Previous work on transportation investments has focused on average impacts in high- and middle-income countries. We estimate average and heterogeneous effects in a poor continent, Africa, using roads and cities data spanning 50 years in 39 countries. Using changes in market access due to distant...

Comprehensive zoning is ubiquitous in U.S. cities, yet we know surprisingly little about its long-run impacts. We provide the first attempt to measure the causal effect of land use regulation over the long term, using as our setting Chicago's first (1923) comprehensive zoning ordinance. Our...

We investigate the effect of subway system openings on urban air pollution. On average, particulate concentrations are unchanged by subway openings. For cities with higher initial pollution levels, subway openings reduce particulates by 4% in the area surrounding a city center. The effect decays...