Research

Works in Progress

Divided Highways: Historical Determinants of Highway Placement

The United States Interstate Highway System (IHS) was the result of massive levels of investment and planning by states and the federal government in the mid-20th century. The connectivity provided by the IHS was a major boon to economic activity; at the same time, construction of the urban segments led to destruction of homes, division of communities, and increased exposure to pollution. Given the scale and expense of the project, property values were a driving factor behind highway placement in urban areas. However, there is qualitative evidence that many planners saw highway construction as an opportunity to remove unwanted, namely Black, populations from the city center. Existing research finds that urban segments of the IHS were disproportionately placed through neighborhoods whose populations were mostly Black, but the high correlation between race and property values at the time makes it difficult to isolate causal effects. I approach this problem by developing an identification strategy that utilizes existing patterns in zoning and highway placement and interprets deviations from those patterns as the effect of race on highway placement. Understanding the role of race in highway placement is vital to understanding the foundation of one of the United States' most significant infrastructure projects.