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PSU Transportation Seminar: GHG Inventory from Building Washington State Department of Transportation Roadways

Seminar or Event

Friday Seminars

SPEAKERS

Milad Ashtiani, University of Washington

COST

Free and open to the public

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

THE TOPIC

State departments of transportation (DOTs) are increasingly focusing on reducing greenhouse gas (GHG) emissions, especially with new regulations like the Buy Clean Acts in California, Oregon, and Washington. This project, in collaboration with the Washington State Department of Transportation (WSDOT), aims to assess the agency's carbon emissions through a life cycle assessment of construction materials such as cement, concrete, steel, and asphalt, which are now under heightened scrutiny.

While WSDOT has already implemented strategies to reduce Scope 1 and Scope 2 emissions (related to direct and energy-related activities), there has been limited focus on Scope 3 emissions—those generated upstream in the supply chain. This life cycle assessment reveals that Scope 3 emissions from materials used in WSDOT’s roadways contribute over half of the agency’s total GHG emissions, averaging 310 thousand metric tons of CO2 equivalent annually.

The study emphasizes the critical need to address these emissions and sets ambitious reduction targets for WSDOT: a 50% reduction below 2020 levels by 2030 and a 90% reduction by 2050. These findings and recommendations provide a pathway for WSDOT to lead in sustainable infrastructure practices, aligning with broader transportation goals to mitigate environmental impacts from construction materials.

KEY LEARNING OUTCOMES

State Department of Transportations need better data collection and management approaches to enable greenhouse gas emissions accounting for construction materials.
Scope 3 emissions (mainly in the form of embodied carbon from construction materials) can be as significant as Scope 1 and 2 emissions (i.e., direct emissions from energy use and burning fossil fuels).
Embodied carbon decarbonization strategies for roadways rely heavily on upstream emissions from producing asphalt, concrete, and steel materials.

LOCATION

Vanport Building room 269

Transportation Research at Portland State

TREC research addresses complex transportation problems by drawing on multiple disciplines from across the Portland State University campus. Browse our research areas below, or use the search box at the right to search for a specific project.

Bicycling

A person on a bike rides across a striped cross-bike green and white crosswalk

Portland State University researchers have a broad knowledge of active transportation design principles. Through our Initiative for Bicycle and Pedestrian Design program, we host annual bikeway design workshops which draw professionals from all over the globe, and research from the TREC team has informed NACTO’s Urban Bikeway Design Guide, FHWA’s Bikeway Selection Guide, the FTA’s Manual on Bicycle and Pedestrian Connections to Transit, the FHWA’s Strategic Agenda for Pedestrian and Bicycle Transportation and many other design guidebooks. Our expertise includes protected bike lanes and intersections, bike boulevards, integrating bikes with transit, and more.

See all our projects on bicycling.

Data and Modeling

Data-driven policy and strategy are critical to meeting transportation goals. Where there is insufficient or incomplete data, there can be no effective solutions. It’s why at Portland State University we’ve focused our research efforts over the years on filling data gaps, and why we maintain our transportation data programs. Transportation modeling is a computational approach used to analyze and predict travel behavior, traffic flow, and infrastructure needs. These models help planners and policymakers assess the impacts of new roads, public transit systems, and policy changes on congestion, emissions, and mobility. We conduct research that pushes forward the leading edge of what transportation models are capable of, from creating intelligent, connected transportation systems to using data fusion techniques to improve multimodal transportation. One major research effort under this umbrella focuses on active transportation data fusion.

See all our projects on data and modeling.

E-mobility

Closeup of the seat of an ebike with battery

Electric bicycles (e-bikes), electric cars, e-scooters and other electric vehicles have the potential to significantly lower carbon emissions from the transportation sector. E-bikes in particular offer promising potential to not only reduce carbon emissions, but also improve public health and increase access to active transportation. Research into e-mobility plays a crucial role in advancing sustainable transportation by improving electric vehicle adoption, multimodal infrastructure, and policy frameworks. In particular, e-bikes are one of the most powerful tools in a transportation practitioner's toolbox.

See all our projects on e-mobility.

Economics and Policy

Aerial view of a commercial area

Economics and policy play a fundamental role in shaping transportation systems. Policy drives investment decisions, infrastructure development, and mobility choices, while economic factors often determine what level of access people have to jobs, services, and essential destinations. TREC research explores the economic impacts of different kinds of transportation systems and infrastructure, as well as the economic outcomes of various transportation policy frameworks.

See all our projects on economics and policy.

