High-traffic roads serve as a framework for new development in the United States, but noise and air pollution from cars and trucks negatively affect surrounding neighborhoods. We review how zoning policies have historically concentrated multifamily housing along busy roads and then evaluate three questions related to contemporary housing and transportation development.

First, do zoning policies disproportionately allow for high-density housing, as compared with low-density housing, near major roads? Second, does construction of high-density housing—specifically, affordable housing projects—occur disproportionately near major roads? Third, does major road construction lead to housing development, or vice versa?

Leveraging local and national data, we show the intimate connections between roadway construction, land-use policy, and housing types. We demonstrate that both zoning for and development of apartments is more common near busy roads. We then establish that the completion of new housing units is associated with subsequent highway construction and that new highways can accelerate preexisting development trends.

These results suggest that apartment buildings and their residents are, on average, much more exposed to pollution generated by busy roadways and that ongoing planning paradigms contribute to this outcome.