Walsh and two other urban economists investigated zoning’s long-term effects in Chicago, using 1920s parcel-level data on land use and market values prior to, and immediately after, the adoption of the city’s first comprehensive zoning ordinance in 1923. They compared these early quilts of land use to that of the present day (or, at least, to the most recent complete dataset available, which came from 2005).
Contrary to what many economists may believe, they first found that zoning did not merely ratify existing land uses. Lot by lot, they found significant variation between the activities that predated zoning and those that came after, especially as years went by. For example, some factories and shopping areas that didn’t conform to the 1923 code were allowed to stay in their respective locations, thanks to a “grandfather” clause. But over time, the vast majority of them disappeared. The powerful force of zoning can be seen on a citywide scale, too: Whereas 82 percent of Chicago’s developed blocks had some form of commerce happening in 1922, that share had dropped by about half by 2005, researchers found.
In other words, the way Chicago looks in the 21st century tracks much more closely with the desires of its planners in 1923 than it does with the city that preceded zoning. This fact has had a huge effect on economic patterns, too. For example, the researchers found that exclusive residential zoning had a significant impact on home prices, driving up values in neighborhoods cordoned off for single-family homes. On a citywide level, they used a regression analysis to find that the zoning code of 1923 had bigger role in shaping economic patterns—i.e., where commercial and industrial activity is going on today—than either pre-existing transportation networks or geography, two factors you might think would best explain why there’s a factory by the old railroad tracks, or a shopping district near downtown…
Although the present paper didn’t explicitly analyze how Chicago’s old zoning codes have influenced racial segregation, a companion paper published in Julyby the same researchers found that the laws drawn up in 1923 were discriminatory: Areas with more black residents were zoned for higher-density housing, and “neighborhoods with larger populations of blacks or recent immigrants were zoned disproportionately for manufacturing.” Chicago consistently ranks as among the most segregated cities in the U.S., and its present-day economic divisions track closely with race (as well as with municipally recognized community boundaries). It wouldn’t be surprising to learn that zoning laws (much like housing policy) dating back a century are in some ways responsible. That’s a theory that needs investigation, Walsh says.
Zoning decisions are political ones. The suggestion here is that if the decisions are good ones, they can have positive effects for decades. The converse – particularly when used to limit options for particular groups – is also true.
The last paragraph of the article hints at recent suggestions regarding significant changes to urban zoning. It would be interesting to see what average Americans think of such ideas: would they trade predictability for flexibility? Continue with the example of Chicago: would more flexible zoning allow for the construction of more affordable housing or would it mean that more land would be converted to non-residential uses, limiting housing options? New Urbanists have touted mixed-use zoning for a long time but their vision of this is often limited to particular kinds of businesses or offices as well as nicer housing (even if it includes different price ranges).