Endogenous job destruction and job matching in cities

We propose a spatial search-matching model where both job creation and job destruction are endogenous. Workers are ex ante identical but not ex post since their jobs can be hit by a technological shock which decreases their productivity. They reside in a city, and commuting to the job center involves both pecuniary and time costs. As a result, workers with high wages are willing to live closer to jobs to save on time commuting costs. We show that, in equilibrium, there is a one-to-one correspondence between the productivity space and the urban location space. Workers with high productivities and wages reside close to jobs, have low per distance commuting costs and pay high land rents. We also show that higher per distance commuting costs and higher unemployment benefits lead to more job destruction.     

Urban agglomeration effects and employment and wage gradients

When employment occurs at both central and non-central points, but firms have a preference to be near the center, the rent gradient will decline, and a wage gradient is necessary to compensate workers for more centrally located employment. Wage gradients and rent gradients are jointly determined. The relationship between wage offer functions and the equilibrium wage gradient is derived, the latter dependent on utility functions and commuting costs. This is illustrated with a two sector model incorporating agglomeration economies in the export sector. Numerical solution reveals how agglomeration economies affect wages, employment, and city size.     

Commuting: In Search of Jobs and Residences

This paper introduces a model which includes residential, job moving, and commuting behavior when labor and housing markets are characterized by market imperfections (imperfect information and moving costs). We examine the consequences of these market imperfections on commuting behavior. An empirical analysis of commuting behavior indicates that workers commute less if they receive more job offers.     

Urban search models under high-relocation costs. Theory and application to spatial mismatch

We develop a search-matching model in which mobility costs are so high that it is too costly for workers to relocate when a change in their employment status occurs. We show that, in equilibrium, wages increase with distance to jobs and commuting costs because firms need to compensate the transportation cost difference between the employed and unemployed workers at each location in the city. We also show that the equilibrium land rent is negatively affected by the unemployment benefit because an increase in the latter induce firms to create less jobs, which, in turn, reduces the competition in the land market. We then use this model to provide a mechanism for the observed spatial mismatch between where black workers live and where jobs are. We finally show that a transportation policy consisting in subsidizing the commuting costs of black workers can increase job creation and reduce unemployment if the level of the subsidy is set at a sufficiently high level.     

The periurban city: why to live between the suburbs and the countryside

The last 30 years have witnessed the emergence of a new pattern of urban development in France, called the periurban belt. It is defined as a belt outside the city occupied both by households and farmers. We develop a residential model in which households commuting to an employment center may choose to live with farmers in this mixed belt because they value the rural amenities created by farming activities. Both types of agents compete on the land market and the equilibrium conditions allow us to obtain an analytical solution and to provide some insights about the robustness of the periurban form against decreases in commuting costs. Finally, the model is calibrated on French data.     

Housing equity,residential mobility and commuting

Highly productive economies require a flexible labor force with workers that move in accordance with the changing demand for goods and services. In times with falling housing prices, the mobility of home owning workers may be hampered by a lock-in effect of low or even negative housing equity. This paper explores the effect of housing equity on both the residential mobility and the commuting pattern of homeowners. We merge administrative registers for the Danish population and properties and get highly reliable micro data for our analysis. We find that low and negative housing equity substantially reduces residential mobility among homeowners. The negative effect of locked-in low equity families on labor market mobility may be mitigated by commuting. However, our results show that family heads in low or negative equity homes are not found to commute more than households with higher housing equity, but also that a considerable fraction of home owning family heads commute. The analysis of the joint decision of homeowners to commute or move shows that the option of moving, as an alternative to not moving and not commuting, is chosen by five to six percent of homeowners with low housing equity, while the option of not moving but commuting is chosen by 60%.     

