Agenda - Planning Commission - 03/06/2008

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erty tax assessor's, to identify the existing land use of each parcel. Once the database is set up, annual (or even continuous) data updates can provide policy makers with accurate information about absorption of land. Land market monitoring explains not only existing land-use patterns, but also allows projections of land availability into the future. If zoning and infrastructure infor- mation is available, vacant land can be ana- lyzed to determine the number of residential units that can be accommodated. This becomes the effective supply of housing over time. To estimate demand, popuiation projections from state or national data sources can be adapted to local conditions. A comparison of projected supply and demand for housing can identify gaps or sur- pluses of supply. Where demand outpaces supply, annexation, expansion of growth boundaries, or another growth management tool is needed. Where supply isable to meet or exceed demand, requests to open new land for development can be postponed until demand catches up. Land market monitoring can also be tailored to local needs. For examp1e, estab- lished communities may not have a large supply ofvacant land. Although the land market monitoring process may uncover some pockets of land that can be redevel- oped (for example, lots that back up to one another), planners can explore other alterna- tives. They can estimate a property's rede- velopment potential based on the ratio of a structure's value to the value of the land it is built on. Other innovations may also be needed to address large-scale land-use changes, such as closing a military base or building a new airport. With a land market monitoring system in place, communiti~s can evaluate trends in housing location and type. For example, some communities may see growth in demand for multifamily units as housing prices increase. This would point planners toward a review of vacant land to see if an oversupply of single-family zoning is limiting the locations for multifamily devetopment. LAND MARKET MONITORING CAN SUPPORT POLICY DECISIONS A detailed and timely land market monitor- ing system ensures that policy tools to regu- late the supply of land are effective. One effective tool is to adopt an urban growth boundary (UGB), which allows higher densi- ties inside the boundaries and limitsdevel- opment outside. The best UGBs are large enough to allow for adequate housing choices and stable land prices, but small enough to ensure that development is com- pact and efficiently located. Some communi- ties, pressured by political needs or power- fullandowners, may adopt a UGB that is so large that it can be ignored for the next 10 to 20 years as land is absorbed into the hous- ing market. Another pitfall is not expanding a UGB enough: The state of Maryland, for . example, restricts most growth-related state infrastructure investments to so-called prior- ity funding areas, yet local governments are. not required to expand such areas as devel- opment capacity is absorbed. In locations without UGBs, zoning decisions can have similar impacts: A downzoning can decrease the supply of available land as effectively as a UGB. Such inadequate attention to urban land and housing markets can lead to land and housing price inflation and can, by deflecting growth to even less preferred locations, exacerbate urban sprawl. Land market monitoring can help pre- dict when to add land to a UGB or when to upzone property. Past trends in land absorp- tion provide estimates for how much land should be added. Although there is no exact science to determining when and how much land to open for development, the data sup- plied by the land market monitQring system can provide ample support for a middle-of- the-road solution, calming developers who fear they will not Find available land, and calming residents who fear longer com- mutes and more traffic that may result from too much uncoordinated growth. CASE STUDIES The following jurisdictions show how land market monitoring can be useful at regional, countywide, and city-specific scales. While each takes a different approach to gathering data, over time they have all been able to shape land-use decisions in ways that maxi- mize the use of infrastructure and minimize impacts to the environment. Portland Metro Area Land-use decisions in Portland, Oregon, are governed by Metro, the elected regional gov- ernment for the three-county Portland met- ropolitan area. Metro adopted an urban growth boundary in 1979. State law requires Metro to manage Portland's UGB by demon- strating that it includes a sufficient supply of land to provide for 20 years of future resi- ZONING PRACTICE 1.08 ~ AMERICAN PLANNING ASSOOATlON I plg~ 7