Transportation Commons^™

Current Vehicle Fleet Inventory And Future Implementation Of A Centralized Electric Fleet At Portland State University, Dane Kovaleski

Environmental Science and Management Professional Master's Project Reports

As the effects of climate change continue to impact the world, many institutions have developed climate action goals to reduce their effects on the environment. Portland State University (PSU) has committed to an 80% reduction of greenhouse gas emissions by 2030 and carbon neutrality by 2040. A part of this commitment must include looking at the contributions of transportation on campus to reduce carbon emissions. According to a greenhouse gas emissions report done by the Campus Planning and Sustainability Office in 2016, transportation contributed to 12% of total greenhouse gas emissions on campus.

This project aims to evaluate the management …

Extending The Service-Life Of Bridges Using Sustainable And Resilient Abutment Systems: An Experimental Approach To Electrochemical Characterization Of Lightweight Mechanically Stabilized Earth, Fariborz M. Tehrani, Kenneth L. Fishman, Farmehr M. Dehkordi

Mineta Transportation Institute

Bridges are critical components of transportation infrastructure. This research addresses the need to extend the service life of bridges by improving the safety and reliability of bridge abutments and reducing their life-cycle cost and footprints. Mechanically stabilized earth (MSE) is a known strategy to enhance the economy and performance of bridge abutments. In addition, the application of rotary-kiln-manufactured lightweight aggregate backfills improves the performance of MSE bridge abutments with a leaner structural system. Such improvements include a reduction of structural demands due to a lower density, free drainage of granular materials, a high internal friction angle, less settlement with no …

Electrical Vehicle Charging Infrastructure Design And Operations, Yu Yang, Hen-Geul Yeh

Mineta Transportation Institute

California aims to achieve five million zero-emission vehicles (ZEVs) on the road by 2030 and 250,000 electrical vehicle (EV) charging stations by 2025. To reduce barriers in this process, the research team developed a simulation-based system for EV charging infrastructure design and operations. The increasing power demand due to the growing EV market requires advanced charging infrastructures and operating strategies. This study will deliver two modules in charging station design and operations, including a vehicle charging schedule and an infrastructure planning module for the solar-powered charging station. The objectives are to increase customers’ satisfaction, reduce the power grid burden, and …

Imitation Improvement Learning For Large-Scale Capacitated Vehicle Routing Problems, The Viet Bui, Tien Mai

Research Collection School Of Computing and Information Systems

Recent works using deep reinforcement learning (RL) to solve routing problems such as the capacitated vehicle routing problem (CVRP) have focused on improvement learning-based methods, which involve improving a given solution until it becomes near-optimal. Although adequate solutions can be achieved for small problem instances, their efficiency degrades for large-scale ones. In this work, we propose a newimprovement learning-based framework based on imitation learning where classical heuristics serve as experts to encourage the policy model to mimic and produce similar or better solutions. Moreover, to improve scalability, we propose Clockwise Clustering, a novel augmented framework for decomposing large-scale CVRP into …

A Data-Driven Approach For Scheduling Bus Services Subject To Demand Constraints, Brahmanage Janaka Chathuranga Thilakarathna, Thivya Kandappu, Baihua Zheng

Research Collection School Of Computing and Information Systems

Passenger satisfaction is extremely important for the success of a public transportation system. Many studies have shown that passenger satisfaction strongly depends on the time they have to wait at the bus stop (waiting time) to get on a bus. To be specific, user satisfaction drops faster as the waiting time increases. Therefore, service providers want to provide a bus to the waiting passengers within a threshold to keep them satisfied. It is a two-pronged problem: (a) to satisfy more passengers the transport planner may increase the frequency of the buses, and (b) in turn, the increased frequency may impact …

Vehicle Rebalancing In A Shared Micromobility System With Rider Crowdsourcing, Ziliang Jin, Yulan Wang, Yun Fong Lim, Kai Pan, Zuo-Jun Max Shen

Research Collection Lee Kong Chian School Of Business

Problem definition: Shared micromobility vehicles provide an eco-friendly form of short-distance travel within an urban area. Since customers pick up and drop off vehicles in any service region at any time, such convenience often leads to a severe imbalance between vehicle supply and demand in different service regions. To overcome this, a micromobility operator can crowdsource individual riders with reward incentives in addition to engaging a third-party logistics provider (3PL) to relocate the vehicles. Methodology/results: We construct a time-space network with multiple service regions and formulate a twostage stochastic mixed-integer program considering uncertain customer demands. In the first stage, the …

Investing In California’S Transportation Future: 2022 Public Opinion On Critical Needs, Asha Weinstein Agrawal, Hilary Nixon

