Digital Commons Network^™

Statistical Inference For Multimodal Travel Time Reliability, Avinash Unnikrishnan, Miguel Figliozzi, Subhash C. Kochar

TREC Final Reports

Travel time reliability is a key metric of interest to practitioners and researchers because it affects travel choice and the economic competitiveness of urban areas. This research focuses on three travel time reliability metrics – buffer index, modified buffer index, and the relative width of travel time distributions. The key novel contributions of this research include using the multivariate delta method to prove that the sampling distributions of the three travel time reliability metrics are asymptotically normal. The asymptotic standard error for the three reliability metrics is derived. The asymptotic normality and the standard error result are used to arrive …

Data From: Statistical Inference For Multimodal Travel Time Reliability, Avinash Unnikrishnan, Miguel Figliozzi, Subhash C. Kochar

TREC Datasets and Databases

Travel time reliability is a key metric of interest to practitioners and researchers because it affects travel choice and the economic competitiveness of urban areas. This research focuses on three travel time reliability metrics – buffer index, modified buffer index, and the relative width of travel time distributions. The key novel contributions of this research include using the multivariate delta method to prove that the sampling distributions of the three travel time reliability metrics are asymptotically normal. The asymptotic standard error for the three reliability metrics is derived. The asymptotic normality and the standard error result are used to arrive …

Key Enhancements To The Wfrc/Mag Four-Step Travel Demand Model, Reid Ewing, Sadegh Sabouri, Keunhyun Park, Torrey Lyons, Guang Tian

TREC Final Reports

In a National Transit Institute course on “Coordinating Land Use and Transportation,” co-taught by Robert Cervero, Uri Avin, and the PI on this project, the analytic tools session began with a hypothetical: assume that all households, jobs, and other trip generators are concentrated in a walkable village rather than segregated by use and spread across a traffic analysis zone in the standard suburban fashion. The instructor then asks: How would the outputs of conventional four-step travel demand models differ between these two future land use scenarios. The answer, to most participants’ surprise, was “Not at all.” Conventional four-step travel demand …

Developing Data, Models, And Tools To Enhance Transportation Equity, Amy Lubitow, Raoul Liévanos, Julius Mcgee, Erika Carpenter

TREC Final Reports

This project used a mixed-methods approach to data collection and analysis in the Portland, OR, metropolitan area. It used quantitative techniques, the 2010 Decennial Census, and the 2011 Oregon Household Activity Survey to assess how accurately travel survey data represent minority populations. These groups are of primary interest due to their status as protected classes under Title VI of the Civil Rights Act, and accurate data on the mobility patterns of these groups is essential to equitable transportation planning. Qualitative focus groups with residents in the Portland metropolitan area investigated better methods for building equity into transportation surveys using community …

Making The Seemingly Impossible Project Real Through Local Improvement Districts, Andrew H. Aebi

PSU Transportation Seminars

The planning process identifies community needs but often needs the creative use of financial leverage to make those projects a reality on the ground. Timing is important on Local Improvement District (LIDs), and the window of opportunity is often short.

For Portland's Bureau of Transportation, managing the public's desire for streets in good condition with room to walk and bike safely and accommodating freight movement and population growth can be a tall order. Add in the need to work with water, sewer and underground utilities, and things get complicated.

When needs exceed resources, smart strategies can help fill the gap. …

How Av Could Shape Our Cities - Research From The Netherlands, Gonçalo H. A. Correia

PSU Transportation Seminars

Automated driving has become a hot topic of research in different fields of science. Despite the great advancements in the vehicle technology itself, researchers are now concerned in figuring out what will be the impacts of these vehicles in life as we know it. These impacts can be rather broad from traffic safety to the economy. In this lecture, Goncalo will focus on the research that is being done at TU Delft, a leading university in automated vehicles’ (AVs) impacts research, focusing on urban areas and how mobility, and even the city itself, can change with fully-automated vehicles. Goncalo Correia …

Transferability & Forecasting Of The Pedestrian Index Of The Environment (Pie) For Modeling Applications, Kelly Clifton, Jamie Orrego-Onate, Patrick Allen Singleton, Robert J. Schneider

TREC Final Reports

This project focuses on making our measures, models, and methods more transferable to other locations. Specifically, we re-evaluate, compare and test our pedestrian index of the environment (PIE) measure using data resources more commonly available to planning agencies across the country. Next, we test the results of PIE and its input data in models of pedestrian mode choice for stability of estimation results within a region (intraregional) and between regions (interregional). This research is the next logical step in the MoPeD’s enhancement and is critical to enabling its utility beyond the Portland region. The results of this project show that …

