By Roger K. Lewis
Saturday, March 4, 2006
Urban design thinking and practice have greatly advanced over the past 30 years. Unfortunately, conventional zoning, the crude but all-powerful regulatory tool shaping cities, has changed little. Given the need to transform land-use planning and development, why is it so difficult to transform conventional zoning?
Impediments to zoning reform are predominantly political, social and economic, usually having little to do with design.
Holistically amending a jurisdiction's zoning statutes and regulations requires both executive leadership and legislative action. Because strong political sentiment always arises in opposition to proposed changes in land development, most elected officials and their constituents are reluctant to contemplate and push for such changes.
Zoning is potent because once zones are mapped and categories of land use, land-use intensity and building criteria are prescribed, the future character of the physical environment, along with its potential economic value, is substantially determined.
Land zoned for only single-family detached houses, with lots no smaller than 10,000 square feet, is likely to be less valuable than land zoned for attached homes or apartment buildings. If that same land is zoned for commercial use, its value becomes even greater.
Zoning creates vested land-use rights and potential wealth for property owners. In fixing boundaries, uses, densities and building form, zoning also presumably creates stability and predictability. Thus many oppose zoning changes because they see it as a threat to their neighborhood and property.
In many areas, zoning effectively excludes less affluent people from property ownership by generating land scarcity and unaffordable land costs through constraints on use.
Although many have benefited economically from zoning, it has become increasingly ineffective as an instrument of urban design. Zoning's fundamental flaw is that it operates primarily by setting limits, spelling out what cannot be done, while remaining relatively mute as to what should be done.
Zoning laws often were written by lawyers, not by planners and designers. Regulations adopted decades ago under radically different circumstances are still on the books. Among the most obstructive regulations are these limiting types of use and mixing of uses. People once believed that proper planning required clearly separated, single-use zones. A further belief was that, within a zone, buildings should be similar in bulk, height and character.
Today, urban designers advocate mixing uses and building types, blurring lines of demarcation between urban and suburban neighborhoods. They strive for connectivity rather than separation, heterogeneity rather than homogeneity.
Density is another concern. Over time, new technologies, new architectural design strategies, new transportation modes and new patterns of human behavior make previous assumptions about density obsolete. Allowable densities stipulated 40 or 50 years ago for a city may make little sense today in the face of dramatic changes in demographics, infrastructure, building types and land development costs.
But by far, zoning's most significant deficiency is its failure to mobilize regulatory power in determining the quality of the public realm -- the design of streets, civic spaces and public parks.
Typically, jurisdictions address the public realm, if at all, in broad-brush master plans, but often vaguely and without the kind of exacting constraints imposed by zoning. Rarely do zoning ordinances and master plans set forth adequate design standards for street cross sections, planting, furniture, lighting, sidewalk dimensions and finishes, building porosity at sidewalk level, or graphics. Rarely are plaza geometries or landscaping spelled out.
Instead, most jurisdictions fabricate a patchwork quilt of uncoordinated ordinances that deal separately with transportation, public works, utilities, building and public safety codes, and parks and recreation.
Ideally, a new set of principles and rules for urban design and development, superseding zoning, would explicitly and comprehensively address all of these issues: patterns of land use, densities, infrastructure, building form and, equally important, cityscape and landscape. And to be effective, its mapping and design criteria would be fine-grained, ranging in scale from districts and neighborhoods to specific sites.
A new code still would need to prescribe limits where appropriate, but its aim would be higher: to achieve desired aesthetic quality and functionality within the public realm.
Of course, debates about desired aesthetic quality won't go away. Urban designers share many goals, but competing aesthetic philosophies persist, just as in other design fields, such as architecture, furniture and fashion design.
Boiled down, the debate is between those embracing historical continuity and those advocating innovation. The former generally want to be more prescriptive about both cityscape and architecture, while the latter, fearful that freedom of artistic expression could be stifled, seek to promote design flexibility.
But each community must engage in this debate, a necessary part of the process required to transcend conventional zoning.
No matter which aesthetic philosophy a community chooses, residents must remember that cities are at once permanent and organic, durable yet mutable. While laws regulating urban development should not be changed solely in response to rapidly shifting trends in taste, they nevertheless must change from time to time. For zoning, this is one of those times.
Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.