Download ST950 FACILITIES HANDBOOK

Mobility Division, Traffic Solutions
Sopers Lane, Poole, Dorset, BH17 7ER
17
INTERGREEN DELAYS
17.1
Introduction
An Intergreen Delay allows the intergreen between a phase losing right of way (ROW)
and one or more phases gaining ROW to be extended. Other facilities (e.g. RLM) may
still prevent a phase from gaining ROW even though the Intergreen Delay facility may
allow it to gain ROW.
The facility provides for 64 Intergreen Delays.
An Intergreen Delay is characterised by the following configuration items:
A single phase which enables the Intergreen Delay when it loses ROW
One or more phases which are delayed if they are gaining ROW when the
Intergreen Delay is enabled
A input which whilst active ensures the gaining ROW phases are delayed; this
can be a detector input or a scratch bit output from Special Conditioning.
A maximum intergreen period (MIP) which terminates the Intergreen Delay when
it expires
While the input or the input's extension are active, the appearance of the specified
phases gaining ROW is delayed until either the input and its extension go inactive or
the maximum intergreen period is reached. The phases then gain ROW. If the
configured intergreen times between the phases request an offset or staggered
appearance, this is maintained and this also takes Phase Delays in to account.
Intergreen Delays are configured using the IC4 Configurator. The MIP can also be
subsequently modified via the handset or web page.
The configured Intergreen Delays can be viewed on the Controller – Phases –
Intergreen Delays web page. The “Controller – Phases – Status” Web page indicates
whether a given phase is prevented from gaining ROW by an Intergreen Delay.
17.1.1 Comparison with the Extend All Red Facility
Both Intergreen Delay and Extend All Red facilities use inputs to delay the appearance
of phases during a stage movement.
An Intergreen Delay extends the intergreen to the specified gaining ROW phases and
is limited by the MIP. Naturally it does not affect any other phases and nor does it
depend on the stage movement. The Maximum Intergreen Period is timed from the
start of the intergreen period, i.e. from when the phase loses right of way.
An Extend All Red extends the all red period of a stage movement and is limited by the
maximum all red period. Normally the Extend All Red facility affects multiple phases to
extend the whole 'all red' period of the interstage movement. The maximum all-red
period is timed from the point the all-red extension begins to delay the appearance of
the phases.
17.1.2 Possible Uses for Intergreen Delays
Possible uses for Intergreen Delays are:
Turning Traffic – Vehicles turning across the intersection may be delayed by vehicles
travelling in the opposite direction (e.g. right turning traffic when driving on the left). If
Security classification
Unrestricted
Version
4
Last Editor
Paul Cox
Document Name
ST950 Facilities Handbook
Copyright © Siemens plc 2015. All Rights Reserved.
Page
104 of 303
Status
Issued
Date
16-Jul-2015
Document No.
667/HB/46000/001
Mobility is a division of Siemens Plc