The commuting time paradox

We examine the conditions for the ‘commuting time paradox’ which states that the average commuting time does not vary between different periods. We develop therefore an equilibrium job search model with endogenously chosen commuting costs. Presuming wage bargaining between workers and firms, the optimally chosen maximum commuting costs jointly maximise the worker's and firm's payoffs. We demonstrate that when productivity levels increase over time, average commuting costs and average wages both increase, which affects the optimally chosen commuting time. We establish the conditions under which the paradox holds.     

The effect of reimbursement of worker's transport costs: The case of urban areas in Japan

In some economies, workers are compensated for their commuting costs to the workplace. The spatial structure of an urban area is analyzed comparing a transport cost compensated system to one where expenses are borne by workers. Profit maximizing behavior by firms results in lower wages being paid in the city where transport costs are compensated. It is shown that worker renters achieve a higher level of utility in the area where transport costs are not compensated. Numerical examples are constructed using a range of parameter values which yields measures of the increase in spatial size of the city where transport costs are compensated. The loss in welfare is also evaluated.     

Does City Structure Affect Job Search and Welfare?

We develop a model in which workers' search efficiency is negatively affected by access to jobs. Workers' location in a city is endogenous and reflects a trade-off between commuting costs and the surplus associated with search. Different configurations emerge in equilibrium; notably, the unemployed workers may reside far away (segregated city) or close to jobs (integrated city). We prove that there exists a unique and stable market equilibrium in which both land and labor markets are solved for simultaneously. We find that, despite inefficient search in the segregated city equilibrium, the welfare difference between the two equilibria is not so large due to differences in commuting costs. We also show how a social planner can manipulate wages by subsidizing/taxing the transport costs and can accordingly restore the efficiency.     

Workforce location and equilibrium unemployment in a duocentric economy with matching frictions

This article examines unemployment disparities and efficiency in a duocentric city where workers are non-uniformly distributed between the two job centers. We introduce commuting costs and search-matching frictions to deal with the spatial mismatch between workers and firms. In a decentralized economy job-seekers do not internalize a composition externality they impose on all the unemployed. With symmetric job centers, a change in the distribution of the workforce can lead to asymmetric equilibrium outcomes. We calibrate the model for Los Angeles and Chicago Metropolitan Statistical Areas. Simulations suggest that changes in the workforce distribution have non-negligible effects on unemployment rates, wages, and net output, but cannot be the unique explanation of a substantial mismatch problem.     

Timing Equilibria in an Urban Model with Congestion

All spatial urban models with congestion assume that the departure (arrival) time of commutes is exogenously determined and assume that travel speed at a given time and location depends upon the traffic density at that point in time and space. This paper presents a framework that encompasses such models, but allows workers to choose the time at which they leave home (arrive at work). This paper then proves that in general only one equilibrium exists for urban models with traditional congestion technology: a commuting pattern in which commuting is continuous and the rush hour never ends, which is unrepresentative of traffic patterns anywhere. This paper concludes by discussing alternative general equilibrium urban models with congestion that may have more realistic equilibria.     

Commuting distances in a household location choice model with amenities

Observed commuting distances generally exceed those predicted by standard models of household location choice. This paper develops a model with locational amenities and two job centers. It is shown that differences in household preferences for amenities can lead to various types of residential location patterns, some of which result in higher average commuting distances in the city.     

基于Mastercam X~6的组合件编程与仿真

文章以旋钮组合零件为例介绍了在加工中心高级工培训中常见的组合件类型,分析组合件特殊的数控加工工艺,合理的选用加工基准、加工顺序和加工方法,对masterCAM X6的自动编程建模方式、加工方法及其加工参数进行探讨,最后生成数控加工刀具轨迹并进行加工仿真。     

Labour supply and commuting time: An empirical study

We estimate a simple labour supply model that incorporates commuting time in a utility maximizing framework. Housing prices are assumed to vary with commuting time, and the elasticity of housing prices with respect to the latter is estimated to be about 10 percent. Using this elasticity estimate the price of commuting time averaged over all individuals is $3.22 while the wage rate is $4.72; thus commuting time is implicitly valued at about two-thirds of the wage rate on average. As far as work hours are concerned, almost all individuals are on the backward bending part of their labour supply curve.     

