In his magisterial, improbably thrilling 1989 book The Pencil, Henry Petroski, a longtime professor of engineering and historian at Duke University, recounted that Henry David Thoreau, upon making a list of essential items to bring on an expedition into the woods, neglected to mention a crucial item, something that he was actually never without: a pencil. “Perhaps the very object with which he may have been drafting his list was too close to him,” Petroski suggests, “too familiar a part of his own everyday outfit, too integral a part of his livelihood, too common a thing for him to think to mention.”

We overlook the things that are within reach, until they are not. That this would happen with small, common, or easily replaced objects is understandable, even rational. And yet we also tend to overlook those things that are large, expensive, and central to our everyday lives. I am talking here about infrastructure. Our awareness of road networks flickers to life only when a typical commute is congested with other drivers or closed for construction—indeed, this sort of “glitch in the matrix” stirred me to write my own book on the ubiquitous, yet neglected topic of traffic—in the same way our consciousness of the complexity and expanse of the modern commercial aviation system is awoken by extensive flight delays.

If Petroski, in The Pencil, wanted to elevate the humble writing instrument as a pocket marvel of engineering, the seeming goal of his new book, The Road Taken, is less to extol the infrastructure around us as a pantheon of mechanical achievement—a subject covered in his 1995 book, Engineers of Dreams: Great Bridge Builders and the Spanning of America—as it is to remind us, with a certain urgency, that it is there. The word “infrastructure” itself, he notes, is an early twentieth-century invention; it only began to appear in language in earnest in the 1980s. As a concept, infrastructure is a bit muzzy—it can encompass almost everything from the moment you leave your front door, sidewalk to cell tower. It is the atmosphere of the built world.

“We tend to be oblivious to much of our infrastructure, even when it is in plain sight, until something goes wrong with it,” Petroski writes in The Road Taken. The engineering profession itself, he notes, has not been immune from this tendency. The American Society of Civil Engineers, the group that issues a report card for America’s infrastructure every four years, did not include “levees” as a category until 2009, four years after Hurricane Katrina, when they received an aggregate D-minus. (The United States, Petroski writes, is like a “poor student” who never learns his lessons.) Infrastructure in America seems to be the perennial barn door that’s closed after the horses have gone. We are hardly alone; substantive flood-control projects in the Netherlands and England only got going after disastrous floods in the middle part of the twentieth century. But there may be, Petroski hints, something in the American character, the impromptu pragmatism of a settler nation, that emphasizes the quick fix, what one historian called “the self-fulfilling perception that rapid innovation would quickly render current designs obsolete.” And given the wider societal lack of interest in infrastructure, small wonder there should be little political capital to be had in pushing for costly repairs or expanded maintenance. Today, politicians might be glad to show up and grab golden shovels for a bright new project, but pushing through tax increases for bridge inspections—or to guard against some vaguely predicted future event—does not make for good optics.


As an interest group, we might expect a certain amount of grade inflation—or, in this case, deflation—from the ASCE; proclaiming the country’s infrastructure to be in decent working order is not likely, after all, to generate much work for engineers. But it does not take a vested interest to sense that America, whose roads and rails were once the envy of the developed world, has somehow gone astray.

To take New York City—where I live and where Petroski grew up—as an example, despite being constantly told I live in the center of the world, when it comes to infrastructure, I am constantly wishing I were elsewhere. When the subway comes screeching along, tinnitus on braking metal, I long for the silent rubber tires used by trains in Mexico City or Montreal. When I salmon against the crushing stream of pedestrian and bicycle traffic on the stingy walkway of the Brooklyn Bridge, I long for Brisbane’s capacious, car-free Kurilpa Bridge. Flying into any Gotham airport, the convenient, legible urban transport links one finds in Amsterdam or Geneva are absent. There are cities in Kansas, thanks to Google Fiber, that currently have better bandwidth than the nation’s media capital. Growing up in Brooklyn, many decades ago, Petroski notes that he and his childhood friends would occasionally go down the hill, from Park Slope, until they ran into the Gowanus Canal, “stagnant and odorous.” In 2016, the canal is still stagnant and odorous, an EPA Superfund site, even as glassy luxury condos rise on its fetid banks.

