variable returns to agglomeration and the effect of road traffic congestion abstract this paper investigates the links between returns to urban density productivity and road traffic congestion a generalised translog production inverse input demand function is estimated to test for the existence of variable returns to agglomeration in manufacturing construction and service industries two separate measures of urban density in which proximity is represented by straight line distance or by generalised cost are constructed and included in the translog to identify the effect of road traffic congestion the results show that for some sectors of the economy diminishing returns to urban density can set in causing the magnitude of agglomeration elasticity to fall as effective densities increase the generalised cost based measure of agglomeration produces higher elasticities because it captures both time and distance dimensions of density a comparison of spatial variance in estimates indicates that road traffic congestion plays an important role in explaining diminishing returns for the most highly urbanised locations

networking off madison avenue known for the key role that networking plays in the operation of agencies where interviews suggest that informal networking among close neighbors is critical to many agencies success networking involves the exchange of ideas and while there is no market place for these ideas exchanges may be more deliberate rather than just marshall s 1890 mysteries of the air type of information spillovers this paper examines the effect on productivity of having more near advertising agency neighborhoods and hence better opportunities for meetings and exchange within manhattan we will show that there is extremely rapid spatial decay in the benefits of having more near neighbors even in the close quarters of southern manhattan a finding that is new to the empirical literature and indicates our understanding of scale externalities is still very limited the finding indicates that having a high density of commercial establishments is important in enhancing local productivity an issue in lucas and rossi hansberg 2002 where within business district spatial decay of spillovers plays a key role we will argue also that in manhattan advertising agencies trade off the higher rent costs of being in bigger clusters nearer centers of action against the lower rent costs of operating on the fringes away from high concentrations of other agencies introducing the idea of trade offs immediately suggests heterogeneity is involved we will show that higher quality agencies are the ones willing to pay more rent to locate in greater size clusters specifically because they benefit more from networking while all 1 the research in this paper was conducted while the authors were census bureau research associates at the boston research data center research results and conclusions expressed are those of the authors and do not necessarily indicate concurrence by the census bureau the paper has been screened to ensure that no confidential data are revealed we acknowledge helpful comments from andrew foster on aspects of the paper and from participants in seminars at brown university lse and the university of toronto

production externalities and urban configuration abstract we formally explore jacobs idea that uncompensated knowledge spillovers are crucial for agglomeration by modeling location dependent interfirm production externalities in a general equilibrium linear city framework good and factor allocation firms and households locational choice and wages and land rents are all endogenously determined the unique equilibrium urban configuration may be concentrated with monocentric firm locations dispersed with completely mixed firm household locations or a combination depending on the population of firms transportation cost and firm interaction parameters due to distance dependent production externalities firms will be clustered together in any equilibrium thus ruling out the possibility of any multicentric urban configuration journal of economic literature classification numbers d51 r12

land use and density in cities with congestion abstract it was well documented that monocentric spatial models with congestion require driving tolls to generate market efficiency because driving and location are equivalent tolling congestion is the same as regulating density this paper shows that internalizing the congestion externality always requires upward adjustments to market density which are greatest at the urban center this holds whether or not transportation capacity is optimally provided simulations suggest optimal cities should have central densities that are orders of magnitude greater than market cities

second best congestion pricing schemes in the monocentric city abstract this paper considers second best congestion pricing in the monocentric city with endogenous residential density and endogenous labour supply a spatial general equilibrium model is developed that allows consideration of the three way interactions between urban density traffic congestion and labour supply congestion pricing schemes are analysed that are second best by design and not because distortions exist elsewhere in the spatial economy like cordon charging and flat kilometre charges both for cobb douglas utility and for ces utility the analyses suggest that the relative welfare losses from second best pricing compared to first best pricing are surprisingly small

gibrat s law for all cities two empirical regularities concerning the size distribution of cities have repeatedly been established zipf s law holds the upper tail is pareto and city growth is proportionate census 2000 data are used covering the entire size distribution not just the upper tail the nontruncated distribution is shown to be lognormal rather than pareto this provides a simple justification for the coexistence of proportionate growth and the resulting lognormal distribution an equilibrium theory of local externalities that can explain the empirical size distribution of cities is proposed the driving force is a random productivity process of local economies and the perfect mobility of workers

