Sep 09, 2014

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Topic: Airsage cell phone data and its application in travel modeling
Summary: As part of the initial phase of development for the Idaho Statewide Travel Demand Model, Parsons Brinckerhoff developed a base year auto and truck trip matrix using AirSage cell phone OD data, a statewide network in Cube, traffic counts, and origin-destination matrix estimation (ODME) procedures. To begin, the 4000+ statewide zone system was aggregated into a 700 super zone system for collecting the cell phone OD data. Next, the cell phone data was collected for the month of September 2013 for the following market segments: Average weekday resident HBW, HBO, NHB, and visitor NHB trips. The cell phone trips were then disaggregated to zones using each zone’s share of super zone population and employment. These initial trip matrices were assigned to the daily statewide network using free flow travel time for route impedance and iteratively adjusted to minimize the difference between the estimated link volumes and traffic counts by user class.

This iterative trip matrix balancing procedure, also known as ODME, converged nicely by user class and facility type and produced reasonable flows. The...

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Aug 07, 2014

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Speaker: Joseph Broach, Ph.D. Candidate, Portland State University
Topic: Trick or Treatment? Impact of Route-Level Features on Decisions to Walk or Bike
Summary: Some travel routes attract people walking and cycling, while others may scare them away. What features of street environments are most important, and how do available routes affect decisions to bike or walk on a specific trip? 

Research to date has focused on either large-scale areal measures like "miles of bike lane nearby" or else has considered only shortest path routes. Neither method is suited to capturing the impact of targeted route-level policies like neighborhood greenways. This session will present a new technique for measuring bike and walk accessibility along the most likely route for a given trip. The method is applied to travel data, and results provide new insight into the relationship between route quality and travel mode choice.

Aug 07, 2014

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Topic: Understanding Where We Live and How We Travel: The Development of an Online Visual Survey Tool and Pilot Studies Evaluating Preferences in Residential Neighborhood Choice and Commute

Summary: Understanding changing residential preferences—especially as they are represented within land use and travel demand models—is fundamental to understanding the drivers of future housing, land use and transportation policies. As communities struggle to address a rising number of social challenges with increasing economic uncertainty, transportation and land use planning have become increasingly centered on assumptions concerning the market for residential environments and travel choices. In response, an added importance has been placed on the development of toolkits capable of providing a robust and flexible understanding of how differing assumptions contribute to a set of planning scenarios and impact future residential location decisions.

In this presentation, we discuss one such improvement that can be added to the transportation planning toolkit: an innovative visual online survey tool. This tool was developed to provide a means for...

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Apr 25, 2014

OTREC research from Portland State University has developed a new method of travel demand modeling for pedestrian trips.

Transportation professionals use travel demand modeling to forecast how many people will be using a given portion of the transportation infrastructure. This is typically done using a four-step process, the first step of which relies upon a basic unit known as a transportation analysis zone, or TAZ.

A TAZ is a relatively coarse unit of space that can vary in size depending on planners’ needs; typically it encompasses somewhere around 3,000 residents.

Planners started using TAZs in the 1950s, on mainframe computers with limited capabilities, for guidance in making highway investment decisions. As transportation modeling practice has evolved, computers are capable of processing more data and models are being increasingly relied upon to answer more complex questions. 

Despite growing investment in infrastructure that supports active forms of travel, existing modeling tools often poorly represent the nuances of the pedestrian environment. The project’s principal investigator, Kelly Clifton of Portland State University, explores ways to improve upon the modeling tools currently in existence.

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Feb 21, 2014

Portland State University engineering doctoral student Alex Bigazzi has developed a new course aimed at giving transportation engineers experience running emissions models. The course, Transportation Emissions Modeling, is offered through the Department of Civil and Environmental Engineering.

The practical nature of the course sets it apart from the few emissions courses offered at other universities, Bigazzi said. “Those tend to be on the policy side or the environmental side,” he said. “This is unique in trying to help engineers more than policymakers or future policymakers.”

The course fits with both Bigazzi’s own experience and Portland State’s faculty research strength in emissions and modeling. The university already offers an air quality course, but Bigazzi’s offering focuses narrowly on emissions from motor vehicles.

Students spent the first half of the inaugural course learning context for the models, including when they are used and what they can do. “There are federal requirements to do these models for all serious transportation projects,” Bigazzi said. “People need to understand what goes into them and how accurate they can be.”

Because emissions models aren’t as complex mathematically as other models, and...

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Nov 30, 2012

Portland State University inducted graduate student Kristina Currans into the Denice Dee Denton Women Engineers Hall of Fame in a ceremony Nov. 15. Currans is the second transportation engineering student to win the student award.

Maria Klawe, president of Harvey Mudd College, took the Outstanding Female Engineer honors.

Currans’ boundless enthusiasm and dedication to her work quickly become apparent to anyone who works with her, said Kelly Clifton, an associate professor of civil engineering and director of the Oregon Modeling Collaborative. “I’ve never met someone able to manage so many things,” said Clifton, who nominated Currans for the honor.