“America,” argues Petroski, gleaning a hoary image from Robert Frost, “is now at a fork in the road representing choices that must be made regarding the nation’s infrastructure.” But, Petroski being Petroski, he wants to map for us, with breadth and exacting detail, all the previous forks in the road which brought us to where we are; how, for example, choices made along the development of our road networks have led to where we are today—literal path dependence. This is all done in a sometimes meandering, if nonetheless engaging way, flitting through varying historical periods, moving at scales that range from Olympian bridge projects to the most mundane bits of pavement markings. Who else but Petroski would connect the decline in quality of the once-reliable woodworking planer in his toolbox (now made in China) with deficient Chinese-welded steel on San Francisco’s Bay Bridge?

Frost’s road imagery is not idly chosen, for roads (with bridges a strong second) seem to be the symbolic heart of the book—and they are what many of us, in driving-heavy America, probably most immediately regard as infrastructure. Perhaps the most salient fact about American roads today is that almost all of them are asphalt, “94 percent of the more than two million miles of paved roads in the United States,” Petroski notes. The second is that it always seems they are being repaved. I was once told by a state transportation official at a conference about a highway firm in Texas that basically made its living by perpetually repaving one long stretch of highway; when employees finished in one direction, months if not years later, they simply turned around and started work on the other side.

Asphalt, notes Petroski, long known as an adhesive, was first employed as a road surfacing through accident: A nineteenth-century Swiss engineer happened to observe carts carrying rock bitumen lose some of their cargo. “These fell into depressions and ruts in the road,” notes Petroski, “and when compacted by traffic made for a better road.” Whether, ultimately, they made the best road is one of those twisting tales Petroski wants to unravel; as he notes, “still, the question of concrete or asphalt was hotly debated through the 1920s and 1930s.” Actually, it is still being debated: The magazine Public Works in 2012, for example, ran an article breathlessly headlined “Asphalt Vs. Concrete: The Fight to Pave Our Roads.”

Items spilling from wagons seem to be a curious theme in the history of road infrastructure. Petroski recounts the wonderful, verging on apocryphal story of a Michigan road official who in 1911 “observed a milk wagon leaking some of its contents and leaving a white stripe behind it as it progressed down the road.” Hence the modern centerline was born, the first one painted near Detroit; a magazine called it “the most important single traffic-safety device in the history of auto transportation,” a claim that, while spirited, is almost certainly false. Before this and for a while after, Petroski notes, automobiles traveled down “unadorned” roads, simply hugging their side of the street. Of course, lines don’t do much to keep the drowsy or distracted driver from crossing over them, hence the emergence of guardrails or “Jersey barriers,” concrete dividers that, Petroski notes, despite their name actually debuted in California. Even this seemingly banal piece of infrastructure, Petroski observes, has a secret design history and a taxonomy of variants, its very shape evolving the more engineers learned what happened after cars struck it. Similar stories abound: Why is the stop sign octagonal? Should those highway centerlines be white or yellow? Were green highway signs better than the blue ones used by New York’s Thruway Authority?

The inescapable sense one draws from The Road Taken is that infrastructure is hard. When the new East Bay portion of the San Francisco Bay Bridge was unveiled, “its top was found to be 18 inches closer than its bottom to the East Bay shore.” Steel cables were attached to “stretch” the tower back into correct position; the rods, however, did not simply stretch, but began to microscopically crack, making it difficult to predict future earthquake response—which, writes Petroski, “essentially nullified the whole point of building the new bridge in the first place.” Even more humble projects can present a raft of outsize problems: In 2013, New York’s pedestrian-only Squibb Park Bridge, designed by the prominent engineer Ted Zoli, provided a delightfully bouncy shortcut from Brooklyn Heights down into Brooklyn Bridge Park. A little more than a year later, however, some unforeseen structural hazard made the bridge too bouncy, and it was closed with no date set to reopen.

