The Road as Instrument: How America's Highways Inherited Rome's Most Useful Lesson

The Roman road was an engineering marvel, and historians have spent considerable energy admiring it as such. The layered construction, the precise gradients, the milestone system that made the empire legible at a glance—these are genuinely impressive achievements, and they deserve the attention they receive. What deserves equal attention, and receives considerably less, is the frank acknowledgment by Roman administrators themselves that roads were built to move armies, not merchants. Commerce was a welcome secondary benefit. Control was the primary objective.

This distinction matters because it changes the interpretive frame through which we examine every road network that followed, including the one that reshaped American cities in the second half of the twentieth century. The Interstate Highway System is typically discussed as an infrastructure achievement, an economic catalyst, and—in its darker chapters—an inadvertent cause of urban disruption. The historical record suggests the disruption was rarely inadvertent. The road, across five thousand years of recorded use, has been among the most reliable instruments of power that any governing body has ever deployed. Understanding it as anything less is a choice, and it is not a choice the road's designers have typically made.

What Rome Actually Built and Why

The via militaris—the military road—was the foundational category of Roman road construction. The legions built them, maintained them, and used them to reach the edges of the empire within predictable timeframes. The famous calculation that a Roman army could cover twenty miles per day on a proper road was not incidental to imperial planning; it was the point. Rebellion in a distant province could be suppressed before it consolidated. Tax collection could be enforced. The physical fact of the road communicated, to every community it passed through, the nature of its relationship to Rome.

Routing decisions were political statements. Roads connected the places Rome wanted to connect and bypassed the places Rome wanted to isolate or diminish. The town that found itself on a major via gained access to markets, administrative attention, and the protective presence of passing troops. The town that found itself two days' walk from the nearest road learned, gradually and then permanently, what it meant to be peripheral. The engineers who made these routing decisions were not neutral technicians. They were instruments of a deliberate spatial politics.

Eisenhower's Stated Rationale and Its Complications

Dwight Eisenhower's enthusiasm for a national highway system predated his presidency. He had traveled the Lincoln Highway as a young Army officer in 1919, covering the continent by convoy and cataloguing the inadequacy of American roads for military logistics. He had watched the German Autobahn function as a genuine strategic asset during the Second World War. When he signed the Federal Aid Highway Act in 1956, he framed it explicitly in terms of national defense—the highways needed to be wide enough and straight enough to land military aircraft if necessary, and they needed to connect population centers to evacuation routes in the event of nuclear attack.

The military rationale was genuine. It was also, like Rome's commercial rationale, incomplete. The system's routing decisions—made by state highway departments, federal engineers, and local political actors across hundreds of individual planning processes—reflected a set of priorities that had very little to do with moving troops and a great deal to do with reshaping the human geography of American cities.

Syracuse, Memphis, New Orleans: Three Case Studies in Deliberate Disruption

In Syracuse, New York, Interstate 81 was routed directly through the 15th Ward, a dense, economically functional Black neighborhood that city planners had identified as a slum—a designation applied with notable consistency to neighborhoods whose land was wanted for other purposes. Thousands of residents were displaced. The neighborhood did not recover. The elevated structure that replaced it created a physical barrier between downtown Syracuse and the surrounding city, accelerating the commercial decline of both. A reckoning is currently underway: the state of New York has committed to tearing down the elevated section of I-81 and replacing it with a street-level boulevard, a process that has reopened every argument about what the original construction was actually for.

In Memphis, Interstate 40 was initially planned to run through Overton Park, a beloved public green space in a predominantly white, middle-class neighborhood. Residents organized, litigated, and ultimately won—the Supreme Court's 1971 decision in Citizens to Preserve Overton Park v. Volpe remains a landmark in environmental and administrative law. The highway was rerouted. What the legal record shows, and what the Memphis case makes difficult to ignore, is that the routing of highways through parks and green spaces in white neighborhoods was consistently reversed when residents had the political and financial resources to contest it. The routing of highways through Black neighborhoods was not.

New Orleans offers the most visually dramatic example. The Claiborne Avenue corridor, once the commercial and cultural spine of the city's Black Creole community, was bisected by the elevated Interstate 10 in the late 1960s. The live oak trees that had lined the neutral ground were removed. The street life that had organized itself around them—the second lines, the neighborhood commerce, the social infrastructure that made the corridor function—was severed by a concrete structure that cast the remaining blocks in permanent shadow. The Lower Ninth Ward's vulnerability during Hurricane Katrina in 2005 was not unrelated to decades of disinvestment that the highway's construction had accelerated.

The Feature, Not the Bug

The argument that these outcomes were unintended requires ignoring a substantial documentary record. Robert Moses, whose influence on American highway planning extended well beyond New York, was explicit in his preference for routing expressways through neighborhoods he considered expendable. Federal highway administrators received reports, throughout the 1950s and 1960s, documenting the demographic patterns of displacement. Urban renewal programs—which frequently cleared land that highway projects then occupied—were described by their own administrators, in internal documents, as tools for managing the spatial distribution of Black populations in American cities.

None of this required a single coordinating conspiracy. It required only that the people making routing decisions shared a set of assumptions about which communities mattered and which ones could absorb disruption—assumptions that were so widely held as to require no particular articulation. The Roman road engineer did not need to explain why the road bypassed a troublesome Gallic settlement. The logic was institutional, and institutions carry their assumptions in their procedures rather than their stated policies.

What the Road Reveals

The historical value of examining roads—Roman or American—is not primarily in cataloguing their abuses, though the catalogue is important. It is in recognizing that the road is always a theory of society made physical. It encodes a set of decisions about who moves and who stays, who is connected and who is isolated, whose neighborhood is a destination and whose is an obstacle to be cleared.

Those decisions are made by human beings who are subject to the same psychological pressures, the same institutional incentives, and the same capacity for motivated reasoning that have characterized every exercise of power in the historical record. The road does not lie about this, if you are willing to read it. The routes it takes, the neighborhoods it bisects, the communities it elevates to interchange status and the ones it leaves without an exit—these are primary sources. They tell you, with considerable precision, what a society believed about itself at the moment it poured the concrete.

History, examined honestly, has never stopped offering this lesson. The question is whether the people building the next road are willing to receive it.