that the number of criminals with points on their
driving licence is beginning to have an effect. Many such criminals
do appear to have moderated their criminal behaviour somewhat.
Obviously some are very determined to continue in their criminal
ways no matter what, but even so this should not be allowed to hide
the fact that many criminals have moderated their criminal
behaviour.
Ian White
>
>> One thing all of these loop and tube sensors have in common is that they
>> are strictly for collecting traffic data. They aren't interested in
>> individuals. Above all, this type of equipment is categorically not
>> capable of 'prosecution quality' speed measurements.
>>
>traps.
>
Would you like to explain more about that - like which "them" you mean,
exactly how they use them; and if somebody is prosecuted, what actually
measured the speed?
--
Ian White
Caecilius
<davi...@nospamblueyonder.co.uk> wrote:
>Where are they?
I know of five on my daily run to school and work:
One on the esplanade
One on the A2 london road in strood
Three on the wainscott bypass (A228 I think)
>Knowing Medway Council its bound to cost us money :-(
Don't get me started :-)
dennis@home
"Ian White" <I...@ifwtech.co.uk> wrote in message
news:ubqwHLf9...@ifwtech.co.uk...
There is a speed trap that consists of two sensors that are stretched across
the road like the census devices.
It doesn't work in the same way and is accurate provided they use the
distance stick to get the spacing.
Ian White
--
Ian White
Lurch
<mikeb...@bluebottle.com> mused:
Some sets of lights will turn to red if you are over the speed limit
to slow you down.
--
Regards,
Stuart.
The Medway Handyman
> On Mon, 18 Jun 2007 22:36:37 +0100, "The Medway Handyman"
> <davi...@nospamblueyonder.co.uk> wrote:
>> Where are they?
>
> I know of five on my daily run to school and work:
>
> One on the esplanade
Not been there recently
> One on the A2 london road in strood
Watling Street?
> Three on the wainscott bypass (A228 I think)
Not spotted those yet.
>
>> Knowing Medway Council its bound to cost us money :-(
>
> Don't get me started :-)
Mutter, mutter :-(
I'm off Rede Court Rd, where are you?
--
Dave
The Medway Handyman
www.medwayhandyman.co.uk
01634 717930
07850 597257
The Natural Philosopher
dennis@home
"The Natural Philosopher" <a@b.c> wrote in message
Why?
manat...@hotmail.com
> On Tue, 19 Jun 2007 09:33:03 +0100, Mike Barnes
Can you give a reference to one that works like that in the UK?
MBQ
Lurch
<manat...@hotmail.com> mused:
No.
--
Regards,
Stuart.