One of the most effective tools ever developed for curbing sprawl is the Urban Growth Boundary. The UGB, widely used in Europe, establishes a clear difference between the city and the countryside by drawing an actual "container" line around urban and town areas. States and localities then support residential and commercial development inside the boundary; beyond it, farmland, forest, and natural areas remain for the most part unchanged.

In 1973 Oregon became the first state in the nation to adopt this idea, and required every one of its cities and towns to draw a UGB. In 1990 Washington required local governments to establish UGBs around the largest and the fastest growing communities.

The reason more places haven't tried the approach is that boundaries are difficult to enact. Development interests and owners of large blocks of land typically attack them as a violation of private property rights, and wrongly accuse them of being an unecessary meddling by government into private decisions about how land is used. State lawmakers, in debt to these interests for their campaign contributions, generally crumble under the lobbying pressure.

Oregon and Washington prevailed because of the severity of their sprawling growth, the apprehension among residents that their states were in danger of becoming like California, and the ardent support and leadership of their governors.

One of the breakthroughs in Maryland's Smart Growth program is that it requires local governments to define "Priority Funding Areas" where state development dollars will be spent, but it does not draw a fixed line around them. And in the early years of the program the zones will remain fairly flexible. In general, any area in the state that has water and sewer lines and a minimum of two homes per acre qualifies as a Priority Funding Area eligible for state subsidies and investments.

By establishing a relatively generous definition of a Priority Funding Area and avoiding a cumbersome government process to refine growth boundaries on a map, Maryland was able to focus discussion on the central issue: How to make the best use of public dollars to guide development to appropriate areas.

Maryland's program is not intended to be as restrictive as Oregon's pioneering growth management law. But state officials believe Priority Funding Areas are a first crucial step to get citizens and local governments thinking and working in new, more sensible ways. And they are confident that the potential to strengthen the program will grow as the benefits to communities become more apparent.