Megaprojects are inherently unsuccessful …

Because we don't remember them as megaprojects if they work

Megaprojects get a bit of a bad name.

We often hear about disastrous megaprojects with high costs, delays, and failures to meet demand projections. I’d argue that part of the reason for this is that we only remember the unsuccessful ones or the recent ones that were delivered poorly. When you think of a megaproject, it might be something like Montreal Mirabel Airport, Athen’s Olympic facilities, or Boston’s Big Dig. We remember these because they’re standing there underused or they were the cause of recent controversy; a successful megaproject, or even one that happened just long enough ago that its construction travails are forgotten, becomes largely-ignored but essential infrastructure. Our attitudes toward megaprojects are largely coloured by survivor bias: once a megaproject is successful, it becomes invisible, but everybody notices that white elephant airport or transit line few people use.

Mirabel Airport terminal before its demolition. Image by Yvan Leduc.

For every Mirabel — Montreal’s underused jetport that no longer sees any passengers — there are dozens of Hartsfield-Jackson Atlantas or Munich Airports whose immense infrastructure is extremely useful. These projects were no less “mega,” but their great success means that complaints about them are more about overcrowding than project delivery or high cost. Paris’ RER, which I wrote about recently, was deeply controversial for its high costs. The expenses put immense strain on the region’s budgets, forcing more efficient approaches, a dedicated tax, and some compromises one might wish could have been avoided, like the shared RER B and D tunnels.

But today, those budgetary challenges are long since forgotten and nobody could imagine the Paris region functioning without the RER. Even the negative memories of Boston’s Big Dig are starting to fade and people are generally pleased that they have a long park through the centre of the city rather than the Green Monster.

The same is true for countless megaprojects across the world. Projects don’t get much more “mega” than the Delaware River Aqueduct. Begun in the 1930s, for decades it was the longest tunnel in the world. The cost was a major burden on the City of New York’s budget. Yet, does anyone even think about its existence when they turn on a shower in New York City? That megaproject provides the water that makes today’s New York City possible. No matter how much it cost, its benefits are incalculable.

New York’s Sixth Avenue Subway was ruinously expensive and complex to build in the 1930s. But does anybody worry about that today? The Beauharnois hydroelectric complex outside Montreal was a scandal that brought down a government. A century later, it remains a hugely important generating station that provides steady emissions-free power for a fraction of a cent per kilowatt-hour. The original American and Canadian transcontinental railways also resulted in huge costs and government-shaking scandal, but both countries could scarcely exist without them. Dallas-Fort Worth airport, which took forever to build and cost a fortune, is now one of the busiest airports in the world and a critical economic anchor for the whole state. The Jubilee Line Extension in London was delayed, far over budget, and nearly cancelled; a couple decades after its opening, it has become the essential link to many of the city’s fastest growing neighbourhoods. No doubt in Ancient Rome, there was someone in a toga complaining about the cost / benefit of a road that we still use two thousand years later.

The immense and sprawling Dallas-Fort Worth International Airport took many years to complete. Image by Tom Walsh.

This is another fundamental point about major infrastructure: it often functions far longer than we are accustomed to planning for and enables things we couldn't imagine. Hydro infrastructure in Quebec now powers AI inference and electric cars, things which were not even a glimmer in some planner’s eye when the concrete was being poured. Financial calculations of cost and benefit generally only look up to about 30 years out. Likewise, demand projections rarely even try to calculate more than a few decades. It’s easy to imagine the builders of the original London Underground worrying about meeting demand projections in year one and two, and how they were going to pay the interest on their bonds. It would not have even occurred to them to think that those tunnels would be carrying hundreds of thousands of passengers per day a century and a half hence.

The point of this argument is that short-term debates about infrastructure often miss that it usually has a life much, much longer than what we are comfortable planning for. That’s not to say that cost doesn’t matter; if it prevents us from building a project in the first place, or requires us to make serious compromises, the longevity of big infrastructure means those choices can haunt us for decades or more. And there are some projects that are genuinely ill-conceived, like Mirabel Airport where splitting domestic and international flights between two airports killed the connecting traffic that is essential for any major airport. But deciding whether to build infrastructure that will last a century or more based on the construction period or the first few years of operation is usually a big mistake. We should build intelligently and as cost-effectively as possible, certainly, but we shouldn’t let bad experiences discourage us from building the big infrastructure that is the basis of our modern civilization.