We propose a theory-inspired measure of the accessibility of a city's center: the size of the surrounding area from which it can be reached within a specific time. Using publicly available optimal-routing software, we compute these "accessibility zones" for the 109 largest US and European...

During the nineteenth century the United States urbanized - the share of the population living in urban areas increased - and industrialized - the share of the labor force in manufacturing increased. Our survey of the literature and analyses of census data suggests that a key reason was the...