Michael Iacono

Models of Transportation and Land Use Change: A Guide to the Territory

Modern urban regions are highly complex entities. Despite the difficulty of modeling every relevant aspect of an urban region, researchers have produced a rich variety of models dealing with interrelated processes of urban change. The most popular types of models have been those dealing with the relationship between transportation network growth and changes in land use and the location of economic activity, embodied in the concept of accessibility. This article reviews some of the more common frameworks for modeling transportation and land use change, illustrating each with some examples of operational models that have been applied to real-world settings. It then identifies new directions for future research in urban modeling and notes the important contributions of the field to date.

Location, Regional Accessibility, and Price Effects: Evidence from Home Sales in Hennepin County, Minnesota

Regional location factors exert a strong influence on urban property markets, and measures of accessibility are foremost among them. More local influences, such as proximity to urban highway links, also may positively or negatively influence the desirability of a location. This study used a cross section of home sales in Hennepin County, Minnesota, from the years 2001 through 2004, along with a set of disaggregate regional accessibility measures, to estimate the value of access to employment and resident workers. The effects, whether as amenity or disamenity, were estimated for locations near major freeway links that had recently undergone major construction to add capacity (or were scheduled to undergo such construction) at the time of the home sales. The richness of the home sales data set allowed for control of a number of structural attributes, as well as some site characteristics. Additional neighborhood characteristics (such as income levels and local educational quality) were added from supplemental data sources. Empirical results indicated that households highly valued access to employment. Access to other resident workers (i.e., competition for jobs) was considered a disamenity. Proximity to local highway access points associated positively with sale price, whereas proximity to the highway link itself associated negatively with that price. The study concluded with some implications for research and practice of the concept and measurement of the relationship between location and land value.

Predicting Land Use Change How Much Does Transportation Matter

This paper proposes to measure the extent of the influence of transportation systems on land use change. With a set of high-resolution land use data for the Twin Cities, Minnesota, metropolitan region, logistic regression models of land use change are estimated for a 10-year period from 1990 to 2000. The models account for existing land use types, neighboring land uses, and transportation network variables that measure the physical proximity of highway networks, as well as the level of accessibility associated with a specific location. The models are estimated with and without the transportation variables and compared to assess the extent of their influence. Transportation-related variables exert some influence on changes to land use patterns, though not as much as variables representing existing and neighboring land uses.

Accessibility dynamics and location premia: Do land values follow accessibility changes?

The structure of transportation networks and the patterns of accessibility they give rise to are an important determinant of land prices, and hence urban spatial structure. While there is ample evidence on the cross-sectional relationship between location and land value (usually measured from the value of improved property), there is much less evidence available on the changes in this relationship over time, especially where location is represented using a disaggregate measure of urban accessibility. This paper provides evidence of this dynamic relationship using data on home sales in the Minneapolis-St Paul, MN, USA metropolitan area, coupled with disaggregate measures of urban accessibility for multiple modes, for the period from 2000 to 2005. Our investigation tracks the effects of marginal changes in accessibility over time, as opposed to static, cross-sectional relationships, by using an approach in which the unit of observation is a ‘representative house’ for each transportation analysis zone in the region. This approach allows us to control for changes in structural attributes of houses over time, while also isolating the effect of changes in accessibility levels. Results of this approach are compared with a cross-sectional model using the same variables for a single year to illustrate important differences. Empirical estimates indicate that while most of the models estimated using a cross-sectional specification yield positive and significant effects of accessibility on sale prices, these effects disappear when the models are transformed into first-difference form. We explain these findings in light of the state of maturity of urban transportation networks.

Transportation finance, congestion, and equity some policy perspectives

Traffic congestion continues to be a major concern for policy makers and transportation professionals in most large U.S. metropolitan regions. While demand for travel continues to increase, traditional sources of revenue used to finance transportation at the state and local levels are yielding fewer resources (or at least slowing in their rate of growth). As a result, transportation decision makers continue to seek new sources of revenue to finance expansive highway and transit plans. While much effort is expended in seeking adequate revenue sources, little effort is given to determining the equity effects of these new revenue sources, much less the policies they are designed to support. This paper investigates one particular aspect of equity, vertical equity, in relation to transportation finance and policy. Through the use of sets of data (travel demand, financial, and operational) from Minnesota and specifically from the Twin Cities region as illustrations, the authors argue that current policies toward transportation finance and congestion do little to further the interests of low-income individuals and may in fact benefit others at their expense. The authors conclude with some recommendations aimed at redistributing more equitably the burden of financing transportation programs among users and nonusers.

Competitive industry clusters and transportation in Minnesota

Purpose – This study aims to advance the state of knowledge of the relationship between transportation and economic development by investigating how firms in competitive industry clusters use transportation networks and what role those networks play in the competitiveness of these clusters. Design/methodology/approach – The approach combines quantitative and qualitative techniques to geographically identify competitive industry clusters and to investigate the role of transportation. The US Cluster Mapping tool is used to identify competitive clusters by employment location quotients in 25 Minnesota metropolitan and micropolitan regions. A total of 12 competitive clusters were selected for further study, and in-depth interviews and site visits were conducted with businesses in each cluster to explore the competitive importance of different modes of transportation. Findings – Minnesota’s economic competitiveness is dependent on a well-functioning transportation system in all modes – truck, air, rail, and wa...

Methods for estimating the economic impact of transportation improvements: an interpretive review

This chapter reviews several methods of evaluating the economic impacts of transportation improvements. We begin with a discussion of basic project-based methods, such as benefitcost analysis, and discuss some issues which may complicate the accurate estimation of user benefits over the life of a project, especially the dynamic and recursive relationship between transportation networks and land development. We discuss the possible role of capitalized land value changes as an alternate source of estimated user benefits. We then move on to a discussion of regional economic analysis models as a tool for examining the effects of largescale projects or packages of transportation improvements. Their linkages with non-traditional sources of benefits, such as agglomeration effects, and also network effects is considered. Lastly, we consider aggregate analysis methods. These include production function analyses, cliometric studies, and other types of empirical investigations of the relationship between transportation and econometric growth at an aggregate scale. We close by commenting on the merits of each approach, and where and how they might usefully be applied.