Core Researchers

We embrace interdisciplinary research by exploring the unique ways in which transportation intersects with so many aspects of our daily lives. Below are the core of our research faculty and staff, but you can find our comprehensive list of contributors in our Researcher Directory. 


Jason Anderson, Ph.D.
Research Associate, Civil & Environmental Engineering

Jason Anderson is a research associate at Portland State University. Dr. Anderson’s current area of research include: transportation safety modeling, spatial econometrics and statistics, and big data analysis focusing on various concepts (e.g., traffic flow, travel time, freight commodity analyses, methodological approaches, etc.). Dr. Anderson’s methodological expertise offers unique opportunities to conduct research in various fields, including water resources and waste management, construction management, structural engineering, and social/behavior sciences. He is especially interested in emerging technologies and data fusion techniques as it pertains to smart vehicles, infrastructure, cities, and their impacts on safety.

Joseph Broach, Ph.D.
Researcher Modeler, Oregon Metro
Research Associate, College of Urban & Public Affairs

Joseph Broach is a ​Research Associate with the Transportation Research and Education Center (TREC), an Instructor in the School of Urban Studies and Planning at Portland State University, and a Senior Researcher and Modeler at Metro (MPO). H​is work primarily ​focuses ​on transportation data​, behavior,​ and modeling, and ​he ​helped design the ​Portland region's ​next-generation bicycle model in conjunction with Metro.​ 

Joe's research projects include Incorporate Emerging Travel Modes in the Regional Strategic Planning Model (RSPM) ToolTransferability & forecasting of the Pedestrian Index Environment (PIE) for modeling applications, and Travel Mode Choice Framework Incorporating Realistic Bike and Walk Routes.

Kelly Clifton, Ph.D.
Interim Associate Vice President for Research at Portland State University

Dr. Kelly Clifton serves as the interim Associate Vice President for Research at Portland State University, and as a professor in the Department of Civil and Environmental Engineering at Portland State University. She holds an affiliate appointment in the Urban Studies and Planning Program and is a fellow in the Institute for Sustainable Solutions. Her research, teaching and service activities are focused on transportation and how human mobility is shaped by their needs, the built environment, and technology. She is an internationally recognized expert on transport and land use interactions, a 2016 Fulbright Scholar, and major contributor to multimodal modeling.

She has led research efforts into Contextual Influences on Trip Generation, Examining Consumer Behavior and Travel Choices, the Development of a Pedestrian Demand Estimation Tool and more.

Jennifer Dill, Ph.D.
Director, Transportation Research and Education Center (TREC)
Professor, Urban Studies and Planning
Twitter | Website | Researcher Profile 

Dr. Jennifer Dill is a professor in the Nohad A. Toulan School of Urban Studies and Planning at Portland State University (PSU) and Director of the Transportation Research and Education Center (TREC) at PSU. TREC houses the National Institute for Transportation and Communities (NITC), which she also directs. NITC is a national university transportation center funded by the US Department of Transportation focusing on improving mobility for people and goods to build stronger communities. Dr. Dill also serves on the Board of Trustees for the TransitCenter, a New York-based foundation that works to improve public transit in cities across the U.S. Professor Dill is an internationally known scholar researching the relationships between transportation, land use, health and the environment, focusing on active transportation. Before entering academia, Professor Dill worked as an environmental and transportation planner in California. That experience motivates her teaching and research, which aims to inform practice and policy. She has published extensively in peer-review journals and has served as principal investigator or co-PI on over $4.3M in research projects and over $28M in federal center funding. Her research has been covered by Wired, Governing, USA Today, the PBS NewsHour, Here and Now, Marketplace and the Atlantic. She has served on and chaired Transportation Research Board committees and is on the editorial boards of the Journal of Transportation and Health, Transportation Research Record and the Journal of Transportation and Land Use. Professor Dill also serves on the Board of Trustees for the TransitCenter, a foundation that works to improve public transit across the U.S. Prior to entering academia, Dr. Dill worked as an environmental and transportation planner in California. Dr. Dill has a Ph.D. in City and Regional Planning from UC Berkeley, an MA in Urban Planning from UCLA, and a BS in Environmental Policy Analysis and Planning from UC Davis. She is also an aluma of the Eno Future Leaders program.

Notable research projects include Lessons from the Green Lanes: Evaluating Protected Bike Lanes in the U.S., Understanding Types of Cyclists Nationally, Pedestrian Observation and Data Collection Curriculum and more. Read a 2021 interview: Looking Back on Twenty Years of Transportation Research with Dr. Jennifer Dill.

Miguel Figliozzi, Ph.D.
Professor, Civil and Environmental Engineering
WebsiteResearcher Profile 

Professor Figliozzi is the founder and co-director of the Transportation Technology and People (TTP) research lab, as well as a professor of civil and environmental engineering at Portland State University. He is a widely cited scholar and member of the Transportation Research Board Network Modeling Committee and Transportation and Logistics Committee. Figliozzi’s main research areas are transportation systems modeling, statistical analysis, and optimization.

