Optimal policies in cities with congestion and agglomeration externalities: Congestion tolls,labor subsidies,and place-based strategies

This paper develops a spatial general equilibrium model that accommodates both congestion and agglomeration externalities, while firms’ and households’ land-use decisions are endogenous across continuous space. Focusing on the interaction between externalities and land use patterns, we examine the efficiencies of first-best policies and second-best pricing and place-based strategies using numerical simulations. A first-best policy must combine both Pigouvian congestion tolling (PCT) and Pigouvian labor subsidies (PLS) instruments, or design an optimal toll (or subsidy) internalizing agglomeration externalities (or congestion externalities). We also examine second-best pricing policies if only one instrument is adopted. Congestion pricing policies alone (e.g., a partial PCT or a flat-rate toll) can improve social welfare only in heavy-congestion cities, and their welfare gains may be insignificant (e.g., below 10% of the welfare improvement achieved by first-best policies). In contrast, second-best labor subsidy policies alone are a more effective alternative to first-best policies. As to place-based policies, the firm cluster zoning (FCZ) regulation is more efficient than the urban growth boundary (UGB) policy. UGBs only have small effects on the agglomeration economy but could worsen land market distortions via residential rent-escalation effects. These findings suggest that it is important to internalize business land use decisions and relax monocentricity assumptions, in order to appreciate the interplay of both urban externalities, since spatial adaptations to policy interventions can distort system efficiencies.     

The Nature of Urban Land

A bstract . Considerations about land interpose into almost every aspect of urban life. They may not be the only factor determining a city's well-being but appropriate land policies are necessary to bring about prosperity and equity. Contemporary accounts of the 'urban crisis' and of urban problems reveal the pervasiveness of land issues. Use of one urban land parcel has bearing on the usability of neighboring sites, which makes land a community resource. Urban land may be defined as land used or expected to be used for urban activities. Its attributes include location, space, property, clustering, heterogeneity and immobility and indestructibility. Neo-classical theorists, by stressing accessibility and ignoring externalities and other attributes of land, achieved only an unrealistic understanding of it. Most land economists are institutionalists , their theory encompassing long-validated concepts about the nature of land. The neo-Marxian approach has many points of congruence with the institutionalist one. Empirically investigated, urban land is found to be different from economic goods and hence its production, allocation and disposition must proceed at least like other public goods.     

Congestion,agglomeration, and the structure of cities

Congestion costs in urban areas are significant and clearly represent a negative externality. Nonetheless, economists also recognize the production advantages of urban density in the form of positive agglomeration externalities. The long-run equilibrium outcomes in economies with multiple correlated but offsetting externalities have yet to be fully explored in the literature. Therefore, I develop a spatial equilibrium model of urban structure that includes both congestion costs and agglomeration externalities. I then estimate the structural parameters of the model using a computational algorithm to match the spatial distribution of employment, population, land use, land rents, and commute times in the data. Policy simulations based on the estimates suggest that congestion pricing may have ambiguous consequences for economic welfare.     

论城市规划和管理中的规制和利导原则及其应用

论文认为由于城市中存在大量的负经济外部性,应建立与市场有机结合的一套规则或制度引导城市健康地成长和发展.像市场规制在其他领域一样,城市管理和规划中的市场规制原则为:使私人成本等于社会成本,私人收益等于社会收益.在社会主义市场经济条件下,城市规划者可以通过对自己掌控的、影响城市发展和空间配置的要素的规划来引导城市达到其合理结构.因势利导的原则除了系统性外,还有近远期相结合的原则.论文对规制和利导原则在交通结构和交通定价、土地合理定价与土地利用、城市空间战略、土地利用和交通系统、城市发展与土地供给等方面的应用进行了论述.     

The Lowry Model Revisited: Incorporating a Multizonal Input-Output Model into an Urban Land Use Allocation Model

This paper formulates a new generation of Lowry-style models that combine a multizonal input-output model and an urban land use allocation model. Three different types of models are proposed: 1) an unconstrained model, 2) a primal of a linear programming approach that includes land supply constraints, and 3) a modified dual of the linear programming approach that allocates land based on additional conditions of economic efficiency. The modified dual formulation improves upon the limitations of Lowry models and their derivatives. First, the proposed model has sound theoretical underpinnings that incorporate the production theory of input-output models and the behavioral theory of optimization models. Second, the proposed model allocates land on the basis of economic efficiency by imposing a procedure that equalizes shadow prices. And third, the proposed model is an optimization model that fully accounts for the spatial and sectoral relationships of multiplier effects determining land use demand.     

