Seely on Nall, 'The Road to Inequality: How the Federal Highway Program Polarized America and Undermined Cities'

Clayton Nall
Bruce Seely

Clayton Nall. The Road to Inequality: How the Federal Highway Program Polarized America and Undermined Cities. Cambridge: Cambridge University Press, 2018. 170 pp. $99.99 (cloth), ISBN 978-1-108-41759-4.

Reviewed by Bruce Seely (Michigan Technological University) Published on H-FedHist (February, 2019) Commissioned by Caryn E. Neumann (Miami University of Ohio Regionals)

Printable Version:

Roads and highways have rarely attracted attention from social scientists, although most recognize that the American road network was a central element in the twentieth century’s automobile culture, and that Interstate highways in particular matter enormously to the economy, transportation, and American life and leisure. Thus scholarship on Interstate highways usually has focused on the system’s origins, development, and immediate consequences for urban landscapes, economic patterns, and residents.  

Political scientist Clayton Nall, however, approaches the Interstate program with a question not pursued by other researchers. He seeks to assess how the Interstate program affected American politics. In The Road to Inequality, Nall argues that the Interstate Highway System shaped the geography of the US political landscape after 1960 or so. This road network facilitated the movement of white middle- and upper-middle-class residents to suburbs and resulted in spatial and political sorting that underlies the polarization of contemporary American politics. His argument rests upon extensive spatial and statistical analysis of census and political survey data.

Nall’s book advances his thesis with four key arguments. First, Nall contends that Interstate roads, once constructed, provided a catalyst for movement to the suburbs. But that movement, he also contends, was never equal and that unevenness filtered who could take advantage of this opportunity. This pattern provided the foundation, he argues, for partisan geographic sorting. Second, Nall examines changes in the politics of metropolitan areas after 1950. Nall does this by comparing county-level voting patterns in suburban and urban precincts, with attention to the miles of Interstate highways in each county. He is able to track the emergence of Republican suburbs and Democratic cities.  He notes however, that this pattern is significantly stronger in southern states than in the Midwest or Northeast. 

Nall’s third point concerns the consequence of spatial and political sorting for transportation policy. He explores whether the resulting partisanship shaped policy outcomes. Nall makes interesting use of a collection of cross-sectional national surveys on transportation needs that began in the 1950s (Roper Center surveys and the General Social Survey). By mapping survey responses spatially, he finds that support for highways remained largely unchanged over time, while interest in public transit programs and subsidies for transit operations declined steadily in suburban areas. He attributes this shift in transportation preferences to partisanship.

In the last chapter, Nall considers whether this spatial variation in public opinion concerning roads versus public transit actually translated into changes in transportation policy. Interestingly, he finds little evidence that partisanship impacted national transportation policies. He argues that the status quo prevailed in the nation’s transportation programs, given consistent support from both Republicans and Democrats. But at the local, state, and regional levels Nall finds that partisanship has become much more apparent in the implementation of transportation policy. He notes correctly that the federalist nature of the nation’s road program, which requires significant sharing of funding and responsibility between federal and state actors, largely explains this situation. Metropolitan planning organizations (MPOs), created in the late 1960s to ensure a local voice in highway planning and programming, are a primary site for the partisanship Nall finds. Structurally, MPOS provided multiple suburban governments with votes, while the city administrations that handled most of the traffic had only one vote. Null notes that arrangement resulted in MPOs typically supporting suburban preferences for more roads while urban residents’ preferences for additional public transit prevailed less frequently. Partisan sorting, in other words, has shaped regional and local transportation policy choices.

In his conclusion, Nall addresses alternative explanations for the transportation policy outcomes he has identified. He examines whether race, gender, and economic status, among others, account for the policy choices. His argument is more careful than his title suggests, for he clearly recognizes a single cause cannot explain the current state of American politics. He carefully argues that the road system has facilitated, rather than caused, political partisanship. In the end, however, Nall assigns significant weight to the Interstate highway program in explaining the political polarization we observe in twenty-first-century America. He also argues that spatial analytic tools should be more widely adopted for understanding the operation of the American political system. 

