John Odland

THE CONDITIONS FOR MULTI-CENTER CITIES

A set of formal conditions for multi-center versus single-center urban forms are derived in this paper, from a mathematical programming model of the spatial arrangement of a city. These conditions indicate that singlecenter arrangements prevail when the marginal costs associated with production, transportation, and residential crowding are small compared to the population and area of the city. The formal conditions are compatible with a class of urban population density functions and this makes it possible to devise a statistical test of the hypothesis of monocentricity. Empirical results for four midwestern cities in 1960 and 1970 indicate that the singlecenter assumption may be untenable. The assumption of a monocentric city structure can greatly simplify the construction of formal models of urban land use patterns, but models which depend on the monocentricity assumption may fail to describe some important features of land use patterns and may conceal important theoretical considerations. The assumption that relevant interactions, especially worktrips, are directed toward a single center generally leads land rent functions, and associated distributions, to assume forms which are continuous, monotonic, and radially symmetric. The simplicity of these forms makes it possible to derive qualitative implications about issues such as the equilibrium distribution of population [1; 4] or the effect of traffic congestion on equilibrium land use patterns [11]. Many of these results would be difficult or impossible to obtain without the single-center assumption. The monocentricity assumption may, however, be untenable in the face of contemporary processes of decentralization which apparently favor the development of dlispersed or multicenter patterns of employment and interaction [101]. The disagreement between the monocentric assumption and observed city forms is especially important in cases where implications drawn from single-center models become invalid or seriously distorted when applied to multi-center cities. The research presented in this paper is an attempt to identify the theoretical and empirical limits of the monocentricity assumption. A general model of the spatial arrangement of urban land uses is presented in which monocentric city forms are a subset of the possible range of solutions. Monocentric solutions are shown to prevail when land use patterns are determined under particular sets of conditions which include conditions on city size, transportation cost, production conditions, and conditions for the consumption of housing. The conditions under which monocentric urban forms can be expected are derived and discussed in an abstract way. It is shown that, in general, monocentric forms prevail when the marginal costs associated with production, transportation, and residential crowding are small compared to the population and area of the city. The class of single-center solutions is also compatible with a class of simple urban population density functions and

Migration, Functional Distance, and the Urban Hierarchy

origin and destination [13, pp. 49-50]. In general, the net effect of these properties may be viewed in terms of the functional distance between any two places (or nodes). If each nodes (n) properties are mapped in an n-dimensional space, it is possible to compute a measure of distance separating any two nodes, termed functional distance, such that it reflects the net effect of nodal properties upon their propensity to interact [6]. In this context it is understood that lesser func-

Interdependencies in the timing of migration and mobility events

Methods for examining interdependencies between the timing of migration events and other major events in the life histories of individuals are presented. Individual locational histories are treated as realizations of discrete-state, continuous-time random variables, with migration or mobility events corresponding to transitions between states. The timing of migration is compared to the timing of other transitions in individual life histories, including changes in household organization and labor force status, by investigating the durations of time separating the two kinds of transitions. Empirical investigations are carried out using longitudinal data from the Survey of Income and Program Participation.

Household organization and the interregional variation of out-migration rates

Regional out-migration rates may depend on localized conditions, but the range of possibilities for migration decision making in multi person households includes processes in which the response to variations in localized conditions depends on household size. Analyses of migration rates for households indicate that larger households exhibit more extreme responses to variations in localized conditions and that this is an important source of variation in regional out-migration rates.

Localized externalities, contagious processes and the deterioration of urban housing: An empirical analysis

Abstract Housing deterioration can develop in spatial-temporal patterns which are compatible with the operation of localized externalities if deteriorated structures exert negative effects on the condition of nearby structures or if structures are affected by unfavorable conditions which are endemic to entire neighborhoods. The pattern of housing deterioration in space and time is examined, using a time series of housing condemnations for Indianapolis. A non-linear logit model with a spatial-temporal lag structure is used to analyze the association between the occurence of new condemnations and the location of existing condemned structures. The model predicts the probability that a housing condemnation occurs within a given time period as a function of the numbers of condemned structures in the same area and adjoining areas at the beginning of the time period. The size of the areas is flexible and an appropriate scale for the process is identified by varying the size of the areas.

Changes in the Inequality of Earnings for Young Men in Metropolitan Labor Markets, 1979–1989: The Effects of Declining Wages and Sectoral Shifts within an Efficiency Wage Framework

Abstract Inequality in the earnings of young men with different educational backgrounds has grown rapidly in the United States in recent years, but the growth of inequality has varied widely across different metropolitan labor markets. We examine the increasing inequality of earnings among young men in the largest metropolitan areas of the United States for the 1979–1989 period and develop explanations for the growth of inequality that involve shifts of employment from highly paid to poorly paid sectors and declines in earnings within sectors. Our explanations depend on the logic of efficiency wage models. Efficiency wage models allow wages to include noncompetitive premiums that may differ across industries and regions because of differences in production conditions. This makes it possible for the real wages of identically qualified workers to differ across industries and regions, even at equilibrium. Shifts in the employment of less-educated young men from well-paid to poorly paid sectors (such as manufacturing to services) accounted for only minor portions of the growth of inequality. Most of the growth of inequality resulted from declining earnings within sectors, especially in those sectors and metropolitan areas where earnings for less-educated young men were highest in 1979, relative to the earnings of young men with more education. This pattern of earnings declining most rapidly in sectors and cities where they had been highest also accounts for much of the variation in the growth of inequality across metropolitan areas and is consistent with the demise of efficiency wage premiums that were previously available in particular industries and localities.

Urban travel alternatives: Models for individual and collective preferences

Abstract A method of estimating preference functions for alternative urban travel modes using non-metric scaling and conjoint measurement is introduced. The method treats travel alternatives as alternative collections of generic attributes and disaggregates preference orderings for alternative modes into components associated with the generic attributes. Preference functions are fitted for individual respondents and alternative methods of estimating collective preference functions for the group of respondents are examined. Particular attention is given to the error associated with aggregating individual responses. The methods are designed to be effective with relatively modest quantities of survey data.

Intermetropolitan Variation in the Labour Force Participation Rates of White and Black Men in the United States

We decompose the variance in black and white male labour force participation rates across US metropolitan areas in 1990 into three effects: that due to variation in labour force participation within labour force categories across metropolitan areas (local labour market effects); that due to variation in the distribution of those categories across metropolitan areas (labour force structure effects); and that due to the covariation between these two effects. Variation in labour force participation rates within labour force categories (local labour market effects) accounts for 56 per cent of the variance in labour force participation rates across metropolitan areas for white men but over 75 per cent for black men. Variation in the frequency of membership in each labour force category is a relatively unimportant factor for both groups. The covariance between labour force effects and local effects is negligible for black men but accounts for 25 per cent of the intermetropolitan variance in white male participation rates. This covariance is a measure of how well adjusted the labour force characteristics of metropolitan areas are to local economic conditions; our results indicate that this adjustment is greater for white men than black men. We also use this decomposition to identify the causes of variation in the difference between black and white labour force participation rates. Black-white differences in response to local labour market effects conditions generate most of this variance. These different local labour market effects are greatest among young single men with less than a high school education.