Mineta Transportation Institute

This study surveyed 3,821 adults living in California about their general travel behaviors and resources, use of ride-hailing, performance ratings for the transportation system and agencies responsible for transportation, transportation system improvement priorities, and preference for how transportation funds are allocated. Key findings include the following: • Californians are multi-modal: Although driving was the most common mode, respondents reported that in the previous 30 days 66% had made a walk trip, 28% had used ridehailing, 25% had used public transit, and 22% had bicycled. • Although many respondents had at least once substituted ride-hailing for transit, walking, or bicycling and …

Estimation Of Recursive Route Choice Models With Incomplete Trip Observations, Tien Mai, The Viet Bui, Quoc Phong Nguyen, Tho V. Le

Research Collection School Of Computing and Information Systems

This work concerns the estimation of recursive route choice models in the situation that the trip observations are incomplete, i.e., there are unconnected links (or nodes) in the observations. A direct approach to handle this issue could be intractable because enumerating all paths between unconnected links (or nodes) in a real network is typically not possible. We exploit an expectation–maximization (EM) method that allows dealing with the missing-data issue by alternatively performing two steps of sampling the missing segments in the observations and solving maximum likelihood estimation problems. Moreover, observing that the EM method could be expensive, we propose a …

A Lightweight Privacy-Preserving Path Selection Scheme In Vanets, Guojun Wang, Huijie Yang

Research Collection School Of Computing and Information Systems

With the rapid development of edge computing, artificial intelligence and other technologies, intelligent transportation services in the vehicular ad hoc networks (VANETs) such as in-vehicle navigation and distress alert are increasingly being widely used in life. Currently, road navigation is an essential service in the vehicle network. However, when a user employs the road navigation service, his private data maybe exposed to roadside nodes. Meanwhile, when the trusted authorization sends the navigation route data to the user, the user can obtain all the road data. Especially, other unrequested data might be related to the military. Therefore, how to achieve secure …

Testing Automated Driving Systems By Breaking Many Laws Efficiently, Xiaodong Zhang, Wei Zhao, Yang Sun, Jun Sun, Yulong Shen, Xuewen Dong, Zijiang Yang

Research Collection School Of Computing and Information Systems

An automated driving system (ADS), as the brain of an autonomous vehicle (AV), should be tested thoroughly ahead of deployment. ADS must satisfy a complex set of rules to ensure road safety, e.g., the existing traffic laws and possibly future laws that are dedicated to AVs. To comprehensively test an ADS, we would like to systematically discover diverse scenarios in which certain traffic law is violated. The challenge is that (1) there are many traffic laws (e.g., 13 testable articles in Chinese traffic laws and 16 testable articles in Singapore traffic laws, with 81 and 43 violation situations respectively); and …

Traffic-Related Pedestrian Deaths In The Mountain West, 2022, Miguel Soriano Ralston, Caitlin J. Saladino, William E. Brown Jr.

Transportation & Infrastructure

This fact sheet examines data from Smarth Growth America’s report, “Dangerous By Design, 2022,” which reports on traffic deaths throughout the United States. This fact sheet highlights pedestrian deaths as well as deaths among specific groups based on age, race, ethnicity, and media household income between 2016 and 2020 in the Mountain West: Arizona, Colorado, Nevada, New Mexico, and Utah. This fact sheet builds upon a 2020 fact sheet, titled “Traffic-Related Pedestrian Deaths in the Sun Belt Region,” which examined Smart Growth America’s assessment of pedestrian safety for the years 2008 to 2017.

Webinar: Transportation Resources And Behaviors Among Older Immigrants And Migrants, Rebecca Mauldin, Stephen Mattingly, Rupal Parekh

TREC Webinar Series

This presentation reports findings from a cross-sectional survey of older Vietnamese immigrants in the Dallas-Fort Worth, TX metroplex and members of a Hispanic senior center in Hartford, CT. In addition to providing a description of transportation resources and behavior, we present a method for assessing the geospatial "regular activity spaces" of older adults based on the frequency and locations of routine activities. We also present options for assessing the geospatial burden of providing rides to older adults using "ride-provision activity spaces," which entails the frequency and locations of activities for which rides are given. Finally, we discuss the association of …

Transportation Behavior Among Older Vietnamese Immigrants In The Dallas-Fort Worth Metroplex: Well-Being, Geospatial Mobility, And Potential Indicators For Ride Providers’ Geospatial Burden, Rebecca L. Mauldin, Stephen Mattingly, Mahshid Haque, John P. Connolly, Latisha Thomas, Zachary Tarbet, Farzana Chowdhury, Rupal Parekh

TREC Final Reports

Nearly 4.6 million immigrants aged 65 and older live in the United States. This population is expected to more than triple in size by 2050. A lack of culturally appropriate transportation solutions for older immigrants creates disparities in access to services for older immigrant populations, increasing their risk of social isolation and reduced physical and mental health. A growing number of older immigrants live in low-density urban environments, which are characterized by high automobile dependency and limited public transportation. In these environments, older immigrants are likely to depend on others to provide private transportation. Negative aspects of this reliance on …