I find his main conclusions persuasive, primarily because of his conclusions about differences between transportation policy implementation at the national and regional levels. From the start of the twentieth century until the late 1960s, the American road program was generally defined by the efforts of engineers at the state and federal levels who worked in concert to guide the nation’s road-building efforts. Congresses and presidents alike generally deferred to these experts, as both parties supported a consistent highway policy for decades. But the role of experts diminished sharply after the “freeway revolt” of the 1960s-70s, which included resistance to both urban Interstates and express highways in areas of scenic beauty. Metropolitan planning organizations, as well environmental impact statements, were examples of the steps taken to increase local influence in highway and transportation policy debates with technical experts. Nall’s account indicates that the “reforms” of the late 1960s and 1970s definitely brought transportation policy under the control of political actors at the regional level, as local suburban residents supporting highways triumphed over more populous urban voices seeking transit systems. I would suggest that the demise of national experts as arbiters of transportation policy is another significant factor that facilitated the emergence of political polarization. This insight shows the potential value of fitting Nall’s work more deeply into the longer history of American road development and policy.

One other point made by Nall deserves more attention—specifically, his finding that spatial and political sorting leading to partisanship best fits southern and Sun Belt states. He explores several reasons for this outcome, but I suggest the importance of recognizing that suburbs in the South and West were often products of postwar automobility, while older suburbs in the East and Midwest (Rust Belt) often traced their origins street car lines built after 1890. Other suburbs in those areas took shape after the 1945 but before the Interstate program; Levittown was the most famous example. This is not to say that these earlier suburbs were more likely to be diverse—either political or socioeconomically—than southern postwar suburbs. And it is true that Interstate-facilitated suburbs appeared in every part of the country as urban sections of the system reached cities, generally after 1960. Yet the different patterns of suburbanization and the less overt racial segregation of the Midwest and East may have mitigated some of the sorting that Nall finds so evident in the South. In other words, historical differences and regional variation may restrict the applicability of Nall’s argument to the entire country.

Further, even if we accept that Nall describes a national pattern of spatial and political sorting in the suburbs promoting political partisanship, one additional query might be posed. Nall focuses on “polarization” as a phenomenon of the past two decades or so. But the Interstate network was fundamentally built and many of those suburban tracts occupied before 1985. Why did the polarization he is exploring appear a decade and more later? As well, what about earlier periods of polarization, say, the 1960s, when suburban, well-off college students, men and increasing numbers of women, joined less privileged African Americans living in cities to demand an end to the war and civil rights?

These variations suggest an obvious conclusion: no single factor can explain the partisan patterns of current American politics. Further, Nall notes the difficulty of determining the motives behind the individual actions that maps present as aggregate data. Aggregations, as we know, can never completely explain the actions of individuals. Indeed, some personal choices may stem from reasons quite removed from patterns we discern in data. Explaining the motivations of people who moved to suburbs seems to me one such problem. Even with these concerns in mind, however, Nall’s use of geospatial, census, survey, and electoral data offers a promising tool for exploring American life and politics. His is a useful addition to the historical literature on the Interstates, for his political science approach opens a different way of examining the consequences of this federal infrastructure project. And there is no doubt that his book is timely in regard to the current politics of the country. Nall’s maps, for example, exhibit many features of the widely displayed red nation/blue nation maps adopted by news media analysts of electoral patterns since 2000. He may not offer an all-encompassing explanation, but Nall’s book is worthwhile reading, both for its insights concerning connections between Interstate highways to politics in United States.


Citation: Bruce Seely. Review of Nall, Clayton, The Road to Inequality: How the Federal Highway Program Polarized America and Undermined Cities. H-FedHist, H-Net Reviews. February, 2019. URL:

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