I'm having a really hard time seeing how this is any different than a traffic light being out. If "me-go-you-go" fails, why don't they just have a traffic officer out there directing traffic manually?
CityLink spokeswoman Kate Murphy says the tunnels had to close as a precaution.
"It's not just overhead signs [that are not working], it's also our safety systems
as well," she said.
"For example, in the tunnels the deluge systems or the smoke extraction systems
which we may use in an emergency, we can't actually operate those as well,
which is why we've had to take the dramatic measure of actually closing the
tunnels."The variable speed signs always have extra signs along the lines of "(80) if variable limit sign is disabled" as a fallback.
Not being able to handle leaks, fume buildup, fires and other emergency conditions is a completely different story.
As much as I don't want to sound like a conspiracy person, that level of connection between those components is a bit too much to believe. Especially in Australia where they have insanely high standards for construction/electrical engineering.
This is why they say computer glitch and count on the majority of non technical people to not question it.
If the system allowed the user to do something that impacted safetey in such a way, then the computer glitch is that the computer should stop that sort of thing happening. Human error happens a lot and you have to account for it in your designs.
Of course there are times when you have to trust the user because it is not practical to do those tests (in which case the human should have procedure to follow that mitigates the risk), and instances where the user wil override the checks (when the machines say "I really don't think you should do X because Y, click 'I understand the consequences of my propsosed action' to proceeed") - then it is genuinly human error is something goes wrong.
Point of trivia: before the current toll road company was given its mandate, our main east-west bridge (the Westgate) held the distinction of being one of the very few toll roads in the world that stopped being tolled when planned, when the cost was paid off. A few years of free travel, then this company was given the rights to the road just beyond the bridge...
The tunnels never were public roads, they didn't exist. You can still drive on pretty much the entire length of the West Gate Freeway, right up to the tunnel portals without paying tolls. There are some short sections of motorway though that were previously un-tolled but are now tolled, though there has been some pretty extensive upgrades.
That said I'm no way in favour of City Link, but the real core 'arterial' for urban commuting is our public transport system. :-)
There are reports in the local press of these kinds of problems: "CityLink says it closed the tunnels because the IT problem affected incident detection and safety systems that are activated in the case of an accident. The network problem also affected the back-up system." ~ http://www.heraldsun.com.au/news/breaking-news/melbourne-tun...
And references are being made about inability to communicate to remote devices via the network, "lost the ability to communicate" with its incident detection and safety systems." ~ http://www.itnews.com.au/News/317694,citylink-glitch-shuts-m...
These are tunnels over 3km long. You can't have cops down there without breathing apparatus - even if the extractors were safely operating.