Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 10 Page 82 of 265
6
6
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6.1 Facilities
There are up to 32 phases (A to Z and A2 to F2) available for use as any of the
following types of phase:
 Traffic
 Pedestrian
 Green arrow, filter or indicative
 LRT vehicle
 Dummy
 Switched sign.
Traffic, pedestrian and green arrow phases are considered as real phases and
require phase hardware as well as phase software.
Dummy phases require only phase software. As no phase hardware is required the
dummy phases are allocated after the real phases. Switched sign phases do not
require phase software. They only require the software necessary for switching them
on and off and phase hardware.
It is possible to use phase software for a dummy phase and phase hardware for a
switched sign phase.
(N.B. For more details on specific lamp sequences for particular countries of the
world, refer to Section 28)
6.2 Types of Phases
6.2.1 Traffic Phase
A traffic phase controls vehicle movements via a 3-aspect signal comprising red,
amber and green. The green aspect may be a left turn or a right turn or straight-
ahead green arrow as required by the method of control.
The standard signal sequence is as follows:
At no ROW
- RED
Changing to ROW - RED/AMBER
At ROW - GREEN
Changing to no ROW - AMBER
At no ROW
- RED
The red/amber period is normally 2 seconds and the amber period is normally 3
seconds.
If required, alternative signal sequences, e.g. RED-GREEN-AMBER-RED, can be
easily configured on the lamp sequence screens (‘non-UK’ configurations only).