Elena Safirova

An economic agent-based model of coupled housing and land markets (CHALMS)

This paper describes a spatially disaggregated, economic agent-based model of urban land use, which is named for its innovative feature of coupled housing and land markets (CHALMS). The three types of agents—consumer, farmer and developer—all make decisions based on underlying economic principles, and heterogeneity of both individuals and the landscape is represented. CHALMS simulates the conversion of farmland to housing development over time, through the actions of the agents in the land and housing markets. Land and building structures in the housing bundle are treated explicitly, so the model can represent the effects of land and housing prices on housing density over time. We use CHALMS to simulate the dynamics of land-use changes as a representative suburban area grows. The presence of agent and landscape heterogeneity, stochastic processes, and path dependence require multiple model runs, and the expression of spatial dispersion of housing types, overall housing density, and land prices over time in terms of the most likely, or ‘average’, patterns. We find that CHALMS captures both the general tendency for diminishing population density at greater distances from the center city, and dispersed leapfrog patterns of development evident in most suburban areas of the US.

Welfare and Distributional Effects of Road Pricing Schemes for Metropolitan Washington, DC

Economists have long advocated congestion pricing as an efficient way of allocating scarce roadway capacity. However, with a few exceptions, congestion tolls are rarely used in practice and strongly opposed by the public and elected officials. Although high implementation costs and privacy issues are alleviated as appropriate technologies are developed, the concerns that congestion pricing will adversely affect low-income travelers remain. In this paper, we use a strategic transportation planning model calibrated for the Washington, DC, metropolitan area to compare the welfare and distributional effects of three pricing schemes: value pricing (HOT lanes), limited congestion pricing, and comprehensive congestion pricing. We find that social welfare gains from HOT lanes amount to three-quarters of those from the comprehensive road pricing. At the same time, a HOT lanes policy turns out to be much more equitable than other road pricing schemes, with all income groups strictly benefiting even before the toll revenue is recycled.

What Drives Telecommuting? Relative Impact of Worker Demographics, Employer Characteristics, and Job Types

A 2002 survey of Southern California residents was analyzed to evaluate the relative importance of factors that determined a workers propensity to telecommute and telecommuting frequency. The survey collected a wealth of individual demographic information as well as job type, industry, and employer characteristics from about 5,000 residents. In agreement with previous studies, the propensity to telecommute was found to increase with worker age and educational attainment. At the same time, it was concluded that the propensity to telecommute depended to a large extent on a workers job characteristics and that the quantitative effects of job characteristics were at least as important as demographic factors. The factors that affected telecommuting frequency were also studied based on a 1-week commuting diary of the telecommuters in the survey. The industry and occupation categories that played a significant role in affecting the propensity to telecommute did not have similar effects on telecommuting frequency. On the contrary, some other job-related factors showed substantial influences.

Spatial Development and Energy Consumption

Previous literature has suggested that the urban form (i.e., city size, density, and center distribution pattern) influences urban energy consumption. It has been argued that more dense development is likely to result in more energy-efficient and sustainable cities. However, very little is known about the precise magnitude of possible energy savings from more compact urban form. Moreover, practically no research has been done to investigate which urban policies are likely to be effective in making cities more energy efficient and to quantify those potential energy savings. In this paper we discuss the potential effectiveness of urban policies at improving energy efficiency. First, we analyze several abstract scenarios suggested by the literature to see whether making a previously dispersed city more compact would result in improved energy efficiency. Then we model realistic transportation and land-use policies and examine whether those policies are likely to reduce energy consumption in the urban context.

Marginal Social Cost Pricing on a Transportation Network: A Comparison of Second-Best Policies

In this paper we evaluate and compare long-run economic effects of six road-pricing schemes aimed at internalizing social costs of transportation. In order to conduct this analysis, we employ a spatially disaggregated general equilibrium model of a regional economy that incorporates decisions of residents, firms, and developers, integrated with a spatially-disaggregated strategic transportation planning model that features mode, time period, and route choice. The model is calibrated to the greater Washington, DC metropolitan area. We compare two social cost functions: one restricted to congestion alone and another that accounts for other external effects of transportation. We find that when the ultimate policy goal is a reduction in the complete set of motor vehicle externalities, cordon-like policies and variable-toll policies lose some attractiveness compared to policies based primarily on mileage. We also find that full social cost pricing requires very high toll levels and therefore is bound to be controversial.

