UW WSU WSDOT




Current Projects

Right Sizing Low Impact Development (LID) Best Management Practices (BMPs) to Aid in Reducing 6PPD in Stormwater Runoff

Low impact development (LID) best management practices (BMPs) may aim to treat roadway runoff near its source through dispersion and infiltration. These BMPs are crucial for reducing chemicals such as 6PPD and 6PPD-q, which derive from tire preservatives and have been linked to high mortality rates in coho salmon. Unfortunately, WSDOT’s current methods for estimating runoff infiltration rates is believed to be overly conservative, rendering the LID BMPs infeasible and substantially increasing runoff mitigation costs. Runoff infiltration rate is the product of saturated hydraulic conductivity and the hydraulic gradient. The goal of this research is to refine the method WSDOT uses to estimate hydraulic gradients, enabling it to produce more accurate and less conservative estimates of infiltration rates. These refinements should help improve the feasibility, cost-efficiency, and environmental effectiveness of LID BMPs used in WSDOT stormwater designs. This in turn should encourage broader adoption of LID BMPs and help reduce 6PPD-related environmental impacts, particularly in fish-sensitive areas.

Principal Investigators:
Brett Mauer
Mike Gomez
Pedro Arduino
Civil and Environmental Engineering, UW

Sponsor: WSDOT
WSDOT Technical Monitor: Rani Jaafar
WSDOT Project Coordinator: Mustafa Mohamedali
Scheduled completion: May 2027

Laser Scanner Data Collection to Refine Chip Seal Construction Specification

Approximately 7,000 miles of Washington state roadway are paved with chip seals. Chip seals cost less than hot mix asphalt projects and can extend the life of asphalt pavements. The chip embedment depth, or the percentage of chips embedded in the asphalt, plays a crucial role in determining the seal’s performance. Improper chip embedment can lead to raveling, flushing, and bleeding. Unfortunately, there are no specifications governing the required percentage of embedded chips, nor are there data-driven methods available to measure chip embedment depth during construction. In a previous project, the researchers demonstrated the successful use of a laser texture scanner to measure chip embedment depth, and they developed a draft specification for it. This project is collecting field performance data for chip seals that were constructed in 2022 and measured as part of that previous study. With those data the researchers will refine the specification and acceptance criteria for chip seals based on percentage of embedment to be included in the WSDOT Construction Specifications. The resulting specification and measurement method should allow WSDOT to apply chip seals more successfully and cost effectively.

Principle Investigator: Haifang Wen, Civil and Environmental Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Riley Bender
WSDOT Project Coordinator: Shervin Jahangirnejad
Scheduled completion: June 2027

Collaborative Research: Fostering Collective Rationality Among Self-Interested Agents to Improve the Design and Efficiency of Mixed Autonomy Networks and Infrastructure Systems

This Early-Concept Grants for Exploratory Research (EAGER) project is investigating the emergence, mechanisms, and applications of collective rationality among self-interested vehicle agents in the design of mixed autonomy transportation networks and infrastructure systems. Collective rationality refers to the ability of self-interested members of a group to make consistent, logical decisions that maximize overall, shared benefits. This project will explore and rigorously define the concept of collective rationality in the context of mixed traffic and will explore its application to designing the strategic behaviors of autonomous driving agents in mixed autonomy transportation systems. The core hypothesis is that collective rationality can emerge in broad scenarios even if the involved agents are self-interested. The researchers are leveraging game theory and reinforcement learning to verify this hypothesis theoretically and computationally. The results may help reduce travel cost, uncertainties, and fuel emissions, as well as enhance equity among all road users. Broader applications may include autonomous vehicle behavior design and emergency evacuation.

