Self-Learning Revival Policies in Urban Dynamics by Nathaniel Mass
The policy response can vary with the dynamically changing parameters of the system. "We will introduce a 'self-learning' revival policy," which is like a compensator in an electrical circuit. In urban dynamics, the rates of slum demolition and the incentives for new enterprises are adjusted each year according to the new parameters of the system.
"This policy is a fairly simple example of an engineering 'integral controller.'...The concepts of system sensitivity developed in this paper apply to a very broad class of systems. Frequently, changing parameter values in a social system can 'shift the mode of operation so as to affect the design of new policies.' A careful search for such influential parameters should accompany any policy design effort. Once an influential parameter has been identified, the analyst should look for ways to make the system insensitive to that parameter."
Control of Urban Growth by Jay W. Forrester
Forrester suggests some policy tools to implement solutions from urban dynamics models.
Money - "The trend toward interpreting urban problems as a financial demand on higher levels of government must be reversed. Higher levels of government can be most effective by exerting pressures for local action, by altering the tax policies that encourage the perpetuation of old buildings in declining urban areas, and by reversing the policies that favor housing over jobs so that residential construction will no longer rise beyond the economic population-supporting capacity of the area."
Tax Laws - "The aging of buildings is an intimate part of the urban decline process. the shifting of taxes from real estate to incomes means that the old buildings and the land they occupy need not be used effectively; then can be allowed to decay with little tax penalty."
Population Density - "Population densities in both residential and commercial zones are allowed to rise in response to the fallacious argument that rising land prices require more intense use...we allow a land-price-population-density spiral to continue until excessive loads are thrown onto transportation, pollution, psychological trauma, and other factors of the urban environment."
Zoning - "Zoning as in the past divided land into blocks that are too large and too homogeneous that deteriorates as a whole into a substandard condition avoided by new construction to become a slum. Too much area is also zoned for residential use compared to industry. The failure to zone so that only forest and agriculture are allowed in rural areas immediately adjacent to urban areas permits urban sprawl to develop and removes the necessity to rebuild and reuse the aging urban areas."
Selected Stresses - "We must cherish and preserve the pressures that go with the chosen style of urban environment."
Realistic Goals - "We must contemplate realistic urban goals that include negative forces powerful enough to limit population and population density."
Control of Urban Growth by Jay W. Forrester
"This was presented as the keynote address to the meeting of the American Public Works Association in Minneapolis, Minnesota, Sept 25, 1972." Forrester makes a case for why technology in the form of more road infrastructure, sewage, and electrical wiring cannot solve the problems in a city without limiting the population density. Also, exponential growth cannot continue forever.
"Growth has continued past the point where suboptimizing is satisfactory. Suboptimizing means the meeting of a local goal without attention to consequences in other parts of the system. During the past period of our industrial growth, the various facets of the technical-social-economic system were sufficiently uncoupled that suboptimizing was a satisfactory procedure for decentralization. Suboptimizing allowed different groups to pursue their own ends independently, with confidence that the total good would thereby improve.
"I see no solution for urban problems until cities begin to exhibit the courage to plan in terms of a maximum population, a maximum number of housing units, a maximum permissible building height, and a maximum number of jobs.
"A city affects its local choice between quantity and quality mostly by how it handles the diffuse versus the compartmentalized components of attractiveness. The objective should be to maximize the diffuse characteristics of the city in order to improve the quality of urban life while controlling the compartmentalized characteristics in order to prevent the expanded population that would defeat the improvement for present residents. The diffuse characteristics, such as public safety and clean air, are shared equally by all...and they apply alike to present residents and those who might move in. The compartmentalized characteristics of a city, like jobs and housing are identified with particular individuals; they can be possessed by present residents but are not necessarily available to others."
Lowell Dynamics: Preliminary Applications of the Theory of Urban Dynamics by Walter W. Schroeder
The Urban dynamics modelers worked with the city of Lowell to discuss the biggest problems and make policy recommendations. There were nine "biggest" problems: unemployment, parking, transportation, taxes, city revenues, education, housing, crime protection, code enforcement, and federal and state controls.
They consider the two leading suggestions by the Lowell planners, which are to demolish the Mill and to impose a service tax plan on currently untaxed property. The analysis showed that demolishing the mill would be expensive, and one alternative would be to convert existing "large plant facilities to several smaller industrial condominiums...small-scale development would make it financially possible for small, young firms to locate in these structures. Since the condominiums would be organized such that none of the units could be demolished without the consent of the other occupants, the threat of forced relocation in the near future would be significantly reduced." The system dynamics analysis discourages the service tax plan. The problem is that more and more money will always be perceived as necessary.
Some really interesting results and policy recommendations had to do with land assessments, taxes, and zoning. One problem is that residential buildings are assessed at a lower value than commercial and industrial buildings so that businesses pay more taxes than the homeowner. This drives the trend towards excess housing.
Similarly, homeowners end up paying higher taxes than renters because of tax rules, and thus the area is trending towards higher-density living. The buildings then deteriorate faster because there is less incentive for the renter or landlord to maintain the facilities.
The authors recommend reducing the stock of substandard housing because "aged housing contributes little to the city's tax base or to its socioeconomic vitality." It would be best if landlords demolished or renovated their old buildings voluntarily. This can be done by limiting tax abatements that the city grants to owners of old buildings. "Should the owner fail to demolish, at least the more rapid buildup of back taxes would warrant the city taking a lien on the property before it loses all of its market value."
They also recommend reducing reliance on federal assistance for subsidized housing. Zoning can also help to create a healthy balance between residential buildings and commercial buildings.