This year marks the bicentennial of Pierre L'Enfant's extraordinary plan for America's national capital, a design on paper that was implemented with reasonable fidelity and that today, 200 years later, still shapes the city of Washington.

Unfortunately, land planners haven't done as well since.

Citizen resistance in the 20th century to affirmative planning, urban design and land use regulation continues to amaze many American planners who have witnessed the sprawling and "malling" of the American landscape over the past half century with increasing alarm.

It's not that plans haven't been created, nor has there been a shortage of talented and dedicated design professionals ready to invent and advocate such plans. But plans, no matter how inspired, are meaningless unless they are officially adopted and carried out under the laws of states, counties and municipalities -- which, of course, introduces politics into the process.

And the greatest impediment to effective urban planning has been political opposition to philosophies and methods of interventionist land use regulation. That opposition is founded on the notion that private property rights are sacred, that land is a freely marketable commodity over which owners have absolute dominion, that government should not tell people how to use land.

Even zoning, the legal means for controlling land use in the United States since the 1920s, has served primarily to preserve or extend existing land use distribution patterns and density, along with protecting property values. Rarely do zoning regulations embody proactive planning or urban design concepts comparable to L'Enfant's plan, a plan concerned more with street and spatial patterns than with types and densities of land use.

Throughout America local jurisdictions have committed the same fundamental sins. They have prematurely zoned urban hinterlands; failed to use public infrastructure -- roads, water and sewer -- to guide private development; avoided establishing design standards other than engineering criteria; prescribed insufficient density where development was sanctioned; and inadequately safeguarded environmental resources.

The negative results of America's 20th century approach to land use planning -- let the market, almost alone, dictate -- are becoming increasingly noticeable, and painful, in cities and suburbs throughout the country: traffic congestion and protracted commuting time, overburdened public infrastructure, diminishing air and water quality, loss of agricultural land and destruction of natural landscapes and wildlife habitats, especially wetlands.

In many localities, residential land and housing costs, driven upward in part because of restrictive zoning, have made affordable housing feasible only at great distances from cities and employment centers. The result is that daily gridlock now occurs on remote, country roads.

L'Enfant's plan for Washington gave succeeding generations a memorable, relatively immutable network of great public avenues, civic spaces, orderly streetscapes, urban landmarks and monumental points of focus. This collective realm is defined and reinforced by an evolving fabric of individual, stylistically and functionally diverse buildings that nevertheless contribute to the whole cityscape. By contrast, the modern American legacy for subsequent generations will be a spatial realm of parking lots, 12-lane commuter highways and interiors of automobiles probably manufactured abroad.

But there is renewed hope. Increasing numbers of citizens, public officials and private developers are reconsidering conventional land use policies and practices. There are signs that during the last decade of the 20th century, new thinking may emerge, accompanied by new governmental initiatives, that could positively reshape future American urban and suburban growth.

Consider the following:

The city council of Houston, the only major U.S. city without zoning laws, a city of laissez-faire growth and leap-frog development, has created a planning and zoning commission. If that organization it can act boldly, it may not be too late to remedy some of Houston's deficiencies.

A number of states, Maryland being among the most recent, are enacting legislation mandating statewide comprehensive land use planning. Local jurisdictions not only must prepare plans and regulations that meet statewide criteria, they also must coordinate their planning with neighboring cities and counties to ensure compatibility in the interest of regional planning goals.

Many counties and municipalities throughout the country have revisited their existing planning and zoning laws and have begun creating new land use regulations. Among the most common and controversial proposals is the delineation of urban growth boundaries, well-defined edges of development districts in which future growth will be concentrated. Land outside such boundaries would remain rural or would be preserved in its natural state.

Local jurisdictions are also beginning to require more of developers. Governments are imposing impact fees or demanding proffers intended to cover costs of public services and infrastructure necessitated by project development. More stringent design standards -- pertaining to site planning and landscaping, for example -- coupled with project design review are being used to upgrade the aesthetic quality of what is built.

Public officials are realizing that transportation planning and improvements may be the most powerful tool for channeling growth, even more so than zoning.

Perhaps only the current recession and slowdown in real estate development are providing the pause needed to deliberate new land use policies. If so, an upturn in the economy, with renewed growth pressures, may well rekindle the political resistance to these policies.

But perhaps not. Even some of the most ardent free-marketeers in business and government have come to understand that managed growth, proactive transportation and land use planning, and creative urban design ultimately make good, economic sense. Let the recession end, but let's continue to pursue new and wiser approaches to land use.

Roger K. Lewis is a practicing architect and a professor of architecture at the University of Maryland.