Traffic light problem in Golders Green
 

Late at night, the traffic lights on Finchley Road at the junction of West
Heath Avenue often go red for a couple of seconds before reverting to green.
This is far too short for another traffic or pedestrian phase to have
occurred in between. It seems that sensors facing into the side roads detect
that there is no traffic there and that this causes the green phase for the
side roads to be skipped, but unfortunately the other lights have flipped to
red before this decision is made. Surely this must be a mistake rather than
design.

How are the phases of traffic lights controlled anyway? Is there a program
inside them written in some standard programming language, and someone has
put the IF statement in the wrong place? I would have guessed that the
danger of conflicting greens would have prevented the control sequence from
being written in a standard language and that something much less flexible
would have been used, which would have prevented the error I see at this
junction.

Traffic light problem in Golders Green
 

"Basil Jet" wrote in message
...

Late at night, the traffic lights on Finchley Road at the junction of West
Heath Avenue often go red for a couple of seconds before reverting to
green. This is far too short for another traffic or pedestrian phase to
have occurred in between. It seems that sensors facing into the side roads
detect that there is no traffic there and that this causes the green phase
for the side roads to be skipped, but unfortunately the other lights have
flipped to red before this decision is made. Surely this must be a mistake
rather than design.

It is quite common for lights to run though a short cycle when they have not
been triggered for some time. I presume the controller is running some sort
of error check sequence.

Colin Bignell

Traffic light problem in Golders Green
 

On Thu, 16 Jul 2009 00:23:13 +0100
"Basil Jet" wrote:
red before this decision is made. Surely this must be a mistake rather than
design.

Don't bet on it. perhaps it wasn't intentional to start with but when it was
realised it would slow traffic down they probably decided not to fix it.
The lights on the purley way in croydon still go red to let imaginary cars out
of empty shop car parks and industrial estates at 1am. Don't tell me thats
not done on purpose just to slow down traffic who might be trying to get a
move on on an empty dual carraigeway. You're not allowed to get anywhere
quickly in london.

How are the phases of traffic lights controlled anyway? Is there a program
inside them written in some standard programming language, and someone has

They probably used to run off an 4 or 8 bit microcontroller with the program
written in assembler, but these days it seems that you can't be a self
respecting embedded systems designer without specifying that the hardware must
be a PC running Windoze because the only thing you can code in is VB.

B2003

Traffic light problem in Golders Green
 

On 16 July, 11:39, wrote:
On Thu, 16 Jul 2009 00:23:13 +0100

"Basil Jet" wrote:
red before this decision is made. Surely this must be a mistake rather than
design.

Don't bet on it. perhaps it wasn't intentional to start with but when it was
realised it would slow traffic down they probably decided not to fix it.
The lights on the purley way in croydon still go red to let imaginary cars out
of empty shop car parks and industrial estates at 1am. Don't tell me thats
not done on purpose just to slow down traffic who might be trying to get a
move on on an empty dual carraigeway. You're not allowed to get anywhere
quickly in london.

How are the phases of traffic lights controlled anyway? Is there a program
inside them written in some standard programming language, and someone has

They probably used to run off an 4 or 8 bit microcontroller with the program
written in assembler, but these days it seems that you can't be a self
respecting embedded systems designer without specifying that the hardware must
be a PC running Windoze because the only thing you can code in is VB.

B2003

I should report it to TFL for London. I had a similar problem at a
junction a couple of years ago. it turned out the sensor for
detecting cars was broken so between 2200 and 0600 it would not let
any cars out of the side road. Had to pass through a red light
(carefully) with the permission of the police car who was waiting
behind me.

Traffic light problem in Golders Green
 

In article ,
wrote:
Don't bet on it. perhaps it wasn't intentional to start with but when it was
realised it would slow traffic down they probably decided not to fix it.
The lights on the purley way in croydon still go red to let imaginary cars out
of empty shop car parks and industrial estates at 1am. Don't tell me thats
not done on purpose just to slow down traffic who might be trying to get a
move on on an empty dual carraigeway. You're not allowed to get anywhere
quickly in london.

It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

--
:wq

Traffic light problem in Golders Green
 

On Thu, 16 Jul 2009 17:05:16 +0100
Mike Bristow wrote:
of empty shop car parks and industrial estates at 1am. Don't tell me thats
not done on purpose just to slow down traffic who might be trying to get a
move on on an empty dual carraigeway. You're not allowed to get anywhere
quickly in london.

It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

Except that each set of lights has a rather expensive red light camera
mounted in both directions.

B2003

Traffic light problem in Golders Green
 

On Thu, 16 Jul 2009 00:23:13 +0100, "Basil Jet"
wrote:

You can avoid the junction by using the passover

dies

Guy
--
http://www.chapmancentral.co.uk

Traffic light problem in Golders Green
 

On Thu, 16 Jul 2009 00:23:13 +0100, Basil Jet
wrote:
How are the phases of traffic lights controlled anyway? Is there a
program inside them written in some standard programming language,

Pretty much, yes. It's on a PROM but I can't remember what language is
used.

and someone has put the IF statement in the wrong place? I would have
guessed that the
danger of conflicting greens would have prevented the control sequence
from being written in a standard language and that something much less
flexible would have been used, which would have prevented the error Isee
at this junction.

