Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 10 Page 101 of 265
The near side pedestrian sequence includes an extendable all-red period which
extends the inter-green time between the pedestrian phase and any conflicting
vehicle phases.
The complete inter-green consists of:
 a fixed minimum red clearance time (PBT),
 an extendable red period (CMX) plus its switched clearance period (CDY),
 a fixed two second vehicle red/amber time
The fixed part of the inter-green from a near side pedestrian phase to a vehicle
phase is controlled by larger of either:
The configured inter-green time (IGN)
OR
The minimum clearance time (PBT) plus the red/amber time.
The controller will use the configured inter-green time unless that would allow the
vehicle red/amber time to start before the minimum red clearance time set by PBT
has finished, i.e. when IGN is set lower than PBT plus two seconds. If a customer
does not specify an inter-green time, a value of 5 seconds will be used.
Consider the example below.
IGN:7
2
R/A
CMX+CDYPBT
PED:
VEH1:
IGN:5
ign
GREEN
RED GREEN
RED
R/A
VEH2:
RED GREEN
ign
Figure 18 – Pedestrian Clearance and Intergreen Times
The configured inter-green time (IGN:5) for PED to VEH1 is set below the required
minimum clearance time (PBT:4) plus the vehicle red/amber time (two seconds).
Therefore the actual inter-green time (shown as ‘ign’) would run longer than the
configured inter-green value and actually run for six seconds governed by the PBT
and vehicle red/amber time. This would be the normal case on a stand-alone stream
where the IGN time is zero.