All posts by trac

Washington State Rest Area Site Evaluation Study

Washington state has 42 safety rest areas. These rest areas differ in their capacity, facilities, and accessibility in each traffic direction. Some are located at the most traffic-dense corridors such as I-5 and I-90, whereas others are on less traffic-dense state routes. This project provided information on Washington rest area use and user experiences and evaluated the impacts of rest areas on traffic safety.

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Ensuring Stream Stability with the Use of Organic Material in a Flume—Design Recommendation

Fish populations in the Pacific Northwest have declined as spawning grounds have disappeared because of river and stream barriers, often under-road culverts. This research investigated ways to incorporate different kinds of organic material inside a culvert that would both maintain the stream channel shape while also improving the ability of fish to successfully navigate those culverts during low water flow.

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Equity Analysis of WSDOT’s Toll Program

The Washington State Department of Transportation (WSDOT) uses tolling as a key mechanism for managing demand on I-405, SR 167, SR 99, SR 16, and SR 520 and for funding megaprojects on those facilities. Tolls impose an expense on roadway users, and imposition of these fees can raise concerns about equity. This project provided insight into the use of WSDOT’s toll facilities that is intended to serve as the basis for evaluating the equity implications of those toll facilities.

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Maintenance of the Active Transportation Elements of Complete Streets

The need for maintenance of active transportation facilities is relatively new, and the development of consistent levels of service and treatment intervals for all aspects of these facilities is just emerging. This project explored the challenges and opportunities associated with maintaining these facilities, with particular emphasis on lanes that serve bicyclists.

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Applications for Foamed Glass Lightweight Aggregate

Recycled and lightweight fill materials are increasingly used in construction because they can address challenging site conditions, accelerate project timelines, and reduce reliance on natural resources while contributing to an agency’s sustainability goals. This project investigated the use of one such material, foamed glass aggregate, for the Illinois State Toll Highway Authority.

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Impacts of Cascadia Subduction Zone M9 Earthquakes on Bridges in Washington State: Three-Dimensional Bridge Models

The performance of bridges during large-magnitude earthquakes generated by the Cascadia Subduction Zone is an essential feature of the resilience of communities along the U.S. West Coast because bridges will be needed for pre-tsunami evacuation, emergency response, and economic recovery. This project developed a three-dimensional, nonlinear model of a typical bridge and subjected it to sets of simulated magnitude 9.0 earthquake ground motions to investigate the performance of bridges with a variety of structural characteristics.

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Simulation Environment to Optimize Public Investments in Electric Vehicle Charging Infrastructure

Plug-in electric vehicle registrations have increased rapidly in Washington state. While most charging can be done at home for low cost, long-distance travel requires fast chargers that can deliver a charge while drivers take a short break. This study developed a simulation model to recommend where electric vehicle fast charging stations would be most useful to help WSDOT staff prioritize investments in fast charging infrastructure.

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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