experience + careful planning + modularity

Think slow, act fast. (Plan it all out before you start digging tunnels)

The empire state building architects knew exactly how many rivets would be needed in total before they started. The building went up on time, under budget, about one story per day

Data on megaprojects is extremely unreliable fyi. Everyone involved has incentives to make it look better

It's not just transportation infra projects, it's everything. IT projects are even worse, despite presumably being more nimble and flexible

Avg cost overrun: 62%

But some have really fat tails and go way way over

This makes sense. Everything is interconnected and tightly coupled, and failures cascade

The longer a project takes the greater the risk that changing circumstances stimy it, which then is a positive feedback loop

Be fast.

But don't rush. Haste makes waste, and also shoddy work can kill a project (or worse, people)

Planning is cheap! Once you start production, delays, unknowns, and other issues are way more expensive! And you've sink way more cost at that point too!