Allegedly, a new PROM is created for each junction, while temporary lights
run on a standard sequence. Often the PROM is re-blown after the previous
one has been shown (by long queues) to be wrong.

I say allegedly because at one junction I know, the westbound stops before
the eastbound if no vehicles are detected there. At this junction this is
completely pointless, as both westbound and eastbound traffic is only
allowed to go straight on.

Colin McKenzie

--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.

Traffic light problem in Golders Green
 

Colin McKenzie wrote:

at one junction I know, the westbound stops
before the eastbound if no vehicles are detected there. At this
junction this is completely pointless, as both westbound and
eastbound traffic is only allowed to go straight on.

Are there perhaps separate pedestrian crossings for the two halves of the
road?

Traffic light problem in Golders Green
 

trainmanUK wrote:

TFL for London.

giggle

Traffic light problem in Golders Green
 

On Fri, 17 Jul 2009 01:50:41 +0100, Basil Jet
wrote:

Colin McKenzie wrote:
at one junction I know, the westbound stops
before the eastbound if no vehicles are detected there. At this
junction this is completely pointless, as both westbound and
eastbound traffic is only allowed to go straight on.

Are there perhaps separate pedestrian crossings for the two halves of the
road?

No - there is no crossing facility at all east of the junction, and two
eastbound lanes to get across.

Colin McKenzie



--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.

Traffic light problem in Golders Green
 

"Basil Jet" wrote in message
...

Late at night, the traffic lights on Finchley Road at the junction
of West Heath Avenue often go red for a couple of seconds before
reverting to green. This is far too short for another traffic or
pedestrian phase to have occurred in between. It seems that sensors
facing into the side roads detect that there is no traffic there and
that this causes the green phase for the side roads to be skipped,
but unfortunately the other lights have flipped to red before this
decision is made. Surely this must be a mistake rather than design.

It is quite common for lights to run though a short cycle when they
have not been triggered for some time. I presume the controller is
running some sort of error check sequence.

If it's common, where else does it happen? There is a pedestrian crossing in
Harrow which has phantom pedestrian phases, but apart from that, I've never
noticed it elsewhere.

Traffic light problem in Golders Green
 

"Basil Jet" wrote in message
...
"Basil Jet" wrote in message
...

Late at night, the traffic lights on Finchley Road at the junction
of West Heath Avenue often go red for a couple of seconds before
reverting to green. This is far too short for another traffic or
pedestrian phase to have occurred in between. It seems that sensors
facing into the side roads detect that there is no traffic there and
that this causes the green phase for the side roads to be skipped,
but unfortunately the other lights have flipped to red before this
decision is made. Surely this must be a mistake rather than design.

It is quite common for lights to run though a short cycle when they
have not been triggered for some time. I presume the controller is
running some sort of error check sequence.

If it's common, where else does it happen? There is a pedestrian crossing
in Harrow which has phantom pedestrian phases, but apart from that, I've
never noticed it elsewhere.

Phantom pedestrian phases are often cause by the local scrotii jamming a
match in the button....

Traffic light problem in Golders Green
 

On Jul 19, 9:02*am, "Ian" wrote:

"Basil Jet" wrote:

"Basil Jet" wrote:

Late at night, the traffic lights on Finchley Road at the junction
of West Heath Avenue often go red for a couple of seconds before
reverting to green. This is far too short for another traffic or
pedestrian phase to have occurred in between. It seems that sensors
facing into the side roads detect that there is no traffic there and
that this causes the green phase for the side roads to be skipped,
but unfortunately the other lights have flipped to red before this
decision is made. Surely this must be a mistake rather than design.

It is quite common for lights to run though a short cycle when they
have not been triggered for some time. I presume the controller is
running some sort of error check sequence.

If it's common, where else does it happen? There is a pedestrian crossing
in Harrow which has phantom pedestrian phases, but apart from that, I've
never noticed it elsewhere.

Phantom pedestrian phases are often cause by the local scrotii jamming a
match in the button....

Really? I've never come across that before.

Traffic light problem in Golders Green
 

"Ian" wrote in message
...

If it's common, where else does it happen? There is a pedestrian crossing
in Harrow which has phantom pedestrian phases, but apart from that, I've
never noticed it elsewhere.

Phantom pedestrian phases are often cause by the local scrotii jamming a
match in the button....

Hmm. No it should time out after a while and should send a constant input
alarm I think.

New crossings are button and beacon input - so you can push the button but
if nothing activates the sensor it should just 'wait' on calling the
pedestrian route till it gets an input then it will call it in the usual
way.

