SPATIAL PRICE POLICY AND THE DEMAND FOR TRANSPORTATION

For a spatial market of given radius transportation cost per unit sold is less under mill pricing than under any uniform pricing. This is true whether profit-maximizing monopoly prices or welfare-maximizing prices or any other prices are chosen.     

SHIPPING COSTS,INFORMATION COSTS,AND THE SOURCES OF INDUSTRIAL COAGGLOMERATION*

ABSTRACT Direct trade between establishments, coupled with costs of trading goods and information across space, has long been considered a primary determinant of industrial colocation. However, researchers have had difficulty decomposing the effects of interindustry trade into these two cost components. Using new techniques for separately estimating shipping and information costs, this paper provides an empirical framework for identifying the various sources of industrial coagglomeration among U.S. manufacturing industries. My findings suggest that both interindustry shipping costs and information costs influence metropolitan‐level coagglomeration. Additional evidence points to the significant role of direct information costs in determining intraindustry agglomerations.     

中国城市航空运输职能等级及航空联系特征的实证研究

本文依据城市航空运输资料,分析了中国城市航空运输职能等级层次,并揭示了城市航空运输联系所反映出的中国城市体系的宏观特征。     

A GENERAL FRAMEWORK FOR THE INTEGRATION OF A LAND-USE MODEL WITH A TRANSPORTATION MODEL COMPONENT

Integrated land-use—transportation models are characterized as models in which the redistributive effects of one subsystem upon the other are explicitly defined and incorporated into the model's structure. At the core of integrated models is a linking procedure whose function is to transform the outputs of one model component into inputs for the other. Despite major efforts made in the past to build operational large scale integrated models, the structural properties of such models remain largely unexplored. This paper describes a general framework for an integrated model consisting of prototype model components. These are an iterative activity allocation model of the Garin-Lowry type, an equilibrium-assignment transportation network model, and a linking procedure. Given the level of analysis, this framework is shown useful for exploring the analytics of integrated models and, in particular, their equilibrium properties. By means of many simulation experiments based on an hypothetical numerical example, the operation of the model is demonstrated with an emphasis on the locational interpretation of the integration procedure. On the basis of the empirical results and considering the model's intrinsic assumptions, the following major findings can be cited. First, the effects of nontravel factors (such as basic employment and zonal attractions) upon activity distribution are stronger than effects caused by changes in the transportation system. The latter effects were found to yield nonlinear and, spatially, nonuniform changes in activity location which also tended to be larger in peripheral regions. Second, implicit in the specification of the integration procedure are behavioral assumptions regarding time-lags in locational adjustments made by activities in reaction to rising cost of travel. The present formulation implies that once located, activities do not revise their locational decisions despite substantial increases in travel costs. At the other extreme, all activities are permitted to readjust their locational preferences after the final interzonal travel costs are derived. The effect upon activity distribution of the latter specification is, of course, larger than that of the former, although less than the effect yielded by changes in nontravel factors. Regarding the equilibrium properties of the integrated system, both the theoretical and empirical analyses show that the entire model will converge into an equilibrium solution and that the corresponding trip patterns are also at equilibrium. These results will hold as long as the operation of the integrated models is completely controlled by the generation functions of the land-use model and the transportation model component only affects the spatial distribution of activities. Finally, the results from the simulation experiments indicate that the computed mean travel cost parameter tends to stabilize around a certain value as the level of demand for travel, within the system, rises. There is evidence that compensating changes in the location and composition of this demand are the main causes of this phenomenon. In light of these findings, it is possible to point to three key problems whose resolution could largely improve the predictive power of integrated models. First, it would be useful to define activity models in which the generation of activities is, among other things, a function of travel conditions. Second, currently formulated integrated models do not contain trip demand functions and, thus, demand for travel by an activity unit is regarded as completely inelastic. Third, different locating activities respond differently—over time and space—to changíng travel conditions, and models should, therefore, reflect explicitly such differences in activity behavior. A recent paper by Los [14], is an important contribution to the analysis of this issue.     

CONSTRUCTION COSTS AND THE SUPPLY OF HOUSING STRUCTURE*

ABSTRACT Construction costs account for the bulk of the price of new houses in most markets, but their study has been relatively neglected. We document that there are economically large differences in construction costs across U.S. housing markets. We also estimate a very elastic supply for physical structure; hence, differences in construction activity across markets do not explain the variation in costs. Supply shifters that collectively do account for differences in building costs include the extent of unionization within the construction sector, local wages, local topography in terms of the presence of high hills and mountains, and the local regulatory environment.     

THE SIZE OF NATURE RESERVES AND COSTS OF THEIR MAINTENANCE

A paper devoted to nature reserve size in the USSR, and more specifically to whether the areas of such reserves are adequate in particular natural zones and for particular species, determines that too many zapovedniki presently are too small to carry out their intended functions properly. In fact, until quite recently, in spite of a dramatic expansion of the total area and number of nature reserves, average reserve size has decreased. A trend toward decreasing reserve size and increasing per hectare maintenance expenditures can be noted as the level of economic development characteristic of particular natural zones increases (translated by Jay K. Mitchell, PlanEcon, Inc., Washington, DC 20005).     

TRANSPORTATION RATES AND LOCATION OF THE FIRM: A COMPARATIVE STATIC ANALYSIS*

ABSTRACT This paper examines the role of the structure of transportation rates in the Weber-Moses triangle model. It shows that, in Zeigler's analysis, the appearance of the price elasticities of demand for inputs actually vanish by a simple application of the envelope theorem. Applying comparative statics analysis, we show when transportation rates are a function of quantity and distance, the assumptions that the production function is homogeneous of degree one and the transportation rates elasticities with respect to quantity and distance are constant are not sufficient to insure that the optimum location is independent of the level of output. This result is significantly different from that obtained by either Miller and Jensen or Zeigler.