Interestingly, the most expensive ones are almost always highway systems. Can someone briefly explain why? I'm my naive view it's mostly asphalt and terrain work.
Highway systems create massive economic benefits that are relatively simple to calculate, just in the raw # hours saved which massively increases productivity. This can be well captured by the state through taxes or (less frequently) by private industry through tolls - i.e. the people that direct their construction.
Other mega projects have much less certain benefits, or the benefits are harder to capture by those with the ability to allocate resources because incentives aren't sufficiently aligned.
Thus the question I have to the scientists pushing for a new LHC is: "What would we get from the journey?" If they truly believe in the project they'll have a dozen technologies that need to be developed to make their project happen, all of which have practical applications beyond their experiment. If they don't they'll just be pushing for "same but larger" which is IMO a waste of resources. Because why shouldn't we be investing in the technology to do "Same but smaller" in that case so we can do more with less?
I don't think one should even have to demonstrate "practical applications beyond the experiment" beforehand. Just that it is a complete problem that can be solved independently from the entire project.
If there are a lot of those, it's much better to fund those and get the results that will push the cost of the full thing down. Even if the total costs turn up to be higher than focusing on the collider from the start.
- It’s a lot of asphalt
- construction happens over a wide possibly remote area so all construction materials need transportation
- materials are probably made to order so you are buying effectively a lot of custom components
- engineering/architecture/construction talent isn’t cheap and there’s a lot of competing demand
- hiring is even more difficult as the job isn’t in one place may require a lot of travel, bed and board for all types of workers
- property itself is possible a significant cost to build it through. Even more if you get caught up in legal battles acquiring certain properties
- grift, with large projects in any country at any time there’s always grift. Grift is a constant
It’s labour, fuel, and material, intensive work.
Sometimes when they dig into the ground they find something unpredictable e.g. contaminated soil which can result in a major cost blowout, a legal fight between government and contractor and then unplanned delays which further increases costs.
Having to carry trucks for decades means a lot more steel and concrete. Especially when constructing bridges and overpasses.