commuting congestion and employment dispersal in cities with mixed land use abstract for centuries cities have been modeled as having centered employment scarce access to which generates land rent this paper first presents some new empirical evidence that in us cities actual employment turns out to be almost as dispersed as residences this range of urban forms is generated with analytic ease in a model that assumes land can have mixed rather than exclusive use at any location the model has firms trading off a central agglomeration force against the lower wages that accompany shorter commuting distances in peripheral locations at one extreme with very high agglomerative forces employment is approximately centered with long commute distances and high congestion levels at the other extreme lower agglomerative forces lead to employment that is completely dispersed commute distances of zero and the absence of congestion maximizing output minus congestion never leads to a pattern of land mixing where employment is fully dispersed a market model however often does if the mix at each location is based on the relative magnitude of the land rent offered from residential as opposed to commercial uses

zoning first best second best and third best criteria for allocating land for roads this paper elaborates on the cost benefit criteria for land uses in an urban setting and on the bias which results from use of market data rather than true shadow prices in the calculation this bias has been discussed extensively in the urban economics literature especially in response to the studies of solow and vickrey 7 and solow 6 progress has been made especially by kanemoto 3 arnott and mackinnon 2 amott l and pines and saclka 151 however because of the different underlying assumptions it is difficult to evaluate and compare some of the seemingly conflicting results reported in these works the purpose of this paper is to reformulate the issues using a systematic exposition to distinguish among various cost benefit calculations and policy regimes and to derive concisely the main results with some useful extensions the cost benefit criteria evaluated in this paper refer to three types of decision making

a temporal and spatial equilibrium analysis of commuter parking abstract this paper examines the effects of parking availability on morning rush hour congestion and assesses the relative efficiency of road tolls and parking fees without pricing drivers occupy parking in order of increasing distance from the cbd a time varying toll can prevent queueing but does not affect the order in which parking spots are taken optimal location dependent parking fees may be superior they do not eliminate queueing but induce drivers to park in order of decreasing distance from the cbd thereby concentrating arrival times closer to work start times competitively set parking fees do nothing to reduce queueing and are relatively inefficient

incorporating land use and pricing policies for reducing car dependence analytical framework and empirical evidence this article develops an analytical framework to connect the theories of market and planning failures with the reasoning of incorporating land use and pricing policies for reducing driving and car

optimal policies in cities with congestion and agglomeration externalities congestion tolls labor subsidies and place based strategies abstract 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

aggregate health care expenditures and national income is health care a luxury good it is well known that a strong relationship exists between national expenditures on health care and national income this has been used to suggest that health care is a luxury good and that factors such as the type of health care delivery system in a country are of little importance in determining expenditure levels this paper argues that these implications rely upon the application of microeconomic analysis to macroeconomic data and that this is not appropriate as well as raising questions about the inferences drawn from previous studies new empirical evidence is presented which casts some doubts on previous findings international comparisons are based on purchasing power parity rather than exchange rate conversions underlining the importance of prices as well as quantities in the relationship and leading to the conclusion that the aggregate data show health care to be if anything a necessity rather than a luxury good

does traffic congestion reduce employment growth abstract this paper examines the impact of traffic congestion on employment growth in large u s metropolitan areas an historic highway plan and political variables serve as instruments for endogenous congestion the results show that high initial levels of congestion dampen subsequent employment growth this finding suggests that increasing the efficiency of public infrastructure can spur local economies counterfactual estimates show that the employment growth returns from modest capacity expansion or congestion pricing are substantial

substitution effects and spatial preference heterogeneity in single and multiple site choice experiments a novel discrete choice experiment dce design allows testing of substitution effects based on the framing of and distances to substitute sites the same ecosystem services and biodiversity provided at different sites are valued independently in single site dces and simultaneously in a multiple site dce using an identical experimental design site specific utility functions are estimated with and without controlling for spatial preference heterogeneity framing choices as alternative projects at single or multiple sites significantly influences substitutability between sites choice behavior and welfare estimates distance decay displays significant heterogeneity in different directions from the valued sites and between urban and rural areas