Thick market externalities in a spatial model

It is natural to think of thick market externalities as spatial phenomena. When agents are in close physical proximity, potential trading partners are more numerous and less costly to reach. Counteracting such agglomeration benefits is the dispersion force due to land being an essential input in production. The distribution of economic activities over space is an outcome of how decisions on location, land demand, and the search strategy of agents interact in spatial equilibrium. More desirable locations are those that allow their occupants more abundant and less costly access to potential trading partners. In spatial equilibrium, these are the densest locations, the occupants of which benefit from the strongest thick market externalities.     

北京市写字楼市场空间一体化模型研究——基于UrbanSim的模型标定与情景模拟

城市空间仿真系统(UrbanSim)为构建城市土地利用和交通空间一体化模型提供了基础平台。以写字楼市场为研究对象,基于企业选址和写字楼开发选址的相关理论构建了写字楼市场供给(开发选址)与需求(企业选址)一体化模型,通过地理信息系统(GIS)建立了北京市写字楼开发/价格、企业选址及城市基础设施和公共服务的空间数据库,并在UrbanSim平台上利用这些空间微观数据对写字楼市场一体化模型进行了标定。利用已标定的一体化模型,论文进行了城市政策效果和城市发展的情景模拟,包括轨道交通建设对企业选址和开发选址的影响,以及北京市两个重要的商务办公区(商务中心区和金融街)功能区扩张的预期效果。     

城镇化发展中城市土地供应有关问题的探讨与分析

城镇土地供应机制经过不断的探索和实践,以土地使用权出让为主要方式的城市土地供应机制已经建立。城镇化的发展使得土地资源的供应与社会需求之间矛盾呈失衡的发展态势。探讨和分析城市土地供应问题,合理引导控制城镇化进程中城市土地供应,优化城市土地利用结构和实现土地资源更好的配置具有重要意义。     

Land use dynamics and the environment

This paper builds a benchmark framework to study optimal land use, encompassing land use activities and environmental degradation. We focus on the spatial externalities of land use as drivers of spatial patterns: land is immobile by nature, but local actions affect the whole space since pollution flows across locations resulting in both local and global damages. We prove that the decision maker problem has a solution, and characterize the corresponding social optimum trajectories by means of the Pontryagin conditions. We also show that the existence and uniqueness of time-invariant solutions are not in general guaranteed. Finally, a global dynamic algorithm is proposed in order to illustrate the spatial-dynamic richness of the model. We find that our simple set-up already reproduces a great variety of spatial patterns related to the interaction between land use activities and the environment. In particular, abatement technology turns out to play a central role as pollution stabilizer, allowing the economy to reach a time-invariant equilibrium that can be spatially heterogeneous.     

我国普通商品住房供求的影响因素及其稳定性研究

本文利用1997年到2009年全国以及各地区的房地产面板数据,借鉴蛛网模型的相关理论,构建供给与需求的联立方程,选择固定效应IV估计法拟合面板联立方程模型,对普通商品住房供求的影响因素及其稳定性进行了实证研究。结果表明,我国的普通商品住房市场处于不稳定状态,普通商品住房当期及滞后期的价格、城镇人均可支配收入、城镇就业人口、土地购置面积、经济适用房、别墅的供求状况等因素都对普通商品住房的供求变化产生较为显著的影响。     

Urban land use allocation and environmental pollution control: An intertemporal optimization approach

This paper deals with long-run, multiperiod strategies of environmental pollution control and allocation of urban land uses. Air pollution generated by the industrial, residential and transportation sectors is taken as representative of the urban environmental quality problem. A comprehensive urban development optimization model is presented, integrating three submodel components for industrial, residential and transportation activities. The analysis focuses on the intertemporal linkages between technological and locational decisions, accounting for land availability, air pollution generation, control and impact, technological change, relocation of activities, land development and redevelopment, and transportation flows and network expansion. The modeling approach is of the cost-effectiveness type: the efficiency criterion is the total intertemporal cost of urban development and operation, and the objectives of the environmental policy are expressed in terms of standards to be respected. The methodology is illustrated by an empirical application to the Haifa metropolitan area.     

