SA's Traffic Systems

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Signal Controllers

It looks like there are several controllers out there currently. I remember back in
the early 2000's when the controllers on one of the most important roads in the
city were purely relay logic driven and time controlled. You stood next to the
controller and you could hear the relays ticking as the signals changed and the
red man flashed. Of course now we're using programmable computer based
controllers. The primary added advantages are ease of adjustment to cycles and
phases and remote control, particularly for emergency services.

Click on the arrows to view the pictures on each controller. Click on the
pictures themselves to view the full size original picture.

Aldridge ATSC4

I found this badly damaged controller just asking to have pictures taken of. Amazingly
despite the damage (trust me, I couldn't capture just how badly damaged this enclosure
was) all components and cables still kept the signals functioning as normal.
The controller had much less in it than I thought and I was able to confirm some
speculations I made about the system. Sure enough it's connected to a network for
remote control and it talks to nearby "sites" to closely synchronise green and red signals
to keep city traffic flow smooth. I wasn't sure on the voltage of the signal lights
themselvesbut I found no isolated supply for the signal lights, therefore they must
be 240V. Queensland seems to use extra low voltage for their signal lights.