New Pedestrian Modeling Tools: Growing Beyond The Portland Region, Kelly Clifton, Jamie Orrego-Onate, Patrick Allen Singleton, Robert J. Schneider

TREC Project Briefs

This project focuses on making our measures, models, and methods more transferable to other locations. Specifically, we re-evaluate, compare and test our pedestrian index of the environment (PIE) measure using data resources more commonly available to planning agencies across the country. Next, we test the results of PIE and its input data in models of pedestrian mode choice for stability of estimation results within a region (intraregional) and between regions (interregional). This research is the next logical step in the MoPeD’s enhancement and is critical to enabling its utility beyond the Portland region. The results of this project show that …

Pedestrian Observation And Data Collection Curriculum Guide, Jennifer Dill, Tara Beth Goddard

TREC Final Reports

This guidebook provides a comprehensive set of class exercises suitable for students in courses related to travel behavior, traffic safety, urban planning and design, community health, or civil engineering. Exercises include activities developed through this project as well as an extensive set of educational materials drawn from online resources. The exercises developed as part of this project focus on pedestrians. They include elements of both traditional traffic counts and behavioral components, the latter of which are often lacking from current data collections efforts. By encouraging students to consider behavioral interactions of roadway users, these exercises can provide students with field …

Density Differences: Exploring Built Environment Relationships With Walking Between And Within Metropolitan Areas, Jamie Orrego

PSU Transportation Seminars

Part of the Student Presentations from TRB

To explore the relationships between measures of density and walking within and between urban areas, we present an analysis of the travel survey data from six different cities from the US and Santiago, Chile. The analysis of aggregate and disaggregate pedestrian trips presented here examine the potential consistency of relationships between walking and density within and across different regions, with a specific focus on population density. Our findings illustrate a relationship between population density and walk mode shares that is roughly linear and of nearly equal magnitude across US regions in densities below …

One Step At A Time: Counting Pedestrians Students Learn Pedestrian Observation And Data Collection In The Field, Jennifer Dill, Tara Beth Goddard

TREC Project Briefs

This guidebook provides a comprehensive set of class exercises suitable for students in courses related to travel behavior, traffic safety, urban planning and design, community health, or civil engineering. Exercises include activities developed through this project as well as an extensive set of educational materials drawn from online resources. The exercises developed as part of this project focus on pedestrians. They include elements of both traditional traffic counts and behavioral components, the latter of which are often lacking from current data collections efforts. By encouraging students to consider behavioral interactions of roadway users, these exercises can provide students with field …

Focusing On Equity In Regional Plans, Kristine M. Williams

TREC Project Briefs

Metropolitan planning organizations (MPOs) have long been required to consider the equity implications of their regional transportation plans and processes.

Evaluating The Distributional Effects Of Regional Transportation Plans And Projects, Kristine Williams, Aaron Golub

TREC Final Reports

Metropolitan planning organizations (MPOs) have long been required to consider the equity implications of their regional transportation plans and processes. Funded by the National Institute for Transportation and Communities, this research aims to provide additional guidance to MPOs on how to evaluate distributional equity in regional plans and projects. The report begins with an overview of federal requirements related to equity in transportation planning. We then synthesize contemporary methods for measuring transportation equity and the distributional effects of plans and projects from a review of the literature and MPO plans and studies. The report concludes with exploratory case studies of …

A Conceptual Framework For Understanding Latent Demand: Accounting For Unrealized Activities And Travel, Kelly Clifton

PSU Transportation Seminars

Latent demand—the activities and travel that are desired but unrealized because of constraints—have been historically examined from the standpoint of understanding the impacts of proposed capacity or service improvements on travel demand.

Drawing on work from a variety of theoretical perspectives, this paper presents a broader conceptual view of latent demand that provides a useful framework for researching and understanding these unmet needs. This is important from an equity standpoint, as it provides insights into to questions of transport disadvantage, social exclusion and poverty.

The framework presented here is theoretical in nature and untested empirically. This study aims to promote …

Making Every Mode Count In Washington State, Krista Nordback

TREC Project Briefs

A NITC report by Krista Nordback of Portland State University offers a step toward establishing a performance metric by which statewide progress with respect to bicycling and walking can be evaluated. The Washington State Pedestrian and Bicycle Miles Traveled Project discusses the relative merits of three different methods which can be used to compute bicycle miles traveled (BMT) and pedestrian miles traveled (PMT).

