Portland State University

Even residents of a gingerbread candyland can't get around with holiday magic alone. After all, Santa's elves still need a reliable way to get from their cozy homes to the workshop.

Sadly, transportation planners have turned a frosty shoulder to sugar-based transit systems. Until now.

On Dec. 3, Portland State University's Students in Transportation Engineering and Planning held the first gingerbread transit station competition. Four teams of students pulled their attention away from human transit to focus on the needs of gingerbread people and misfit toys.

Dealing with building materials of unknown structural properties, students field engineered solutions. Licorice sticks stood in for steel rails, candy canes for bicycle racks. For a binding agent, students mixed cream of tartar and egg whites instead of portland cement.

The resulting transit system has already resulted in fewer traffic gum-ups and a drastic reduction in ultrafine powdered-sugar emissions. Sleigh-travel-time reliability has also improved.

Researchers are now assessing the durability of corn-syrup-reinforced composites in candy bridges, the potential for alkali-silica reaction in gingerbread pavement and the possibility that someone hungry will stumble in and eat the infrastructure.

The winning design team was Transit Wonderland, composed of Jesse Boudart, Sara Morrissey, Mark Haines and Meeyonwoo Lim.

The video begins at 3:30.

Abstract: We all use abstractions of reality to help understand the world around us, synthesize knowledge, and to predict the consequences of our actions. These range from ad hoc mental models to highly complex mathematical creations. In this discussion we'll examine the motivations for building formal models, with particular focus on the types of models that will be explored in this course. Several different modeling approaches will be compared, along with the strengths and limitations of each. Some important questions that builders and consumers of models should ask will be covered, as well as ideas for building more useful and informative models. A discussion on how to judge the validity of a model will round out the discussion.

Speaker Bio: Rick Donnelly has over 25 years of experience in the modeling and simulation of transportation systems, from the urban to national level. His current interests include agent-based modeling of freight and logistics, integrated land use-transportation models, and dynamic network modeling. Rick leads the travel modeling and simulation practice at Parsons Brinckerhoff, an international civil and transportation engineering consultancy. He is also a senior fellow at the University of Melbourne, where he earned his doctorate in engineering, and a visiting scholar at Los Alamos National Laboratory.

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View Kristi Currans's slides

View Steve Gehrke's slides

Steven Gehrke, Ph.D. Candidate, Portland State University

Topic: An Activity-related Land Use Mix Construct and Its Connection to Pedestrian Travel

Land use mix is a central smart growth principle connected to active transportation. This presentation describes the indicators of local land use mixing and their association with pedestrian travel in Oregon’s Willamette River Valley. It argues that land use mix is a multidimensional construct reflected by the complementarity, composition, and configuration of land use types, which is positively linked to walk mode choice and home-based trip frequency. Findings from this study underline the conceptual and empirical benefit of analyzing this transportation-land use interaction with a landscape pattern measure of activity-related composition and spatial configuration.

Steven Gehrke is a Ph.D. candidate in Civil and Environmental Engineering at Portland State University. His research examines the transportation-land use interaction,...

The video begins at 1:11.

Abstract: Metro's Transportation Research and Modeling Services Program's (TRMS) is responsible for the development, maintenance, and application of travel demand models for application in long-range planning efforts in the Portland metropolitan region. Representation of traffic -- both vehicular and transit -- plays an integral role in the travel demand modeling process. Complex software is required to assign vehicles and transit users to transportation networks to determine viable options available to travelers, costs associated with those options, and sets of routes by which travelers might navigate their trips. TRMS's current static assignment model has traditionally sufficed for use with Metro's four-step travel demand model. However, static assignments have well documented limitations that preclude the ability of the analyst to answer complex policy questions, especially those related to green house gas emissions, congestion, and transportation network reliability. In addition, static assignments cannot fulfill a need for small duration travel time increments required by the next generation activity-based models. The shortcomings of the static assignment necessitates TRMS's development of regional dynamic traffic assignment (DTA) models. The resolution of these models allows for continuous modeling of traffic over an analysis period, which allows the analyst to capture...