Principle Investigators:
Jia Li, Civil and Environmental Engineering, WSU
Michael Zhang, Civil and Environmental Engineering, UC Davis

Sponsor: National Science Foundation
Scheduled completion: August 2026

Bridging the Gap: Identifying and Addressing Active Transportation Disparities in Underserved Rural Residential Clusters 

Residents of rural residential clusters (RRCs) in Washington often face systemic barriers to safe, affordable, and reliable transportation, resulting in disproportionate hardship and limited access to essential services. The goal of this study is to advance transportation equity by identifying, analyzing, and addressing active transportation (AT) disparities in transportation-disadvantaged RRCs. For this research, an RRC is defined as a small, unincorporated cluster of adjacent homes located along a state highway or major county road. The study area encompasses nine counties in western Washington state, extending from Lewis County northward to the Canadian border. For this project, the researchers are developing a geospatial method for identifying and mapping state and major county roads that prevent residents of RRCs from using AT. They are assessing the specific AT needs, challenges, and perceptions of residents in these communities and are identifying the kinds of infrastructure improvements that would be responsive to local priorities and experiences. They are also developing resources and tools—including a geospatial database, prioritization methodology, and reproducible workflow—to support targeted interventions that WSDOT can implement to improve connectivity, safety, and equitable access for residents of RRCs across the state.

Principal Investigators:
Angela Kitali
Jeff Walters
School of Engineering and Technology, UW Tacoma

Sponsor: WSDOT

WSDOT Technical Monitors:
Grace Young
Brian Wood

WSDOT Project Coordinator: David Strich
Scheduled completion: February 2027

Shore Power: Partnerships to Provide eMobility Options at the Bremerton Ferry Terminal for a Greener Future

Washington State Ferries (WSF) has prioritized electrification as a core strategy to reduce greenhouse gas emissions, improve accessibility, and alleviate congestion at key terminals. This project aims to develop a replicable interagency planning framework for integrating electrified mobility options at ferry terminals. Integrating electric mobility (eMobility) solutions requires a comprehensive approach that includes expanding access to transit, enhancing multimodal travel options, and deploying electrification infrastructure. The Bremerton Ferry Terminal provides a unique opportunity for electrification, given its role as a regional transportation hub with direct connections to Seattle. For this project, researchers are analyzing current mobility challenges, evaluating eMobility and electrification solutions, performing cost analysis and energy demand modeling, creating a scalable planning framework, and engaging stakeholders and facilitating knowledge transfer among WSF, Kitsap Transit, utility providers, and local agencies. The results will support Washington state’s transition to a more resilient, efficient, and equitable transportation system.

Principal Investigators:
Hyun Woo “Chris” Lee, Construction Management, UW
Rachel Berney, Urban Design and Planning, UW
Lingzi Wu, Construction Management, UW
Bart Treece, Mobility Innovation Center

Sponsor: WSDOT
WSDOT Technical Monitor: Kevin Bartoy
WSDOT Project Manager: Mustafa Mohamedali
Scheduled completion: June 2027

Seismic Collapse Prevention for WSDOT Bridges

Earthquakes threaten the functionality and safety of the highway transportation system in Washington state. Given the state’s funding constraints, WSDOT needs to focus scarce resources on the bridge failure mode that is most likely to lead to bridge collapse, namely the shear failure of reinforced concrete columns, and the bridges that are most likely to suffer from column shear failures. This project is developing a new methodology, or modifying an existing one, to evaluate the seismic-shear vulnerability of WSDOT bridges with reinforced-concrete columns.  This will allow WSDOT to account for the amount of shear-strength reduction that will result from repeated cycling during long-duration and shorter-duration earthquakes. The researchers will also provide WSDOT with the practical tools and training needed to implement the developed methodology. The results should enable more reliable characterization of post-earthquake transportation functionality, which will support improved emergency planning. 

Principal Investigators:
Marc Eberhard, Civil and Environmental Engineering, UW
Jeffrey Berman, Civil and Environmental Engineering, UW

Sponsor: WSDOT
WSDOT Technical Monitor: Amy Leland
WSDOT Project Manager: Mustafa Mohamedali
Scheduled completion: October 2027

Sound Mitigation Study of the SR 520 Bridge Modular Expansion Joints, Phase 3

While expansion joints are a necessary component of bridges, they also contribute to noise pollution. Previous studies have investigated the design and feasibility of strategies to mitigate noise caused by modular expansion joints on bridges in Washington state. This study is Phase 3 of an effort to develop a highly durable sound attenuation system in which researchers will perform laboratory-based testing of noise mitigation prototypes. The prototypes will be injected with mixtures of fiber-reinforced, natural, and synthetic rubber with protective additives. The researchers will use a selection of low-density foam to fill gaps for increased durability and protection against roadway debris. Finally, they will use laboratory equipment to evaluate the prototype systems for hydraulic compression, cyclic fatigue, weathering of the system, adhesive durability, abrasion between the prototype and the seal, and susceptibility to debris.