Junctions that go mad its often the Scoot loops broken/beacon, or something
in the chain broken and the controller is missing an input or another
action. Lights stuck on a phase usually send an alarm back after (I think
120 Sec on red)

Its also worth pointing out that a number (quite a lot) of junctions and
things are 'on-line' anyway feeding the Scoot data back to the GIS
application. The knock on of that is you can then 'control' the junction
(usually with defined configurations against time periods)

If you want to report the fault/problem then its TfL streets you want - and
they will either take the road junction details, or on the side of the
controller cab there is a number (XX/XXX) that's the site specific ID and
they will be quite happy with that too.

Traffic light problem in Golders Green
 

On Thu, 16 Jul 2009 17:05:16 +0100, Mike Bristow
wrote:

In article ,
wrote:
Don't bet on it. perhaps it wasn't intentional to start with but when it was
realised it would slow traffic down they probably decided not to fix it.
The lights on the purley way in croydon still go red to let imaginary cars out
of empty shop car parks and industrial estates at 1am. Don't tell me thats
not done on purpose just to slow down traffic who might be trying to get a
move on on an empty dual carraigeway. You're not allowed to get anywhere
quickly in london.

It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

That, as I understand that would be illegal. Even temp traffic lights
at road works have to have sensors.

Microwave sensors are not expensive in the whole scheme of things when
compared with the cost of digging holes for the lights themselves and
pulling cables.

Derek

Traffic light problem in Golders Green
 

In article ,
Derek Geldard wrote:
It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

That, as I understand that would be illegal.

I find that difficult to believe. I don't think the lights at the
junction of Bush Road and Leytonstone High Road have sensors, for
example. they certainly don't have the obvious ones that sit on
top of the lights (although they might have a loop in the road
itself, I suppose).

I don't think the traffic management at that site would be improved
by them, either, so the only thing they would add is increased
maintance costs, and more things to break, for no benefit.



--
:wq

Traffic light problem in Golders Green
 

On Tue, 28 Jul 2009 14:27:58 +0100, Mike Bristow
wrote:
In article ,
Derek Geldard wrote:
It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

That, as I understand that would be illegal.

I find that difficult to believe. I don't think the lights at the
junction of Bush Road and Leytonstone High Road have sensors, for
example. they certainly don't have the obvious ones that sit on
top of the lights (although they might have a loop in the road
itself, I suppose).


No traffic lights on a public road, whether temporary or permanent,
can be installed without sensors. Almost all permanent lights have
sensor loops in the road surface. Only a few have the sensors on top
of the traffic light that are universal in temporary installations.

Traffic light problem in Golders Green
 

Bruce wrote on 28 July 2009 15:34:18 ...
On Tue, 28 Jul 2009 14:27:58 +0100, Mike Bristow
wrote:
In article ,
Derek Geldard wrote:
It's probably done on purpose on grounds of cost: lights with a
fixed (or timed) pattern will be cheaper to buy and maintain than
lights with sensors etc.

That, as I understand that would be illegal.

I find that difficult to believe. I don't think the lights at the
junction of Bush Road and Leytonstone High Road have sensors, for
example. they certainly don't have the obvious ones that sit on
top of the lights (although they might have a loop in the road
itself, I suppose).

As Bruce says, most permanent lights have detector circuits embedded in
the road surface. At that junction, Google Street View seems to show an
anti-skid surface, which would have covered the tar lines indicating
where the detectors are.

No traffic lights on a public road, whether temporary or permanent,
can be installed without sensors.

What law or regulation specifies that? I'm not aware of one. Certainly
it's normal to have sensors, but I thought that fixed-time signals were
still legal. A Highways Agency press release from 2006 talks about a
fixed time traffic light installation at York being upgraded, and
Worcestershire County Council's site says that fixed time temporary
lights need their written approval, so in both cases it seems that fixed
time signals are not illegal.
--
Richard J.
(to email me, swap 'uk' and 'yon' in address)

Traffic light problem in Golders Green
 

"Mike Bristow" wrote in message
...

I find that difficult to believe. I don't think the lights at the
junction of Bush Road and Leytonstone High Road have sensors, for
example.

Is it 'LEYTONSTONE HIGH RD / BUSH RD / TESCO SERVICE RD' ?

There are input sensors for that junction although I'm not sure without
looking further what type

The junction in the OP's message is the same - no record of anything sensor
wise - but there have been a few faults in the past 6 months. Mostley lamp's
out and little things.

Traffic light problem in Golders Green
 

In article ,
Q wrote:

"Mike Bristow" wrote in message
...

I find that difficult to believe. I don't think the lights at the
junction of Bush Road and Leytonstone High Road have sensors, for
example.

Is it 'LEYTONSTONE HIGH RD / BUSH RD / TESCO SERVICE RD' ?

Yes. And now I think about it, it's the tesco service road that
probably needs the sensor.


--
:wq