Where does adaptation to innovation take place? I present evidence on the role of agglomeration economies in the application of new knowledge to production. All else equal, workers are more likely to be observed in new work in locations initially dense in college graduates and industry variety. This pattern is consistent with economies from the geographic concentration of factors and markets related to technological adaptation. A main contribution is a new measure, based on revisions to occupation classifications, that characterizes cross-sectional differences across cities in technological adaptation. Worker-level results also provide new evidence on the skill bias of recent innovations.

Why do freeways affect spatial structure? We identify and quantify the local disamenity effects of freeways. Freeways cause slower growth in central neighborhoods (where local disamenities exceed regional accessibility benefits) compared with outlying neighborhoods (where access benefits exceed disamenities). A quantitative model calibrated to Chicago attributes one-third of the effect of freeways on central-city decline to reduced quality of life. Barrier effects are a major factor in the disamenity value of a freeway. Local disamenities from freeways, as opposed to their regional accessibility benefits, had large effects on the spatial structure of cities, suburbanization, and welfare.

We study the unintended effects of Fair Access to Insurance Requirements (FAIR) plans developed by 26 states in the 1960s to address insurance redlining in urban neighborhoods. FAIR plans’ problematic features included prohibitions on considering environmental hazards in underwriting, mandatory insurer participation in pools that diluted underwriting incentives, and payouts exceeding market values in declining areas. Using a triple-difference design comparing pre/post-FAIR periods, neighborhoods with/without likely FAIR access, and participating/non-participating states, we find that FAIR inadvertently led to significant housing disinvestment and accelerated declines in neighborhood population, with simultaneous increases in the Black population share.

Does social distancing harm innovation? We estimate the effect of nonpharmaceutical interventions (NPIs)—policies that restrict interactions in an attempt to slow the spread of disease—on local invention. We construct a panel of issued patents and NPIs adopted by 50 large U.S. cities during the 1918 flu pandemic. Difference-in-differences estimates show that cities adopting longer NPIs did not experience a decline in patenting during the pandemic relative to short-NPI cities, and they recorded higher patenting afterward. Rather than reduce local invention by restricting localized knowledge spillovers, NPIs adopted during the pandemic may have preserved other inventive factors.