There’s a preliminary paper circulating at Brookings, looking at American infrastructure construction costs. Authors Leah Brooks and Zachary Liscow have tabulated the real costs of the American Interstate program over time, from the 1950s to the 1990s, and find that they increased from $5.3 million per km ($8.5 million/mile) in 1958-63 to $21.3 million/km ($34.25 million/mile) in 1988-93.
Moreover, they have some controls for road difficulty, expressed in slope (though not, I believe, in tunnel quantity), urbanization, and river and wetland crossings, and those barely change the overall picture. They go over several different explanations for high American infrastructure costs, and find most of them either directly contradicted by their results or at best not affirmed by them.
I urge readers to read the entire paper. It is long, but very readable, and it is easy to skip the statistical model and go over the narrative, including favored and disfavored explanations, and then poke at the graphs and tables. I’m going to summarize some of their explanations, but add some important context from cross-national comparisons.
Why costs (probably) aren’t rising
The authors identify four hypotheses they rule out using their research, in pp. 19-23 (they say five but only list four):
Difficult segments postponed and built later – they have some controls for that, as mentioned above. The controls are imperfect, but the maps depicted on pp. 59-61 for the Interstate network’s buildout by decade don’t scream “the segments built after 1970 were harder than those built before.”
Time-invariant features – these include cross-national comparisons, since the United States has always been the United States. I will discuss this in a subsequent section, because two separate refinements of what I’ve seen from cross-national comparisons deal with this issue specifically.
Input prices – this is by far the longest explanation the authors deal with. Anecdotally, it’s the one I hear most often: “labor costs are rising.” What the authors show is that labor and materials costs did not rise much over the period in question. Construction worker wages actually peaked in real terms in 1973 and fell thereafter; materials costs jumped in the aftermath of the oil crisis, but came down later, and were back at pre-crisis levels by the 1990s (p. 48). Land costs did rise and have kept rising, but over the entire period, only 17.7% of total costs were preliminary engineering and land acquisition, and the rest were in construction.
Higher standards – the authors looked and did not find changes in standards leading to more extensive construction.
There are several more incorrect explanations that jump from the data. I was surprised to learn that throughout the 1970s and 80s, completion time remained mostly steady at 3-3.5 years of construction; thus, delays in construction cannot be the explanation, though delays in planning and engineering can be.
The authors themselves list additional explanations that have limited evidence but are not ruled out completely from their data, on pp. 32-35. Construction industry market concentration may be an explanation, but so far data is lacking. Government fragmentation, measured in total number of governments per capita, has no effect on the result (for example, California has high costs and not much municipal fragmentation); I’ll add that Europe’s most municipally fragmented country, France, has middle-of-the-road subway construction costs. State government quality, as measured by corruption convictions, has little explanatory power – and as with fragmentation, I’ll add that in Europe we do not see higher costs in states with well-known problems of clientelism and corruption, like Italy and Greece. Work rules requiring the addition of more workers may be relevant, but unionization and left-right politics are not explanatory variables (and this also holds for rail costs).
Economies of scale look irrelevant as well: there is negative correlation between costs and construction, but the causality could well go the other way. Finally, soft budget constraints are unlikely, as the federal government can punish states that mismanage projects and take more money; it’s possible that as the Interstate program ended states felt less constrained because there wouldn’t be money in the future either way (“end of repeated game”), but the fact that costs keep rising in subway construction suggests this is not relevant.
Two explanations stand out to the authors. The first is that nearly the entire increase in construction costs over time can be attributed to a mix of higher real incomes and higher house prices. While the construction workers themselves did not see their wages rise in the late 1970s and 80s, a richer population may demand more highways, no matter the cost.
Higher real estate costs could have an impact disproportionate to the share of land acquisition in overall costs by forcing various mitigations that the paper does not control for, such as sound walls and tunnels, or by sending roads over higher-cost alignments.
The second explanation is what the authors call citizen voice. Regulatory changes in the 1960s and early 70s gave organized local groups greater ability to raise objections to planning and force changes, reducing community impact at the cost of higher monetary expenditures. The authors give an example from suburban Detroit, where a highway segment that disrupted a Jewish community center took 25 years to be built as a result of litigation.
The authors don’t say this explicitly, but the two explanations interact well together. The citizen voice is very locally NIMBY but is also pro-road outside a handful of rich urban neighborhoods. Higher incomes may have led to public acceptance of higher costs, but local empowerment through citizen voice is the mechanism through which people can express their preference for higher costs over construction inconvenience.
How time-invariant are national features, anyway?
The authors contrast two proposed explanations – higher incomes and property values, and stronger NIMBY empowerment – with what they call time-invariant features, which could not explain an increase in costs. But can’t they?
I spent years plugging the theory that common law correlates with high subway construction costs, and it does in the developed world, but upon looking at more data from developing countries as well as from before the last 25 years, I stopped believing in that theory. It started when I saw a datapoint for Indonesia, a civil-law country, but even then it took me a few more years to look systematically enough, not to mention to wait for more civil-law third-world countries to build subways, like Vietnam. By last year I was giving counterexamples, including Montreal, low rail electrification costs in some common law countries, and the lack of a London cost premium over Paris until the late 20th century.
In lieu of common law, what I use to explain high costs in the US relative to the rest of the world, and to some extent also in most first-world common law countries as well as third-world former colonies, is weak civil service. In the developed world, the theory behind this is called adversarial legalism, as analyzed by Robert Kagan. Adversarial legalism enforces the law through litigation, leading to a web of consent decrees. Some are naked power grabs: for example, in Los Angeles, a union sued a rolling stock vendor for environmental remediation and agreed to drop the lawsuit in exchange for a pledge that its factory be unionized, which may play a role in why the trains cost around 50% more than equivalent European products.
American litigiousness developed specifically in the 1970s – it’s exactly how what the authors of the paper call citizen voice is enforced. In contrast, on this side of the Channel, and to some extent even generally on this side of the Pond, laws are enforced by regulators, tripartite labor-business-government meetings, ombudsmen, or street protests. French riotousness is legendary, but its ability to systematically change infrastructure is limited, since rioting imposes a real cost on the activist, namely the risk of arrest and backlash; in contrast, it is impossible to retaliate against people who launch frivolous lawsuits.
I bring up the fact that I said most of this last year, and the rest at the beginning of this year, whereas I was not aware of the paper under discussion until it was released a few hours ago, to make it clear that I’m not overfitting. This is something that I’ve been talking about for around a year now, and a jump in American construction costs in the 1970s and 80s – something that also looks to be the case in subway construction – is fully compatible with this theory.