Traditional Zoning Can't Meet the Challenge of Modern Development

Among the innovations championed by the New Urbanist or neo-traditional movement, and by many other architects and planners, are "form-based" zoning codes.

The primary goal of form-based codes is to guide the configuration and architectural quality of urban and suburban environments. That contrasts with conventional zoning, which often concentrates on the use of buildings, such as whether a block is residential or commercial.

Judging from the aesthetic dysfunction in much of what we have built, form-based codes are long overdue.

Actually, we should eliminate the term zoning. It implies separation, exclusion and disconnection, and it suggests nothing positive about how neighborhoods and buildings should look or relate to each other.

In Houston, a city without zoning, the term is taboo. In a recent report recommending new housing strategies for the city, I wrote that, in America, "planning is not zoning, and zoning is not planning. Conventional zoning generally has failed as an effective planning tool for creating balanced growth, good urban design, beautiful cityscapes, or affordable housing. In many jurisdictions, the effect of zoning has been to exclude the less affluent."

To further convince Houstonians of the merits of planning and land-use regulation, the report went on to state that "unconstrained by conventional zoning regulations, Houston has a unique opportunity that no other American city has: it can undertake effective planning not trumped or compromised by existing zoning."

Conventional zoning ordinances divide a municipality or county into zones, define and designate the land use for each zone and stipulate for each zone and zoning category maximum densities and building heights, maximum lot coverage and minimum setback, yard and lot dimensions. Zoning regulations also often require minimum parking accommodations.

Historically, the purpose of zoning has been less as an urban design tool and more as a way to protect public health, safety and welfare, and private property values. Zoning presumably maps the future. Yet for many property owners, zoning's primary benefit is ensuring that potentially harmful, incompatible uses of neighboring properties will not threaten their properties and their legitimate uses.

But zoning codes, frequently drafted by lawyers rather than designers, tend to be too free and flexible where more guidance is needed and too limiting where flexibility is appropriate. Typically, the most constraining inflexibility concerns zone boundaries and use limitations, especially prohibitions against mixed-use development. The most problematic over-flexibility is the lack of clear criteria to guide site planning, streetscape design, building massing and architectural form.

Consequently, conventional zoning has produced patchwork quilts of single-use districts and private enclaves, often with minimal vehicular, pedestrian or visual connections between neighboring zones. It guarantees automobile dependency and, within neighborhoods, reinforces socioeconomic homogeneity and isolation from other neighborhoods.