Currans works with Clifton as a part of the Oregon Modeling Collaborative and on several OTREC research projects. “She brings a tremendous amount of energy,” Clifton said.

After graduating Oregon State University with a civil engineering bachelor’s degree in 2010, Currans soon made a name for herself in transportation circles. She started her graduate coursework at Portland State and worked during academic breaks with the Oregon Department of Transportation’s Transportation Planning Analysis Unit, home to state and regional transportation models.

“For someone who had just graduated with an undergraduate degree, she completed that internship and really impressed ODOT,” Clifton said. “To do that so quickly caught everyone’s attention.”

Currans tested and worked with the Statewide Integrated...

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Jun 11, 2012

With transportation models increasingly used to inform policy decisions at all levels, OTREC is pleased to offer a free educational series designed to help decision makers, transportation officials and others understand these important tools. The series was organized with OTREC’s Oregon Modeling Collaborative and presented during the weekly transportation seminars at Portland State University’s Center for Transportation Studies.

Archived video of the entire eight-week series is now available. Each seminar lasts one hour. Click here for a description of each seminar and links to the video.

While the Friday seminar series has showcased transportation issues for years, the modeling series marks the first time that eight seminars focused on a single theme. Modeling is a timely topic, as policy makers come to rely increasingly on models, whether or not they have a background in modeling.

The series demonstrates how modeling can support better decision-making and explains the tools and the process to a nontechnical audience, said Kelly Clifton, director of the Oregon Modeling Collaborative. Oregon’s discussions regarding modeling tools have helped inform the national discussion, she said.

The final seminar in the series recapped some of the earlier lessons and pointed out some of the...

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Apr 25, 2012

It’s not shocking that bridges built without thought to earthquakes wouldn’t make it through a big quake unharmed. More surprising, however, is how much damage even a relatively small earthquake would cause to Oregon’s bridges.

In an exhaustive OTREC project, researcher Peter Dusicka looked at the most common bridge types in the Oregon highway system. Those bridges weren’t just fragile, he found—they were even more fragile than other researchers and technical guidelines had suggested.

Dusicka published his preliminary findings in a draft report last year. The final report, “Bridge Damage Models for Seismic Risk Assessment of Oregon Highway Network,” is out now. Click here to download.

Most Oregon highway bridges were built before the 1980s, when designers started to consider seismic activity. Dusicka set out to see what would happen to the most common bridge type, continuous concrete multi-beam or girder, during quakes of varying degrees.

To find that out, he had to first know how the ground in the Pacific Northwest moves during and earthquake and second, model how the bridge type would react to these motions. Historical and geological evidence show a catastrophic earthquake will occur sooner or later in the region, Dusicka has said, as the Cascadia subduction zone stores up energy that will...

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Apr 09, 2012

Although specialized equipment and vehicles make up a large portion of state transportation budgets, an OTREC research report found little consistency in how states decide to replace this equipment.

Researchers David Kim and David Porter of Oregon State University surveyed 25 state departments of transportation to determine how they made replacement decisions. Nearly all consider the age of the vehicle or piece of equipment, with many considering how much use it gets.

Around half use thresholds, such as number of miles or months in service, to identify candidates for replacement. Some consider the equipment’s repair cost or operating cost, while others rely on physical inspections. None explicitly considers greenhouse gas emissions or other environmental concerns in its replacement criteria.

Given the huge range of approaches, Kim and Porter wondered if modeling could lead to better decision-making. They ran various models against the simple approach of using equipment age as a threshold value.

As it turns out, the simple approach isn’t too bad. In fact, it does better than one complicated mathematical model and about the same as a second model.

Click here to learn more about the project and download the report.

That may...

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Apr 06, 2012

Transportation models keep growing more sophisticated. But complicated isn’t necessarily better, Rick Donnelly said during the inaugural seminar in OTREC’s spring 2012 transportation seminar series April 6.

“Better is contextual,” Donnelly said.

Donnelly, who leads the modeling and simulation practice at engineering consultancy Parsons Brinckerhoff, opened the spring seminar series with an introduction to models. Seven more free seminars follow in the series, produced in partnership with the Oregon Modeling Collaborative.

Donnelly detailed questions that model builders and users should ask and offered his thoughts on building more useful and informative models. Click here for a link to the archived presentation.

Although transportation models consider increasingly more information, simpler models can often get the job done with a smaller investment of time and money, Donnelly said. Sometimes the simplest approach actually produces the best results.

“’Better’ is only relevant in the context of what the model is going to be used for,” he said.

The modeling series continues Friday, April 13 with another seminar geared toward non-modelers. The seminar, by Ben Stabler, also of Parsons Brinckerhoff, builds on Donnelly’s opening installment.

Stabler will discuss two approaches to travel modeling and give examples of each approach....

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