But perhaps more intractably, infrastructure is politically hard. Petroski quotes an early proponent of roads who said that highways are “built chiefly of politics” instead of proper materials like “crushed rock or concrete.” The Tappan Zee Bridge, in New York’s Hudson Valley, notes Petroski, was built at one of the Hudson River’s widest points, only adding to the technical challenge. Why? So it could be located outside the political influence of the Port Authority, which has control of any bridge project within 25 miles of New York City. “Like a good movie,” writes Petroski, “the drama of the aging bridge across the Hudson River has elements of intrigue, suspense, and hidden agendas.” It’s Chinatown, Jake.

To return to the idea that we don’t really notice infrastructure until it fails, the way this is expressed politically is that no one seems to want to pay for infrastructure until it fails. The annual replenishment of the Highway Trust Fund resembles an elaborate pyramid marketing scheme, with legislators desperately looking to tap any number of obscure funding sources, rather than actually charging the users of the roads. To wit, the federal gas tax—18.4 cents per gallon of gasoline, 24.4 cents per gallon of diesel—has not been raised since the Clinton administration, not even to keep up with inflation. In states like New Jersey, as Petroski notes, the entirety of the gas tax pays the interest on the debt of previous infrastructure projects.

The real crisis in this regard is less the need to build new infrastructure than simply paying for the upkeep of the one we have. As the writer Alex Marshall has noted in Governing magazine, most states and cities cannot borrow to fund maintenance projects, they can only use operating budgets, which are prone to be raided to fill budget shortfalls elsewhere; hence, maintenance projects are chronically underfunded. But the inescapable law of infrastructure, as Petroski reminds us, is that “using it means wearing it out.” The problem with this malign neglect is that, like a pothole that forms on a New York City street after a particularly harsh winter and is left alone, problems only get larger: The dollar that is not spent today to maintain a road becomes four or five dollars a few years later.

Petroski argues with passion and conviction for the restoration of our infrastructure—and the restoration of its centrality to public life. At times, however, Petroski seems to suffer from some of the tunnel vision of transportation engineers themselves: He is quite good at solving the problems he is asked to solve, but not often as good at seeing past the parameters of the solution. On several occasions, he trots out the familiar specter of the societal cost of congestion, the implication being that it can be overcome by simply building more infrastructure. Apart from the methodological issues with actually assigning costs to congestion—the “costs” are drawn against a fantasy metropolis where every single-occupant vehicle can move at or close to free-flow traffic speeds at peak hours—there is the problematic assumption that the response to congestion is infrastructural rather than, say, economic. Surely, this thinking goes, a more efficient orientation of roads could overcome the undesirable charging of a population for scarce resources like parking.

Petroski’s fixation on potholes raises the question of how to prioritize infrastructure spending. Potholes may be an infrastructural problem, but what honestly looms larger when it comes to my local streets is being able to cross them safely with my young daughter. In this regard, cities like New York have lately been responding to another kind of infrastructural crisis—that streets built in previous decades, under the prevailing wisdom of engineers, presented systemic hazards to those not in cars. The infrastructure may not be structurally deficient, but it is socially deficient.

The Road Taken comes at an interesting time, when, as Adam Rogers recently argued in Wired, the idea of infrastructure is being eclipsed—or at least augmented—by what he calls a “metastructure.” It is not simply a question of building more roads, or more storage capacity for vehicles that mostly sit idle, but building vehicles that can handle those roads more efficiently, or using networked intelligence to more efficiently distribute users (like packets of data) across all kinds of existing transport infrastructure; in this regard perhaps the most exciting transportation technology of the twenty-first-century is the smartphone. Of course, even the iPhone-summoned self-driving Uber car, routed to you via the wisdom of crowds directed by Waze, will have to ply old-school—sometimes nineteenth-century old—infrastructure. Sometimes, the bridge to tomorrow really is a bridge.