I feel like large multi-year construction costs have a tendency to increase significantly (outside of the normal increases in year-of-expenditure costs), and I wonder if this is because construction firms know something needs to be built and will behave accordingly.
This is in contrast to smaller projects, especially during recessions, where construction firms may be more likely to need the work (lower bids) and also don't have the expectation that the project will have to be completed (they can wait it out to extract more money from a contract).
This is in contrast to smaller projects, especially during recessions, where construction firms may be more likely to need the work (lower bids) and also don't have the expectation that the project will have to be completed (they can wait it out to extract more money from a contract).