This is one of a series of interviews by Bloomberg Opinion columnists on how to solve the world’s most pressing policy challenges. It has been edited for length and clarity.
Virginia Postrel: The lack of affordable housing in major US cities has impeded social mobility, fueled inflation and worsened economic inequality. You’re the author of a new book, “Arbitrary Lines,” which looks at the history of zoning and the role it’s played in the housing crisis. You emphasize that zoning is just one aspect of city planning. So, what is zoning?
M. Nolan Gray, author, “Arbitrary Lines: How Zoning Broke the American City and How to Fix It”: Zoning is trying to do two basic things. The first is to segregate land use into categories: residential, commercial and industrial. And within each of those categories, there are going to be dozens of subcategories. So, for example, in Los Angeles, there are residential districts where you can only have single-family homes; or there are residential districts where you can have small apartment buildings or larger apartment buildings. Within commercial zones, there are areas where you can have offices, others where you can have retail.