the attenuation of human capital spillovers abstract this paper uses 2000 census data to estimate the relationship of agglomeration and proximity to human capital to wages the paper takes a geographic approach and focuses on the attenuation of agglomeration and human capital effects differencing and instrumental variable methods are employed to address endogeneity in the wage agglomeration relationship and also to deal with measurement error in our agglomeration and human capital variables three key results are obtained first the spatial concentration of employment within five miles is positively related to wage second the benefits of spatial concentration are driven by proximity to college educated workers an instance of human capital spillovers third these effects attenuate sharply with distance

congestion land use and job dispersion a general equilibrium model abstract in dispersed cities congestion tolls would drive up central wages and rents and would induce centrally located producers to want to disperse closer to their workers and their customers paying lower rents and realizing productivity gains from land to labor substitution but the tolls would also induce residents to want to locate more centrally in order to economize on commuting and shopping travel in a computable general equilibrium model we find that the centralizing effect of tolls on residences dominates on the decentralizing effect of tolls on firms causing the dispersed city to have more centralized job and population densities under stylized parameters we find that efficiency gains from levying congestion tolls on work and shopping travel are 3 0 of average income about 80 of such gains come from road planning and 20 from tolls

urban economic structure technological externalities and intensive land use in china based on theories about the influences of urban economic structure on intensive land use this study analyses the impacts of two main types of urban economic structure in china specialized economy and diversified economy on intensive urban land use using spatial panel techniques and large scale urban panel data the results indicate that there is significant spatial correlation in urban economic structure as well as intensive land use in every city a diversified economy has a significant positive effect on the improvement of intensive land use whereas the effect of a specialized economy is not significant the effects of the diversified and specialized economies on intensive land use through technological externalities are either negative or positive depending on city size while the threshold effect the minimum threshold population for the economy to stimulate intensive land use is about 496 700 people for the specialized economy and about 546 000 people for the diversified economy

congestion tolling with agglomeration externalities abstract consider an urban economy with two types of externalities negative traffic congestion externalities and positive agglomeration externalities deriving from non market interaction suppose that urban travel can be tolled that non market interaction cannot be subsidized and that non market interaction is stimulated by a reduction in travel costs then the optimal toll is below the congestion externality cost this paper explores this line of reasoning

revenue recycling and the welfare effects of road pricing the authors explore the interaction between taxes on work related traffic congestion and preexisting distortionary taxes in the labor market a congestion tax raises the overall costs of commuting to work and discourages labor force participation at the margin when revenues are returned in lump sum transfers the resulting efficiency loss in the labor market can be larger that the pigouvian efficiency gains from internalizing the congestion externality by contrast if congestion tax revenues are used to reduce labor taxes the net impact on the labor supply is positive and the efficiency gain in the labor market can raise the overall welfare gains of the congestion tax by as much as 100 percent recycling congestion tax revenues in public transit subsidies produces a positive but smaller impact on the labor supply in short the authors results indicate that the presence of preexisting tax distortions and the form of revenue recycling can crucially affect the size and possibly even the sign of the welfare effect of road pricing schemes the efficiency gains from recycling congestion tax revenues in other tax reductions can amount to several times the pigouvian welfare gains from congestion reduction

replication in empirical economics the journal of money credit and banking project this paper examines the role of replication in empirical economic research it presents the findings of a two year study that collected programs and data from authors and attempted to replicate their published results the research provides new and important information about the extent and causes of failures to replicate published results in economics the findings suggest that inadvertent errors in published empirical articles are a commonplace rather than a rare occurence copyright 1986 by american economic association

subsidies for intracity and intercity commuting this paper analyzes subsidies for intracity and intercity commuting in an urban economics framework with two cities and agglomeration externalities where workers may commute within and between cities first commuting subsidies serve to internalize agglomeration externalities intracity commuting subsidies give incentives to move to the larger city and intercity commuting subsidies make residents of the periphery commute to the core second if agglomeration rents are locally captured commuting subsidies act as a welfare enhancing transfer from the core to the periphery

the incidence of congestion tolls on urban highways abstract the incidence of an optimal short run congestion toll is investigated using an equilibrium model of modal choice and congestion on a highway corridor served by express bus transit it is argued that for an externality tax the usual equi revenue analysis of burdens is inappropriate instead welfare effects are computed under three alternative assumptions about redistribution of toll revenues in almost all cases the net result is benefits for all income groups it is concluded that congestion tolls should not be rejected on grounds of income distribution but that an explicit package of tolls and revenue uses is probably a political prerequisite for adoption