Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 10 Page 95 of 265
6.9.3 Termination Type 2
The phase terminates when a specified associated phase loses ROW. The
associated phase must be a fixed phase.
The normal use for this type of phase is an indicative green arrow.
6.10 Early Termination of Phases
Once a phase has gained ROW in a stage it cannot normally be terminated before
the end of the stage.
If early termination of a phase is required, usually for a pedestrian phase, it can be
achieved by using two consecutive stages. The phase that is to terminate early is
allocated to the first stage while the other phases that are to stay at ROW are
allocated to both stages.
The normal method of operation is for a demand to be inserted for the second stage
when the first stage becomes active. A stage change will then occur following the
expiry of the minimum green of the early terminating phase.
The controller is programmed so that the stage change occurs without an interstage
to give the appearance of one stage instead of two.
Variations of this method of control may also be achieved.
6.11 Pedestrian Phase Types
This section describes the various different types of pedestrian phase supported by
the ST900 traffic controller.