You might think that saves a lot of money, until you drive around Zürich (think: M25), and realise that about 80% of your drive was through tunnels... and Zürich is not even mountaneous.
Be more impressed if you said you were a civil engineer. Living in a house didn't tell me what makes them expensive.
So, Zürich: you remember the tunnel that comes out half way to Adliswil, under Uetliberg?
What did it cost as a tunnel, what would that have cost as a surface road in reality, and what would it have cost as a surface road if the area had been flat? *That* is why you're being called out by loads of people for "a smaller geographic footprint".
Are you talking about the A3? If I recall correctly, it was like CHF 1B? That’s at least 20X more per km than a surface road? but it’s also more than just a car tunnel.
As for call outs, who cares? Some people will find a reason to nag on any day that ends with a y.
You might think that saves a lot of money, until you drive around Zürich (think: M25), and realise that about 80% of your drive was through tunnels... and Zürich is not even mountaneous.