His research investigates the Impact of Advanced Technologies on Livability and Multimodal Transportation Performance Measures in Arterial CorridorsExploiting New Data Sources to Quantify Arterial Congestion and Performance Measures at a Regional Scale, and more.

Aaron Golub, Ph.D.
Director, Nohad A. Toulan School of Urban Studies and Planning
Urban Studies and Planning
TwitterResearcher Profile

Dr. Golub is an associate professor and director of the Toulan School of Urban Studies and Planning at Portland State University. His work focuses on the social equity impacts of current transportation planning practices – how people participate in planning, and who wins and loses from transportation plans and investments. Dr. Golub teaches courses on urban transportation policy, planning research methods, transportation finance and public transportation.

His research explores policy, finance, environmental justice, public transportation, sustainability, bicycle transportation, social change, the Distributional Effects of Regional Transportation Plans and Projects, Applying an Equity Lens to Automated Payment Solutions for Public Transportation, and more.

Hau Hagedorn
Associate Director (TREC)

Twitter | TREC Researcher Profile

Hau Hagedorn is the Associate Director of TREC at Portland State University and is responsible for the day-to-day management, operations and provides overall direction for the TREC's peer-reviewed research and technology transfer programs, and shaping workforce development efforts. She actively participates in national efforts on conducting and implementing research. She also oversees programming and delivery of professional development workshops through the Initiative for Bicycle and Pedestrian Innovation (IBPI). She is co-Chair of the TRB Conduct of Research Committee, Chair of the Oregon Bicycle and Pedestrian Advisory Committee (OBPAC), and member of the Region 1 Area Commission on Transportation (R1ACT). Hau has over 20 years of public and private sector experience in transportation. 

Her research includes an investigation of the Policy Implications of ORS 366.514 - The Oregon Bike Bill and the ongoing development of the bicycle and pedestrian data clearinghouse BikePed Portal.

Sirisha Kothuri, Ph.D.
Senior Research Associate, Maseeh College of Engineering and Computer Science

Sirisha Kothuri, Ph.D. is a senior research associate in the Department of Civil and Environmental Engineering at Portland State University. Dr. Kothuri’s primary research interests are in the areas of multimodal traffic operations, bicycle and pedestrian counting, and safety. Dr. Kothuri is the research co-chair of the Transportation Research Board’s Pedestrians Committee (ANF10) and the Bicycle and Pedestrian Data Subcommittee (ABJ 35(3)) and a member of Traffic Signal Systems committee. Dr. Kothuri received her BCE from Osmania University, India, MSCE from Louisiana State University, Baton Rouge and Ph.D. from Portland State University.

Dr. Kothuri's research includes investigations into Incorporating Pedestrian Considerations into Signal TimingImproving Walkability Through Control Strategies at Signalized IntersectionsAddressing Bicycle-Vehicle Conflicts with Alternate Signal Control Strategies and Improving Bicycle Crash Prediction.

Jenny Liu, Ph.D.
Associate Professor, Urban Studies and Planning

Jenny Liu is an associate professor of urban studies and planning at Portland State University. She is an environmental and resource economist with a focus in transportation economics. Her research interests include the economics of alternative energy sources, links between transportation choices and environmental issues, the effects of physical infrastructure networks and social networks on the adoption of transportation technologies, and technology adoption and its effects on climate change, particularly within the urban and development contexts.

Dr. Liu's research has looked into Understanding the economic impacts of urban greenway infrastructureMeasuring the Impacts of Social Media on Advancing Public Transit, and the Economic and Business Impacts of Street Improvements for Bicycle and Pedestrian Mobility.


John MacArthur
Sustainable Transportation Program Manager, Transportation Research & Education Center (TREC)

Mr. John MacArthur is the Sustainable Transportation Program Manager at TREC at Portland State University and an instructor in civil and environmental engineering, teaching on new & emerging technologies in transportation. He is active in research related to sustainable and equitable transportation, particularly in the areas of emerging tech such as e-bikes, bike share, transit, and the relationship between transportation and public health. Mr. MacArthur is the Section Chair for Transportation Research Board’s AME00 Transportation and Society and a member of Innovative Public Transportation Services and Technologies (AP020). He received his BS in Civil Engineering from Lehigh University and a MS in Environmental Health Sciences from the School of Public Health at the University of Michigan.

MacArthur is the Principal Investigator for TREC's electric bicycle research initiatives. His research also includes low-/no-emission vehicle infrastructure in Portland metro, as well as a climate change impact assessment for surface transportation in the Pacific Northwest and Alaska. Before joining the TREC staff, John was the Context Sensitive and Sustainable Solutions Program Manager for the Oregon Department of Transportation’s OTIA III State Bridge Delivery Program.

