Browsing by Subject "Twin Cities (Minnesota)"

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    Access to Destinations: Measuring Accessibility by Automobile
    (Minnesota Department of Transportation, 2010-03) Levinson, David; Marion, Bernadette; Iacono, Michael
    This study describes the development and application of a set of accessibility measures for the Twin Cities region that measure accessibility by the automobile mode over the period from 1995 to 2005. In contrast to previous attempts to measure accessibility this study uses travel time estimates derived, to the extent possible, from actual observations of network performance by time of day. A set of cumulative opportunity measures are computed with transportation analysis zones (TAZs) as the unit of analysis for the years 1995, 2000 and 2005. Analysis of the changes in accessibility by location over the period of study reveals that, for the majority of locations in the region, accessibility increased between 1995 and 2005, though the increases were not uniform. A “flattening” or convergence of levels of accessibility across locations was observed over time, with faster-growing suburban locations gaining the most in terms of employment accessibility. An effort to decompose the causes of changes in accessibility into components related to transportation network structure and land use (opportunity location) reveal that both causes make a contribution to increasing accessibility, though the effects of changes to the transportation network tend to be more location-specific. Overall, the results of the study demonstrate the feasibility and relevance of using accessibility as a key performance measure to describe the regional transportation system.
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    Access to Destinations: Monitoring Land Use Activity Changes in the Twin Cities Metropolitan Region
    (Minnesota Department of Transportation, 2008-07) Iacono, Michael; Levinson, David; El-Geneidy, Ahmed; Wasfi, Rania; Zhu, Shanjiang
    This study presents an effort to track and model land use change in the Twin Cities Metropolitan Region. To that end, we make use of a unique, high-resolution, cell-level set of land use data for the Twin Cities. The data represent 75 meter by 75 meter land use cells, observed at several points in time during the period from 1958 to 2005. These data are used to validate three different types of land use models, which then are used to forecast land use several decades into the future. The models applied in this study include Markov Chain models, Markov Chain-Cellular Automata (MC-CA) models, and an empirical model based on a logistic regression specification. The models are intended to have a simple, transparent structure that allows the user to identify sources of forecast error. Forecasts of land use are made both for the entire study area and also for a specific corridor along State Highway 610 in the northwestern suburbs of the Twin Cities. The study concludes with a brief discussion of the limitations of the models, and how they might meaningfully be expanded and applied.