Pavement Condition Survey Using Drone Technology, Lerose Lane, Dingxin Cheng

Mineta Transportation Institute

Timely repairs of pavement defects are essential in protecting both public road and highway systems. Identification of pavement distresses is necessary for planning pavement repairs. This has previously been performed by engineers surveying the roadways visually in the field. As drone usage has progressed, it has become clear that drones are a valuable tool to enhance visual documentation, improve project communication, and provide various data for processing. The use of drone technology has improved both the speed and accuracy of capturing data. Available software has allowed the data to be processed and analyzed in an office environment. This report summarizes …

Sustaining Multimodal Choices: Examining Travel Behavior For Non-Work Trips Beyond Covid-19, Yizhao Yang, Rebecca Lewis

TREC Final Reports

Increasing the usage of sustainable travel modes requires changes in both environmental and psychological dimensions. A knowledge gap exists concerning the mechanism via which various factors interact to shape travel decision. Gaining such knowledge requires our ability to examine people’s behavioral adjustment in reaction to environmental and psychological changes or interventions.

This project uses COVID-19 as a natural experiment, treating the significant disruption induced by the pandemic as an intervention to study changes in travel behaviors and adoption of different travel choices following the COVID pandemic. This project builds upon a 2020 study conducted by the PI’s. It adopts a …

Economic Evaluation Of Route Choice Characteristics For Company Truck Drivers And Owner-Operator Truck Drivers In Southern California Freeways, Joseph J. Kim, Jose Alejandro Arroyo Turcios

Mineta Transportation Institute

To contribute to the understanding of freeway capacity and financing options, this study evaluates the demand for truck-only toll lanes on Southern California freeways. The study implemented surveys to both company truck drivers and owner-operator truck drivers to estimate the value they place on time, reliability, and safety measures. The research team met face-to-face with both types of truck drivers near the Ports of Los Angeles and Long Beach to understand the drivers’ perspectives regarding truck-only toll lanes on Southern California freeways. A data set containing 45 surveys out of 62 survey responses were used for statistical analysis. The results …

Curriculum Evaluation Of The Academy Of Global Logistics Program: Connections To Stem Education, Ann Y. Kim, Tyler Reeb, Jaylee Jordan, Youngjin Song

Mineta Transportation Institute

The Academy of Global Logistics (AGL) is a career technical education program developed in collaboration with the Port of Long Beach and the Long Beach Unified School District and with support from the Center for International Trade and Transportation. Students enrolled in the program, implemented at a high school in Long Beach, CA, learn global logistics and supply chain management over the course of their high school career. The program culminates in a capstone project that is evaluated by industry leaders. This research project applies qualitative coding methods to find connections between the AGL curriculum and CA mathematics and science …

Enhancing Older Adults’ Mobility In Active Living And Tiered Living Communities, Yongping Zhang, Carol Kachadoorian, Wen Cheng, Edward Clay

Mineta Transportation Institute

The U.S. population is aging rapidly. As people get older, they increasingly face issues such as increased susceptibility to injuries and the need to be assisted with many day-to-day activities. Older adults have the opportunity to opt-in to live in an older adult community (OAC) based on their needs and capabilities. This study comprehensively reviews existing governing development regulations and design criteria related to the older adults’ communities, conducts surveys among people involved with some of these communities in California, and recommends improvements to community design for active living and tiered living communities. This study proposes a new scoring system …

Optimization Of Station-Skip In A Cyclic Express Subway Service, Jingfeng Yang, Hai Wang, Jiangang Jin

Research Collection School Of Computing and Information Systems

With rapid population growth and increasing demand for urban mobility, metropolitan areas such as Singapore, Tokyo, and Shanghai are increasingly dependent on public transport systems. Various strategies are proposed to improve the service quality and capacity of bus and subway systems. Express trains—i.e., trains that skip certain stations—are commonly used because they can travel at higher speeds, potentially reduce travel time, and serve more passengers. In this paper, we study cyclic express subway service (CESS), in which express trains provide routine transport service with cyclic (periodic) station-skip patterns that can be used in daily service. We propose an exact Mixed …

Confessions Of A Traffic Engineer: How The Mutcd Impacts Everything, Peter Koonce

PSU Transportation Seminars

Pete Buttigieg, USDOT Secretary of Transportation has described the Manual on Uniform Traffic Control Devices (MUTCD) as “notorious”… and for cities, it has been a challenging document to navigate to implement multimodal solutions. This presentation will share upcoming changes to the Manual, ideas for research to inform practice, and ways that cities can interpret data to make positive change in their community.