Zoning

Zoning is a form of “indirect” urban design, as its rules and restrictions dictate what can be built on each parcel in most American cities. Though designers rarely write code themselves, zoning affects the urban form in many ways. Every road width and building height delivers a message to their users on how to use the public realm. In fact, zoning code is often written by engineers, who are trained in place-making in a very different fashion than designers.

Though most zoning only regulates general building dimension details, the mandated site use has a big impact on the building’s appearance. For example, if a lot is zoned for a single-family home, it will likely not have large ground-floor display windows and a block-long floor plate. Such limitations can be very constraining as use patterns change over time and sites need to be renovated and adapted in order to thrive in a new use.

Zoning code has evolved over the years as urban planning theory and political priorities have changed. Many old zoning codes are outdated and economically inefficient, and do not have the flexibility in their parcel-by-parcel designation to allow for smooth transitions to new land uses.

An entire rezoning is time-intensive and strictly adhering to outdated code can hinder development. Therefore, many cities loosen their amendment process to help landowners change the zoning code quickly, or simply ignoring the code and letting developers build structures that directly violate the ordinance. This explains the negative connotation surrounding the Philadelphia zoning code, which is so old that it is seen by many as a direct hindrance to progressive development that could help make the city a more world-class destination. Many developers see zoning here as an obstacle to overcome, not as standards that must be met to integrate into the surrounding community.

Many cities are experimenting with different zoning types. Some more flexible zoning forms include (1) form-based zoning, which regulates by design instead of use; (2) incentive zoning, which rewards developers for meeting certain urban design standards, and (3) performance zoning, which allows landowners to meet building goals by achieving various levels of compliance. Zoning is not used in all American cities. Houston is the largest U.S. metropolis without a zoning code in place, as citizens continue to reject efforts to implement it.

http://municipalcodes.lexisnexis.com/codes/philadelphia
http://citymaps.phila.gov/citymaps/
http://www.formbasedcodes.org/
http://scholar.lib.vt.edu/theses/available/etd-05122004-113700/unrestricted/BurdetteFINALmajorpaper.pdf
http://www.law.pace.edu/landuse/bincent.html
http://www.transcoalition.org/ia/incentzn/01.html