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

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.

trainmanUK wrote:

TFL for London.

giggle

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

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

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

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

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.

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)

"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.