This is a peer-reviewed paper in an engineering journal.
@allengeorge
Lots of things you (and I ) would disagree with are published in peer-reviewed journals. Many are wrong. Peer-review is often superficial and light, and examining only basic facts and rudimentary honesty.
It often fails to check the assumptions made, and whether the comparisons are valid.
This is a survey piece of other work, its not original.
And its very poorly done.
All people, no matter what their position, on any issue, must be prepared to treat research neutrally, and evaluate its quality on the merits.
That doesn't mean there isn't a legitimate point somewhere.
But this survey work is absolutely terrible to the point of being borderline worthless.
Here's the underlying paper:
I actually read it all, and I understand it.
The margins of uncertainty and the comparison of entirely unlike things measured in unlike ways exceeds credulity by an order of magnitude.
Let me quote:
"When considering the payback period of these 10 cases, there is an uncertainty up to 75%."
****
Of course tunneling is more intensive construction work than building on the surface....if all other things were equal (duh!)
But all other things are not equal, there is no weight allotted for all the carbon-intense structures that must be removed to allow for a new surface corridor, that wasn't measured.
Nor is there any understanding of displacement. By which I mean, if you build on the surface in a core, urbanized area.....that is growing...........where does the development that would have gone on the surface go instead?
If you build over the track, that is extremely carbon-intensive, and creates an above-ground tunnel, to what project is that being charged?
They expressly conflate unlike projects, HSR, Commuter Rail, Freight and Metro and compare rural, suburban and urban areas as if they were the same and blank slates. I would use the word preposterous to describe this conflation.
This is just very lazy work.