Inter-city wage differentials and intra-city workplace centralization

We explore the interaction of inter-city and intra-city wage differentials by occupation. The paper makes two main contributions. 1) We construct an occupation-specific index of workplace centralization that accounts for the difference between average employment density from the perspective of employees in each occupation and average employment density from the perspective of all employees. 2) We provide empirical evidence that relative wages of central to non-central occupations increase with city size, or equivalently, the elasticity of wages with respect to city size increases with occupational centrality. We conjecture that this empirical regularity arises because, as city size increases, workers in more central occupations face an increasingly less desirable locus of housing prices and commuting times relative to workers who have jobs in residential areas. The results are robust to the inclusion of individual-specific human capital variables and city-specific fixed effects.     

农民工回乡创业的问题及其政策建议

农民工回乡创业是我国现阶段凸显的一个重要经济社会现象,探讨农民工回乡创业的特点、存在问题、并提出政策建议,具有一定的现实意义。     

Variations in the value of reductions in commuting time

This paper applies the theory of consumer choice to investigate the variations in the value of a marginal reduction in commuting for motorists. Two models are developed: Model I includes leisure and goods in the utility function and Model II adds commuting time to the utility function. Model I predicts that the value of a marginal reduction in commuting time increases as income or commuting time increases and decreases as commuting time saved increases. Model II does not have clear qualitative implications. The empirical tests generally support Model I.     

Who's in charge of the central city? The conflict between efficiency and equity in the design of a metropolitan area

A circular metropolitan area consists of a central city surrounded by a suburb. Households sort over the two jurisdictions based on public service levels and their costs of commuting to the metropolitan center. Using numerical simulations, we show that (1) there typically exist two equilibria: one in which the poor form the voting majority in the central city and the other in which the rich form the majority in the central city; (2) there is an efficiency vs. equity trade-off as to which equilibrium is preferred; and (3) if the central city contains only poor households, equity favors expanding the central city to include rich households. The third result arises not because of a fiscal subsidy from rich to poor households induced by a property tax but rather because of a change in house price capitalization.     

Residential Choice, Mobility, and the Labor Market

There is substantial evidence suggesting that the process of suburbanization creates new job opportunities that are not equally exploited by all workers. In order to explain this phenomenon, a simple model is developed which incorporates borrowing constraints as an important restriction on moving decisions, obstructing the necessary labor flows between jurisdictions required to equalize (net) wages. In essence, people who cannot borrow will be restricted in terms of their capability of changing residence location and therefore will have limited possibilities of working in distant labor markets, or they will be subject to excessive commuting. Furthermore, the labor allocation induced by households' behavior facing these constraints affects consumer welfare, production, and producers' profits. The outcomes with perfect credit markets and with borrowing restrictions are calculated and the economic welfare levels are compared. As wages are flexible, they adjust to reflect the relative scarcity of workers present in each jurisdiction. Consequently, some of the negative effects of the borrowing constraints are compensated, so the outcomes cannot be easily compared. Some numerical examples are constructed to have an idea of the possible outcomes under different conditions. Finally, it is found that allowing for moving cost deductions from taxable income may help to alleviate the problem.     

Estimating the commuting cost and commuting time property price gradients

In this paper, we estimate the property price gradients in Hong Kong. We distinguish our effort from previous studies on the subject by directly measuring the economic distance, i.e., the monetary commuting cost and commuting time, instead of merely the physical distance. Our results are generally supportive of the prediction of a negative property price gradient. In one specification, the estimated capitalization of the savings of commuting cost in property prices appears to be just right. The expected negative effect of commuting time on property values, however, can only be detected among observations with larger commuting times. Nevertheless, over the range where the effect of commuting time has the expected negative sign, the values of time implied by the estimates agree well with the results reported in the transportation economics literature.