Equity and Environmental Justice

A factory next to a road

Low-income communities and communities of color often face disproportionate negative outcomes of transportation decisions, such as more exposure to air pollution from highways, limited access to reliable public transit, and displacement from their neighborhoods. Research focused on equity seeks to correct historical disparities by prioritizing investments in public transit, active transportation infrastructure, and clean mobility solutions in traditionally disadvantaged areas. By incorporating equity into transportation policies, cities can create more inclusive systems that promote social, economic, and environmental well-being for all.

See all our projects on equity and environmental justice.

Freight and Logistics

Trucks line up at a weigh station

A strong freight and logistics network is vital for economic growth, resilience, and sustainability. A well-functioning freight system supports supply chains, enabling businesses to operate smoothly, and so plays a critical role in food security, medical supply distribution, and disaster response. PSU research explores various approach to improve logistics and the efficiency of freight transportation.

See all our projects on freight and logistics.

Infrastructure and Resiliency

Tilikum Crossing pedestrian bridge in Portland, Oregon

The strength of a transportation system depends largely on the condition of its infrastructure, from the smallest footpath to the largest freeway. And the bridges serve a crucial role in connecting those transportation systems, carrying traffic over otherwise impassible features. Considering that value, it's doubly important that bridges stand up to earthquakes, especially considering that quakes will disrupt so much else of the built environment. And so research at PSU places a special emphasis on resilience and recovery in those systems. Portland State's InfraStructure Testing and Applied Research Laboratory (iSTAR) tests the resiliency of engineered structures and their materials by reproducing the shaking of real earthquakes.

See all our projects on infrastructure and resiliency.

Land Use and Housing

Aerial view of residential neighborhood

Portland State both reflects and advances a national reputation for considering land use and transportation together. Oregon laws emphasize the importance of transportation and land use in addressing greenhouse gas emissions and our research supports the state in leading this initiative, particularly in the area of modeling and forecasting tools. We examine transit-oriented developments to see their effects on housing, jobs and society, including low-income immigrant communities. We also look at the best ways to balance access to businesses along roadways with the need to avoid conflict between various road users. Our research serves to inform thoughtful access management policy that fosters a vibrant economy and safe road users.

See all our projects on land use and housing.

Safety

Aerial shot of people examining a walking and biking lane

Transportation research on safety aims to protect road vulnerable users. The U.S. Department of Transportation adopts a Safe System Approach as the guiding paradigm to address roadway safety. This holistic approach, using multiple simultaneous strategies, has been embraced by the transportation community as an effective way to make traveling safer for people. Policies promoting safer infrastructure—such as protected bike lanes, pedestrian-friendly streets, and improved transit systems—enhance safety for all users. TREC's safety research evaluates strategies to prevent injuries across all transportation modes.

See all our projects on safety.

Shared Mobility

A row of Biketown bike share e-bikes

Shared mobility refers to transportation services that allow users to access vehicles and transit resources on a shared basis, rather than owning them individually. This can include car-sharing, bike-sharing, ride-hailing (e.g., Uber, Lyft), scooter-sharing, and even shared public transit options like vanpools or microtransit. Shared mobility aims to provide flexible, cost-effective transportation solutions that reduce individual vehicle ownership, lessen traffic congestion, and support sustainable urban mobility by maximizing resource use and reducing environmental impacts.

See all our projects on shared mobility.

Traffic Engineering

A traffic signal

Traffic engineering optimizes the movement of vehicles, cyclists, and pedestrians to enhance safety, efficiency, and sustainability. Our research into traffic engineering explores the design, operation, and management of roadways and intersections, as well as traffic control devices like signals, signs, and pavement markings. This research promotes multimodal planning, prioritizing public transit, biking, and walking to create more equitable and environmentally friendly transportation networks.

See all our projects on traffic engineering.

Transit

A TriMet bus next to a MAX Train

Public transit systems hold promise for serving urban areas safely and efficiently. Yet challenges within transit districts and from outside factors make that service inherently difficult. Research at Portland State has offered insight to transit agencies on planning, operations and safety. And we look at the mixed-use developments designed with access to transit in mind. Our research focuses on the traffic and roadway design that affect transit planning along with operations issues such as keeping vehicles on time and evenly spaced, placing stops where they best serve goals, and scheduling drivers to promote safety and efficiency. It also includes determining which routes best meet community and agency goals and gaining a better understanding of transit users.

See all our projects on transit.

Walking

Pedestrians wait to cross the street at a crosswalk

Everyone is a pedestrian. Our research examines various aspects of pedestrian mobility, safety, infrastructure, and accessibility to improve walkability in urban and suburban environments. By analyzing pedestrian behavior and travel patterns, researchers can develop evidence-based guidelines for the design of safe infrastructure, helping to prevent injuries and enhance equity and accessibility.

See all our projects on walking.