In a lot of ways the Agency model at the city creates these disconnects. TTC, Hydro, CreateTO, etc are all Agencies outside of the regular civil service, and there is no structure to make everything work together. Which is why Hydro are always tearing up recently built sidewalks, or CreateTO can't integrate development into TTC rebuilds. The whole model of how the City delivers services needs a rework if we want it to be more interconnected, which will most likely not be cheap or easy.
This bit isn't quite true.
There is a committee w/reps from all the agencies that meets semi-regularly to coordinate things, and that's what TO Inview was set up for as well. Every agency is supposed to put every project they need to work on, on that platform so everyone else can see what's up; and before anyone plans to do anything they're supposed to check TO Inview to make sure there aren't any conflicts.
Now does the above work as intended? Sometimes............but not as well as you might hope.
There are a lot of reasons for that.
Most utilities, including Rogers/Bell/Telus have a right to rip up anything to make 'emergency' repairs'. The City is generally not allowed to refuse them. That's the single largest chunk of surprise dig-ups.
Then there are things where one agency may not realize they have an issue needing attention with project 'x'; and only find out when someone else starts digging. See, the reconstruction of the streetcar track at Church/Carlton where crews didn't realize the hydro vault was sitting too high to make the current project design work.
There are also departments/agencies which don't make regular use of TO Inview, directions to do so notwithstanding. Parks is bad for this.
Then you just have churn (staff turnover) and low institutional memory, "I didn't know we were supposed to do that, this way, no one told me, there was no flag on the file"
Throw in the odd competence issue.......
Also problematic is that for a variety of reasons projects move up/down the priority list in the schedule; so one agency checks.......oh, the other guys want to do that in 2029, we have lots of time to see if there's anything we need done there. (April '24); now by Sept '24, that same project has been bumped up to 2025.......and agency number 2 isn't ready.
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Finally, in narrower terms, looking at the discussion by
@turini2 ; You have lots of complex issues with being more ambitious; budget is among them for everyone. Building over another asset adds costs to asset number one, whose paying? The lawyers need to sort out strata issues. (The TTC still owns the bus terminal, but would now share certain infrastructure in common with any building over the top........that does make for complications.
To be clear, I'm all in favour of more civic ambition, but it requires the budget, staff hired for ambition, and who are encouraged to be bold and excel, and it requires lead time, lots of it. It can and should be done.........but it often isn't.