Portland State University

The video begins at 3:22.

Steve Gehrke (CEE PhD) - Application of Geographic Perturbation Methods to Residential Locations in the Oregon Household Activity Survey: Proof of Concept

Travel demand models have advanced from zone-based methods to favor activity-based approaches that require more disaggregate data sources. Household travel surveys gather disaggregate data that may be utilized to better inform advanced travel demand models and also improve the understanding of how nonmotorized travel is influenced by a household’s surrounding built environment. However, the release of these disaggregate data is often limited by a confidentiality pledge between the household participant and survey administrator. Concerns regarding the disclosure risk of survey respondents to household travel surveys must be addressed before these household-level data may be released at their disaggregate geography. In an effort to honor this confidentiality pledge and facilitate the dissemination of valuable travel survey data, this research: (i) reviews geographical perturbation methods that seek to protect respondent confidentiality; (ii) outlines a procedure for implementing one promising practice, referred to as the donut masking technique; and (iii) demonstrates a proof of concept for this technique on ten respondents to a household activity travel survey in the Portland metropolitan region. To examine the balance...

The video begins at 2:51.

Adam Moore: Bus Stop Air Quality: An Empirical Analysis of Exposure to Particulate Matter at Bus Stop Shelters

Congested traffic corridors in dense urban areas are key contributors to the degradation of urban air quality. While waiting at bus stops, transit patrons may be exposed to greater amounts of vehicle-based pollution, including particulate matter, due to their proximity to the roadway. Current guidelines for the location and design of bus stops do not take into account air quality or exposure considerations. This study compares the exposure of transit riders waiting at three-sided bus stop shelters that either: 1) face the roadway traffic or 2) face away from the roadway traffic. Shelters were instrumented with air quality monitoring equipment, sonic anemometers, and vehicle counters. Data were collected for two days at three shelters during both the morning and afternoon peak periods. Bus shelter orientation is found to significantly affect concentration of four sizes of particulate matter: ultrafine particles, PM1, PM2.5, and PM10. Shelters with an opening oriented towards the roadway were consistently observed to have higher concentrations inside the shelter than outside the shelter. In contrast, shelters oriented away from the roadway were observed to have lower concentrations inside the shelter than outside the shelter. The differences in particulate matter...

Friday Transportation Seminars at Portland State University have been a tradition since 2000. We've opened up PSU Transportation Seminars to other days of the week, but the format is the same: Feel free to bring your lunch! If you can't join us in person, you can always watch online via Zoom.

PRESENTATION ARCHIVE

• Video
• Slides
• PD Certificate

THE TOPIC 

The transportation system in the U.S. has been shaped by a core set of ideas that are embedded in professional practice. These ideas – freedom, speed, mobility, vehicles, capacity, hierarchy, separation, control, and technology – have produced a system in which most people are dependent on driving, with all the negative consequences that entails. Shifting to a system that offers people choices about their daily travel requires a shift in thinking on the part of the transportation profession. In this talk, I take a critical look at...