Choosing Congestion Pricing Policy

Marginal cost pricing has been long advocated as an efficient way of distributing scarce road resources. In practice, however, policy makers have to retreat to second-best pricing schemes that are associated with lower transaction costs and are simpler for potential users to understand than the first-best marginal cost tolls. To date, the majority of practical applications and theoretical models in Europe and Asia are represented by cordon or area pricing mechanisms, while in North America, variations of link-based tolls have become dominant. This paper compares welfare effects of two second-best cordon pricing schemes with those of second-best link -based tolls for the Washington, D.C., transportation network. START, a strategic and regional transport planning model that features elastic travel demands as well as mode, time period, and route choice, is used to analyze the impacts of the two pricing approaches. Distributional effects of cordon and link-based tolls are also examined in the hope of understa...

Explaining Sprawl with an Agent-Based Model of Exurban Land and Housing Markets

This paper develops a model of land use in a growing community on the urban fringe and uses it to explore the spatial patterns and time path of development. The model is an agent-based model (ABM) of housing and land markets that includes as agents farmer/landowners, a developer who buys land and builds houses, and consumers who purchase housing. Housing is characterized by lot size and house size. As in all ABMs, macro-scale patterns emerge from many micro-scale interactions between individual agents, which are modeled computationally. In contrast to many other ABMs, however, the fundamentals of microeconomic decisionmaking are built into the model — consumers choose houses to maximize utility; farmers compare returns from agriculture to the expected value of their land in development; and developers purchase land and build houses so as to maximize profits. Model simulations reveal some aspects of sprawl such as “leapfrog” development, yet also confirm some results from traditional urban economic models, such as declining density and rent (land price) gradients. Sensitivity analyses on the utility function parameters, the distribution of agricultural productivity, and the travel costs highlight the importance of the economic features of the model.

Choosing Congestion Pricing Policy: Cordon Tolls Versus Link-Based Tolls

Marginal cost pricing has been long advocated as an efficient way of distributing scarce road resources. In practice, however, policy makers have to retreat to second-best pricing schemes that are associated with lower transaction costs and are simpler for potential users to understand than the first-best marginal cost tolls. To date, the majority of practical applications and theoretical models in Europe and Asia are represented by cordon or area pricing mechanisms, while in North America, variations of link-based tolls have become dominant. This paper compares welfare effects of two second-best cordon pricing schemes with those of second-best link-based tolls for the Washington, D.C., transportation network. START, a strategic and regional transport planning model that features elastic travel demands as well as mode, time period, and route choice, is used to analyze the impacts of the two pricing approaches. Distributional effects of cordon and link-based tolls are also examined in the hope of understanding why one scheme might be preferred over another. Because Washington, D.C., in many respects resembles a European city, cordon policies are more likely to be effective there than in more typical North American cities. Although overall net welfare benefits achieved by the three schemes are found to be similar, their dependence on revenue recycling and distributional impacts are quite different. Although the small cordon puts a higher share of costs on low-income travelers than do other pricing schemes, in absolute terms these costs are lower. The exact distributional impact of a larger cordon is uncertain because it depends on the revenue recycling method employed.

Growing Complexities: A Cross-Sector Review of U.S. Biofuels Policies and Their Interactions

In the midst of concerns about U.S. energy security and climate change, a wider use of biomass and biofuels is promoted as one of the recipes for sustainability. The production and use of biofuels in the United States has rapidly increased in the last several years, promoted by a variety of government policies at the federal, state, and even local level. Many of these policies were crafted with focused objectives in mind and are targeted at specific segments of the biofuels market. Little is known, however, about the potential interactions of such policies and whether they are likely to reinforce or negate one another. In this paper, we provide an overview of the most prominent policies to date that impact the production and use of biofuels and biomass and outline their intended objectives and mechanisms. We focus on three economic sectors, electricity, transportation, and agriculture, and conduct a qualitative analysis of selected policy interactions. In particular, we describe hypothetical policy scenarios corresponding to various combinations of policies and analyze their potential outcomes. Finally, we briefly describe the impacts of those policies on other sectors such as food production, energy and environment, infrastructure, and the economy at large.

Distributional Consequences of Public Policies: An Example from the Management of Urban Vehicular Travel

This paper uses a spatially disaggregated computable general equilibrium model of a large US metropolitan area to compare two kinds of policies, “Live Near Your Work” and taxation of vehicular travel, that have been proposed to help further the aims of “smart growth.” Ordinarily, policy comparisons of this sort focus on the net benefits of the two policies; that is, the total monetized net welfare gains or losses to all citizens. While the aggregate net benefits are certainly important, in this analysis we also disaggregate these benefits along two important dimensions: income and location within the metropolitan area. The resulting identification of gainers and losers with these policies, though undoubtedly important to matters such as fairness and political feasibility, are rarely made. We find that these distributional effects are quite sensitive to the details of policy design.