Portland State University

While it’s generally accepted that dense, mixed-use development promotes active travel, researchers don’t have a consensus on exactly how, and to what degree, land use determines people’s travel patterns.

NITC’s latest report, Active Travel Behavior and Spatial-Temporal Land Use Mixing, provides some clarity on the topic.

NITC fellow Steven Gehrke focused his dissertation research on transportation-land use interaction, and sees land use mix as a multidimensional construct.

“We can refocus—away from increasing density—and think more about how we configure land uses,” Gehrke said.

According to Gehrke’s research, more density does not necessarily equal more walking. Rather, the complementarity, composition, and configuration of land use types is essential for cultivating walkability.

Gehrke, who graduates this spring with a Ph.D. in civil and environmental engineering from Portland State University, conducted three empirical studies under his dissertation grant. The first focused on improving measurements of land use mix, introducing a land use mix measurement of the composition and configuration of local land use types.

The second study looked at other smart growth principles, like employment concentration and pedestrian-...

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Many agencies rely on trip generation estimates to evaluate the transportation impacts of land development in urban and suburban areas alike. Over the past decade, substantial attention has been paid to one national set of guidelines—the Institute of Transportation Engineers (ITE) Trip Generation Handbook (2014) and corresponding Manual (2012)—focusing in particular to improve the use of these data and supplementary methods for urban contexts. 

The purpose of this study is to explore the typical data provided in the Handbook, within the context of these new improved state-of-the-art methods. As ITE’s describes, “an example of poor professional judgment is to rely on rules of thumb without understanding or considering their derivation or initial context” (Institute of Transportation Engineers, 2014, p. 3). This research aims to improve the understanding of these data—still ubiquitously used across the US—to encourage increased engagement with their meaning, and following, to provide the users (e.g., engineering, planners, agencies, and developers) with the landscape from which these data were collected and for which they represent. From here, more informed decisions can be made about whether these data provide an adequate or accurate estimation transportation impacts within varying contexts and applications.

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States can reduce greenhouse gas emissions with a broad range of approaches, but none will have much luck without continued support from leaders and the public, according to NITC program research from the University of Oregon. In a conference paper for the annual meeting of the Transportation Research Board in Washington, D.C., a team led by Rebecca Lewis took a close look at the efforts West Coast states have made to reduce emissions from the transportation.

Cutting transportation emissions depends on three variables: vehicle efficiency, fuel carbon content and vehicle miles traveled, or VMT. The paper focuses on the last leg: cutting driving. While more efficient automobiles and alternative fuels have come on the market in recent years, a growing population and longer commutes can wipe out any emissions gains from shifts in fuel economy and fuel type.

Washington, Oregon and California have all passed statutes to cut statewide greenhouse gases below 1990 levels by 2020. The approaches vary in their targets, plans and strategies.

Lewis and her team present the research in a poster session Tuesday, Jan. 12 at the annual meeting of the Transportation Research Board in...

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Recent federal and state policies are placing increasing emphasis on using comprehensive transportation performance measures to guide transportation decision making processes covering policy areas ranging from mobility, safety, economy and livability, to issues of equity and environment. While it is relatively easy to build consensus on mobility measures that center on the transportation system alone, it is much harder for performance measures to incorporate both transportation and land use, loosely defined as accessibility measures, even with continuous efforts to catalog and design such measures.

Two projects at PSU sponsored by Oregon DOT and National Institute of Transportation Communities (NITC) aim to to develop and evaluate Transport Cost Index (TCI), a comprehensive performance measure for transportation and land use, in order to fill important gaps in popular accessibility measures: 

1. TCI is a composite indicator that is able to present an overall picture of a community’s accessibility, while at the same time is relatively easy to interpret for...