土地资源配置的空间尺度差异分析

由于我国正处于区域经济一体化和城乡统筹的大背景下,土地利用规划呈现出与建设用地的快速扩展无法适应的态势。为了使土地高效、节约利用关键是协调区域经济发展与土地资源配置之间的关系,而依据现行的行政区划划分建立的土地资源配置体系存在很多弊端。因此,有必要对不同空间尺度下的土地资源配置的差异性进行分析,才能建立一个从宏观到微观的优化配置体系,实现土地可持续利用的目标。     

A computational approach to resource allocation in spatial urban models

This paper synthesizes and generalizes recent literature on the use of ‘fixed point methods’ to compute approximate numerical solutions to general equilibrium models of urban land use. We show how a broad array of spatial urban models, including ones involving endogenously generated externalities, can be studied within the context of a single unifying computational framework.     

The social cost of through traffic: Contribution to the suburban-central city exploitation thesis

This paper deals with the conflict between local and through traffic when allocating land for transportation at the expense of residential consumption. The model developed in this paper gives the optimal allocation of land between both uses, via Pontryagin's Maximum Principle, and shows the impact of through traffic on the urban structure, on local transportation costs and on the cost of housing supply. The cost functionals are used to measure the total burden to the inner city and a connection is made to the ongoing discussion of the ‘exploitation’ thesis.     

Neighborhood amenities: An economic analysis

A spatial model of household and firm demand and supply of market goods is developed. Housing and neighborhood amenity markets are explicitly considered in deriving market equilibrium. The equilibrium relationships are empirically investigated, yielding important insights into the functioning of the urban economy. Attention is focused on externalities involved in neighborhood markets and the simultaneous determination of housing and amenity market equilibrium. The effect of neighborhood amenities on household equilibrium is of a major magnitude and effects of “externality” variables on both housing and amenity equilibrium are substantiated. The degree of neighborhood homogeneity and the extent of government programs aimed at neighborhood development are found to have significant impacts on housing and amenity markets.     

The general equilibrium effects of congestion externalities

This is the second in a series of three articles on the topic of congestion externalities. We use an urban general-equilibrium model to compute two types of cities: the market-equilibrium city, in which congestion externalities occur, and the optimum city. The optimum city has a more dispersed distribution of employment, and a more concentrated distribution of residence. If the population of the city is fixed, the optimum pricing of transportation generates a per capita welfare gain of $3.78 per week. If the population of the city is endogenous, the internalization of congestion externalities causes the city to grow.     

中国工业化、城镇化进程中的土地配置特征

基于已有的研究成果,通过系统的理论归纳与统计分析,提出了当前中国工业化、城镇化进程中土地资源配置的主要特征:第一,从部门配置角度看,表现为农业用地大规模非农化;第二,从产业配置的角度看,城乡用地结构快速转变;第三,从空间配置的角度看,土地利用的区域不均衡;第四,从功能配置的角度看,重经济效益轻生态效益。     

土地财政与最优城市规模

土地是有限的,完全依靠土地收入的发展模式是不可持续的。本文主要考察土地财政作为地方政府的一种融资渠道,城市建设用地规模的使用是否与城市人口规模的增加相协调,是否存在过度扩张城市面积促进地区经济发展的现象。为了分析土地出让收入(地租)、公共品供给以及城市规模之间的关系,本文以乔治亨利定理为基础,并引入林达尔均衡条件建立起最优城市人口密度理论模型。采用1999～2009年31个省面板数据对中国城市成本收益模型进行计量分析,结果表明全国26个省低于估算的最优城市人口密度,验证了中国存在城市面积的扩张与人口的增加不协调发展的情况。     

Land use externalities, open space preservation, and urban sprawl

Parcel data on residential land conversion are used to investigate how land use externalities influence the rate of development and modify policies designed to manage urban growth and preserve open space. Several “smart growth” policies are found to significantly influence land conversion, including a development clustering policy that concentrates development and generates preserved open space. In addition to directly affecting a parcel's hazard rate of conversion, this policy is found to affect neighboring parcels' conversion by generating a positive open space externality that hastens their development. The implication that the clustering policy could generate a more sprawled pattern of development is explored using spatial simulation.     

Identification in a model of sorting with social externalities and the causes of urban segregation

This paper discusses nonparametric identification in a model of sorting in which location choices depend on the location choices of other agents as well as prices and exogenous location characteristics. In this model, demand slopes and hence preferences are not identifiable without further restrictions because of the absence of independent variation of endogenous composition and exogenous location characteristics. Several solutions of this problem are presented and applied to data on neighborhoods in US cities. These solutions use exclusion restrictions, based on either subgroup demand shifters, the spatial structure of externalities, or the dynamics of prices and composition in response to an amenity shock. The empirical results consistently suggest the presence of strong social externalities, that is a dependence of location choices on neighborhood composition.