Estimating Walking And Bicycling At The State Level, Krista Nordback, Mike Sellinger, Taylor Phillips

TREC Final Reports

Estimates of vehicle miles traveled (VMT) drive policy and planning decisions for surface transportation. No similar metric is computed for cycling and walking. What approaches could be used to compute such a metric on the state level? This report discusses three such approaches, identifies the advantages and disadvantages of each, and applies them to Washington State. The first approach employs travel survey data. The second approach is sample-based using pedestrian and bicycle count data. The third approach is an aggregate demand model approach using demographic data combined with count data. Due to data limitations, none of these methods could be …

Improving Trip Generation Methods For Livable Communities, Kelly J. Clifton, Nico Larco, Kristina Marie Currans, Jael Wettach-Glosser

TREC Final Reports

Recent efforts to improve trip generation data available for transportation impact analysis of new development include the collection of multimodal trip generation data, development of models that account for the built environment, and new recommendations for practice. Building on a long line of research on transportation and built environment, many studies have identified important features of the surrounding built environment that most impact trip rates and mode shares, building on a long line of research on transportation and the built environment. Despite these improvements in data and methods, less attention is placed on identifying the conditions of the site itself …

Improving Trip Data For Livable Communities, Kelly Clifton

TREC Project Briefs

NITC researchers work to refine a framework for trip generation that includes people walking, biking and riding transit.

A Practitioner's Guide To Urban Trip Generation, Kristina Marie Currans

TREC Project Briefs

In 1976, the Institute of Transportation Engineers (ITE) compiled their first Handbook of guidelines for evaluating development-level transportation impacts. Decades later, these methods are still ubiquitously used across the US and Canada. Only recently, with the third edition of the ITE Trip Generation Handbook, have new data and approaches been adopted. In this study NITC researcher Kristina Currans takes aim at understanding issues inherent in the collection and application of ITE’s data and methods in various urban contexts. This technology transfer guide touches on the main findings from this work.

Issues In Trip Generation Methods For Transportation Impact Estimation Of Land Use Development: A Review And Discussion Of The State-Of-The-Art Approaches, Kristina Marie Currans

Civil and Environmental Engineering Faculty Publications and Presentations

As agencies develop more robust planning objectives for creating sustainable and livable communities, the research community has continued developing supportive tools and methods to provide more accurate and robust means for estimating transportation impacts for site-level development review. This paper is a review of the state-of-the-art trip generation methods for land use transportation impact estimation. First, it provides an overview of the more recent available and peer-reviewed estimation methods. Second, the authors offer a discussion of the successes of state-of-the-art approaches using common themes of research to identify corresponding consistency with theories of travel behavior and urban economics. These themes …

Accessibility, Income, And Person Trip Generation: Multilevel Model Of Activity At Food Retail Establishments In Portland, Oregon, Kristina Marie Currans, Kelly Clifton

Civil and Environmental Engineering Faculty Publications and Presentations

In the past decade, the methods for estimating multimodal transportation impacts of urban land use development have improved substantially. One assumption commonly made in these new methods is that overall person-trip rates at similarly-sized establishments of the same land use do not vary across a region. This is an assumption of convenience to permit the adjustment of ITE Trip Generation vehicle trip rates for use in different urban environments. However, this assumption is inconsistent with theories of urban economics, which recognize that businesses pay a premium to locate in areas with high levels of accessibility to attract more customers. In …

Comparing Mode Shares For Non-Residential Destinations In Urban And Suburban Environments, Tasnia Subrin

Student Research Symposium

To ensure facility for multimodal transportation is one of the most important concerns in today’s transportation sector, with initiatives being taken to make multimodal transportation popular. The built environment variables have a strong relationship with transportation mode choice, but whether that relationship holds true in urban and suburban neighborhoods in the same manner has not been considered. Using data for three non-residential land uses, this research explores whether the built environment variables in suburban areas influences mode share like it does in urban areas. We used survey data conducted at the establishments regarding respondents’ travel characteristics from a previous study, …

Webinar: Development Of A Pedestrian Demand Estimation Tool, Kelly Clifton

TREC Webinar Series

Why model pedestrians?

A new predictive tool for estimating pedestrian demand has potential applications for improving walkability. By forecasting the number, location and characteristics of walking trips, this tool allows for policy-sensitive mode shifts away from automobile travel.

There is growing support to improve the quality of the walking environment and make investments to promote pedestrian travel. Despite this interest and need, current forecasting tools, particularly regional travel demand models, often fall short. To address this gap, Oregon Metro and NITC researcher Kelly Clifton worked together to develop this pedestrian demand estimation tool which can allow planners to allocate infrastructure …

How To Estimate Pedestrian Demand, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider

TREC Project Briefs

There is growing support to improve the quality of the walking environment and make investments to promote pedestrian travel. Such efforts often require analytical non-motorized planning tools to estimate levels of pedestrian demand that are sensitive to environmental and demographic factors at an appropriate scale. Despite this interest and need, current forecasting tools, particularly regional travel demand models, often fall short.