Nathan McNeil
Research Associate, College of Urban & Public Affairs

Nathan McNeil is a Research Associate at Portland State University's Center for Urban Studies. He conducts research on impacts of active transportation and transit equity, on new bicycle infrastructure and programs on travel behavior and attitudes towards cycling, on shared-use mobility programs including carsharing and bike-share, and on the connection between land-use and transportation. He was Co-Principal Investigator on recent national studies of bike share equity (Breaking Barrier to Bike Share and National Scan of Bike Share Equity Programs) and of protected bike lane implementations (Lessons from the Green Lanes). Nathan received a master of urban and regional planning from Portland State University (PSU) and studied history at Columbia University as an undergraduate. Prior to PSU, Nathan worked for the Metropolitan Transportation Authority in New York City as a performance auditor where he evaluated capital programs and contractors.

Nathan's research has looked into Evaluating Efforts to Improve the Equity of Bike Share SystemsContextual Guidance at Intersections for Protected Bicycle Lanes and Bicycle and Pedestrian Traffic Monitoring Data Quality, among others. He also worked on the FTA Manual on Pedestrian and Bicycle Connections to Transit, published in 2017.

Christopher Monsere, Ph.D.  
Department Chair & Professor, Civil and Environmental Engineering

Dr. Christopher M. Monsere is Professor and Chair of Civil and Environmental Engineering in the Maseeh College of Engineering & Computer Science at Portland State University. Dr. Monsere's primary research interests are in design and operation of multimodal transportation facilities including user behavior, comprehension, preferences, and the overall safety effectiveness of transportation improvements. Dr Monsere is a member of ANF20, the Bicycle Transportation Committee, the past co-chair of the Transportation Research Board's Safety Data, Analysis, and Evaluation committee (ANB20) and a past member of the TRB Task Force to develop the Highway Safety Manual (ANB25T). Monsere received his BCE from the University of Detroit Mercy; his MSCE and Ph.D.with an emphasis in transportation from Iowa State University. Dr. Monsere is a licensed professional engineer in the state of Oregon.

Dr. Monsere's research efforts include Improving Walkability Through Control Strategies at Signalized IntersectionsImproving Adaptive Response Signal Control Performance, and Effective Design Treatments for Right-Turns at Intersections with Bicycle Traffic .

Kristin Tufte, Ph.D.
Research Assistant Professor, Department of Computer Science

Dr. Kristin Tufte has over 25 years experience in data architecture and data management system design and performance and 15 years experience in transportation data management. Dr. Tufte directs PORTAL — a 17TB archive of freeway, transit and traffic signal data which provides visualizations of performance measures for transportation professionals. Dr. Tufte was on teams that implemented two groundbreaking data management systems — a parallel geo-spatial data management system sold to NCR corporation and a data stream management system — technologies from both systems are now commonplace in the data management industry. In addition to her research work, Dr. Tufte teaches data management courses at Portland State University.

Her research encompasses work on BikePed Portal, TREC's Online Non-motorized Traffic Count Archive, and improved methods for Biking and Walking Quality Counts: Using “BikePed Portal” Counts to Develop Data Quality Checks.

Avi Unnikrishnan, Ph.D.
Professor, Civil and Environmental Engineering

Avi Unnikrishnan is a David Wedge Vision Professor of Civil and Environmental Engineering at the Maseeh College of Engineering & Computer Science at Portland State University, and member of the Transportation Research Board (TRB) Network Modeling Committee, Traffic Flow Theory Committee, and the ASCE Intermodal and Logistics Committee. Avi has contributed to Stochastic and Dynamic Hyperpath Equilibrium Models, Preventing End of Queue Accidents, and the development of a transportation undergraduate research fellowship, a program designed to equip engineering undergraduate students with critical thinking and research skills relevant to transportation engineering and planning with a livability theme.

His research projects include Statistical Inference for Multimodal Travel Time Reliability, the development of Real-Time Stochastic Matching Models for Freight Electronic Marketplace, and Methodologies to Quantify Transit Performance Metrics at the System-Level

Liming Wang, Ph.D. 
Associate Professor, Urban Studies and Planning

Liming Wang is an assistant professor in PSU's Toulan School of Urban Studies & Planning. He teaches courses in Travel Demand Modeling, Transportation and Land Use, and Data Analysis Methods. His research takes a data-driven approach to address challenging issues in planning, in particular those intersecting land use and transportation. His recent research projects include data integration techniques for transportation and land use modeling, development and evaluation of comprehensive performance measures for transportation and land use systems, and regional strategic planning tools.

Dr. Wang has conducted research on Continuous Data Integration for Land Use and Transportation Planning and ModelingEvaluating and Enhancing Public Transit Systems for Operational Efficiency, Service Quality and Access Equity, and the development of a data science course, Introduction to Scientific Computing for Planners, Engineers, and Scientists.