Principal Investigator: Per Reinhall, Mechanical Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Omar Jepperson
WSDOT Project Manager: Mustafa Mohamedali
Scheduled completion: November 2026

Cost-Effective Traffic and Roadway Data Collection Using an Edge-Based, Comprehensive Sensing System: A Machine Learning-Based Approach

High-quality traffic data are crucial for infrastructure planning, system operations and performance measurement, safety considerations, maintenance activities, and informed analysis and decision-making. That’s why state departments of transportation need comprehensive and cost-effective traffic sensing and data collection systems. The primary goal of this research is to develop machine-learning-based detection algorithms, software, and a mobile hardware system that can utilize existing surveillance video cameras to accurately collect critical traffic information that traditional traffic sensors often cannot capture. This information includes vehicle volumes based on FHWA’s 13-bin classification system, speeds, and road surface conditions. The machine learning process will allow the unit to be trained with real data. The major advantage of this new system will be its ability to collect short-duration count data where geometry and volumes pose safety risks to field staff.

Principal Investigator: Yinhai Wang, Department of Civil and Environmental Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Natarajan Janarthanan
WSDOT Project Manager: Doug Brodin
Scheduled completion: December 2025

WSDOT E-bike Incentives

Washington state is preparing to launch WE-bike, an instant rebate program that helps Washington residents purchase certain cycling equipment and electric bicycles, also called e-bikes. In April 2025, people across the state will be able to apply online for one of these instant rebates. Researchers at the University of Washington and Portland State University are partnering to investigate how e-bike incentive programs can change people’s travel choices and how those choices affect greenhouse gas emissions. The project includes researching incentive programs and investigating evaluation designs. The resulting evaluation will, at a minimum, include a survey of a sample of the e-bike incentive recipients approximately one month and six months after their purchase. The survey will also include applicants who applied for an incentive but didn’t get one to better estimate the effects of the incentive on travel behavior, as well as those who were eligible for the incentive but did not apply to better understand barriers to participation. 

Information for those interested in the rebate program and about participating in the UW study can be found on WSDOT’s E-bike Rebate Program FAQ page. WSDOT also hosts a general information page about the E-bike Rebate Program. The WSDOT contact for the rebate program is Adele Peers.

Principal Investigator: Don MacKenzie, Civil and Environmental Engineering, UW
Research Sponsors:
WSDOT
PacTrans

WSDOT Technical Contact: Charlotte Claybrooke
WSDOT Project Manager: Mustafa Mohamedali
Scheduled completion: June 2027

Identification of the Optimal Approach to Maintain Complete Statewide Sidewalk Data

This project aims to facilitate the integration of sidewalk infrastructure data into all Washington State Department of Transportation (WSDOT) processes involving road network data. The focus is on analyses of active transportation and Complete Streets. The scope encompasses assessing inter-agency use needs; establishing requirements for Complete Streets sidewalk data; developing data stewardship and governance protocols, mechanisms, and standards; and defining the requirements for statewide, decision-supporting data tools to allow the display and analysis of walkability based on sidewalk data. The researchers will work with stakeholders and will evaluate their needs. They will inventory software tools and sidewalk data sets currently available. They will also propose methodologies and workflows for consistently displaying walksheds and other common outputs of sidewalk data systems.

Principal Investigator: Anat Caspi, Computer Science and Engineering, UW
Sponsor: WSDOT
WSDOT Technical Monitor: Thomas Craig
WSDOT Project Manager: Jon Peterson
Scheduled completion: June 2026

TRAC