To address this gap, Oregon Metro and NITC researcher Kelly Clifton worked together to develop a pedestrian demand estimation tool. For generations, planners have been using statistical models to forecast travel demand, but these models have traditionally been auto-centered. …

Development Of A Pedestrian Demand Estimation Tool, Kelly Clifton, Patrick Allen Singleton, Christopher D. Muhs, Robert J. Schneider

Civil and Environmental Engineering Faculty Publications and Presentations

Most research on walking behavior has focused on mode choice or walk-trip frequency. In contrast, this study is one of the first to analyze the destination choice behaviors of pedestrians. Using about 4,500 walk trips from a 2011 household travel survey in the Portland, OR, region, we estimated multinomial logit pedestrian destination choice models for six trip purposes. Independent variables included terms for impedance (walk-trip distance); size (employment by type, households); supportive pedestrian environments (parks, a pedestrian index of the environment variable called PIE); barriers to walking (terrain, industrial-type employment); and traveler characteristics. Unique to this study was the use …

Development Of A Pedestrian Demand Estimation Tool: A Destination Choice Model, Christopher D. Muhs

PSU Transportation Seminars

There is growing support for improvements to the quality of the walking environment, including more investments to promote pedestrian travel. Planners, engineers, and others seek improved tools to estimate pedestrian demand that are sensitive to environmental and demographic factors at the appropriate scale in order to aid policy-relevant issues like air quality, public health, and smart allocation of infrastructure and other resources. Further, in the travel demand forecasting realm, tools of this kind are difficult to implement due to the use of spatial scales of analysis that are oriented towards motorized modes, vast data requirements, and computer processing limitations.

To …

Using Household Travel Surveys To Adjust Ite Trip Generation Rates, Kristina Marie Currans, Kelly J. Clifton

Civil and Environmental Engineering Faculty Publications and Presentations

The Institute of Transportation Engineers (ITE) Trip Generation Handbook has become the predominant method for estimating vehicle trips generated by development. The handbook is often criticized for its inability to account for multimodal behavior in urban contexts, often overestimating vehicle traffic. The purpose of this research is to develop and test a ready-to-use method for adjusting the ITE handbook vehicle trip generation estimates for urban context. This method was created using household travel surveys from Oregon, Washington, and Maryland, as well as nationally available built environment data. Three adjustments were estimated for eight general land-use categories, including a “pooled” category …

Adjusting Ite’S Trip Generation Handbook For Urban Context, Kelly J. Clifton, Kristina Marie Currans, Christopher D. Muhs

Civil and Environmental Engineering Faculty Publications and Presentations

This study examines the ways in which urban context affects vehicle trip generation rates across three land uses. An intercept travel survey was administered at 78 establishments (high-turnover restaurants, convenience markets, and drinking places) in the Portland, Oregon, region during 2011. This approach was developed to adjust the Institute of Transportation Engineers (ITE) Trip Generation Handbook vehicle trip rates based on built environment characteristics where the establishments were located. A number of policy-relevant built environment measures were used to estimate a set of nine models predicting an adjustment to ITE trip rates. Each model was estimated as a single measure: …

More Urban Form, Fewer Auto Trips, Kelly J. Clifton

TREC Project Briefs

Trip generation refers to the number of vehicle trips that are predicted to originate in a given zone. The Institute of Transportation Engineers (ITE) publishes standard trip generation rates for various land use types, but these rates are primarily measured in low-density suburban areas. There is national interest in building data that expands upon the existing ITE trip generation rates to include sites located in a multi-modal context.

In areas that have a more compact urban form, better access to transit and a greater mix of land uses, fewer vehicle trips may be generated there than ITE rates indicate. However, …

Contextual Influences On Trip Generation, Kelly J. Clifton, Kristina Marie Currans, Christopher D. Muhs

Civil and Environmental Engineering Faculty Publications and Presentations

There is national interest in building data that expands upon the existing Institute of Transportation Engineers (ITE) trip generation rates to include sites located in a multi-modal context. Current ITE rates represent travel behavior for development in single lots and uses, primarily measured in low-density suburban areas. Despite evidence that a more compact urban form, access to transit and a greater mix of uses generates fewer and shorter vehicle trips, local governments are often compelled to use current ITE trip generation rates to evaluate transportation impacts and calculate transportation system development charges (TSDCs). This is due to: a) the expense …