An incompetence of engineers... Re: slug causes traffic light failure

[Clive]

SCOOT (http://www.scoot-utc.com/) is widely used in the UK to network
traffic lights. In London around 1600 sets of lights are controlled by the
central SCOOT system.
The original SCOOT was conceived decades ago by the Depart/Ministry of/for
Transport and TRRL, now TRL, and implemented by Plessey, STC and Ferranti
as I recall. Plessey became Siemens and Ferranti's interests were bought
by Peek.

Anybody remember the "link lights" in Slough? If you were travelling
at 30mph you hit every one green but at 35, you'd soon be stopped by a
red one. I remember driving through them so I think they might predate
extending the M4 beyond Maidenhead and even that bit was only two lanes
in those days.

[Yokel]

Post by Clive

SCOOT (http://www.scoot-utc.com/) is widely used in the UK to network
traffic lights. In London around 1600 sets of lights are controlled by the
central SCOOT system.
The original SCOOT was conceived decades ago by the Depart/Ministry of/for
Transport and TRRL, now TRL, and implemented by Plessey, STC and Ferranti
as I recall. Plessey became Siemens and Ferranti's interests were bought
by Peek.

Anybody remember the "link lights" in Slough? If you were travelling
at 30mph you hit every one green but at 35, you'd soon be stopped by a
red one. I remember driving through them so I think they might
predate extending the M4 beyond Maidenhead and even that bit was only
two lanes in those days.

If they really want people to obey the speed limit in built-up areas,
this is the sort of thing required.

What normally happens is that the lights aren't linked, so the optimum
strategy (as regards journey time rather than points on licence) is to
keep up with the chap in front regardless. Those wimpish enough to
attempt to obey the law will find a gap opens up in front, which the
next set of traffic lights will "detect" and so change against you.

In unfavourable circumstances, this can happen several times and add
quite a few minutes to your journey across town. This may be one of the
reasons for the style of driving you often see on busy urban roads.

If anyone in the Highways Agency is reading this, any chance of having
this examined and added to official guidance? If you have friends who
work there, pass this on!

[Peter Campbell Smith]

Post by Yokel
What normally happens is that the lights aren't linked, so the optimum
strategy (as regards journey time rather than points on licence) is to
keep up with the chap in front regardless. Those wimpish enough to
attempt to obey the law will find a gap opens up in front, which the
next set of traffic lights will "detect" and so change against you.
In unfavourable circumstances, this can happen several times and add
quite a few minutes to your journey across town. This may be one of
the reasons for the style of driving you often see on busy urban
roads.
If anyone in the Highways Agency is reading this, any chance of having
this examined and added to official guidance? If you have friends who
work there, pass this on!

I don't work for the HA, though have had conversations with them in the
past. Their message is roughly that the goal of SCOOT and of the HA is
to maximise throughput of traffic, which may not equate to minimising
the transit time of individual vehicles.

As a simple illustration, the throughput of a crossroads is impacted
every time the lights change. The throughput could therefore be
increased by changing say only every 15 minutes. However, that would
not please those who arrived just as the light turned red.

Peter