Skip to content
News

Research Theme: Infrastructure & Transportation

Includes both management/policy and design/building aspects

Road User Fees in the USA: Theory, Research, and Practice

Chen, P., Shen, Q., & Boardman, S. (2025). Road User Fees in the USA: Theory, Research, and Practice. Journal of Planning Literature. https://doi.org/10.1177/08854122251385953

View Publication

Abstract

This paper examines the theory, research, and practice of road user charge (RUC) in the USA. It explores neoclassical, behavioral, and institutional economic perspectives to assess RUC's environmental benefits, data privacy, public acceptance, and equity implications. A synthesis of recent studies highlights RUC's financial, environmental, social, and urban transportation system impacts. The examination of state and regional initiatives presents several critical challenges associated with the implementation of RUC systems. This study provides a nuanced understanding of RUC's potential and barriers as a sustainable transportation funding mechanism and offers insights into future research and policy development.

An outlook on ride-sourcing price changes: Implications for future transit agency-TNC partnerships

Ashour, L., & Shen, Q. (2025). An outlook on ride-sourcing price changes: Implications for future transit agency-TNC partnerships. Transport Policy, 173, Article 103790. https://doi.org/10.1016/j.tranpol.2025.103790

View Publication

Abstract

Ride-sourcing trip prices charged by transportation network companies (TNCs) have increased significantly compared to before the pandemic, causing concerns about the effectiveness of existing and planned transit agency-TNC partnerships. This paper explores three scenarios of future TNC price changes: (1) price trend extension using forecasting models, (2) price increase in response to local policy changes, and (3) TNC/taxi price convergence due to increased competition. We then investigate the impact of TNC price change on the prospect of transit agency-TNC partnerships, using a case study in the Seattle region. For the first scenario, we employ two time-series models, namely ARIMA and PROPHET, to forecast price changes within the next three years (Oct 2022–Oct 2025) using publicly available Chicago TNC trip data. The results show that TNC's daily average price would reach $3.23 per mile, increasing by 40 % from 2019 average rates. For the second scenario, we track significant policies that directly impacted TNC prices in Seattle and incorporate reported price increases. The resulting estimations indicate that TNC prices would increase by an extra 25 % in response to changes in the minimum wage law. For the third scenario, we use publicly available taxi trip data of the city of Chicago and forecast future taxi prices by estimating time-series models comparable to those for TNC prices. The analysis suggests that due to increased competition, TNC and taxi prices are converging and that the average TNC fare per mile could add another 50 % to the forecasted price if TNC and taxi prices become similar in the upcoming three years. These price changes are shown to have a considerable negative impact on the expected cost-effectiveness of transit agency-TNC partnerships. Although such partnerships could still provide many benefits, transportation planners and policymakers should carefully examine the implications of TNC price increases resulting from changing market and policy environments.

Incorporating equity into the cost-effectiveness evaluation of new mobility: A comparative analysis

Ashour, L., & Shen, Q. (2025). Incorporating equity into the cost-effectiveness evaluation of new mobility: A comparative analysis. Transportation Research. Part D, Transport and Environment, 147, Article 104959. https://doi.org/10.1016/j.trd.2025.104959

View Publication

Abstract

Public transportation in suburban areas faces challenges in providing efficient mobility. Transit Incorporating Mobility on Demand (TIMOD) services have emerged as a potential solution, yet equity considerations remain underexplored. This study incorporates equity into the cost-effectiveness evaluation of TIMOD services, analyzing two suburban areas in the Seattle metropolitan region where a TIMOD service is implemented. Using distributional cost-effectiveness analysis (DCEA), we assess the comparative costs of TIMOD, fixed-route transit, and drive-alone across different income groups and built environments. The study shows that although TIMOD services offer equity benefits for lower-income travelers, they are more equitable in high-density, low-income suburbs. In contrast, their cost-effectiveness is more limited in affluent, low-density areas. These insights highlight the importance of context-specific planning for TIMOD interventions and employ tools such as DCEA for transit agencies to prioritize the deployment of such services in areas where they can maximize social welfare and reduce transportation inequities.

Incorporating mobility-on-demand into public transit in suburban areas: A comparative cost-effectiveness evaluation

Cai, M., Ashour, L. A., Shen, Q., & Chen, C. (2025). Incorporating mobility-on-demand into public transit in suburban areas: A comparative cost-effectiveness evaluation. Transportation Research. Part D, Transport and Environment, 144, Article 104775. https://doi.org/10.1016/j.trd.2025.104775

View Publication

Abstract

Transit Incorporating Mobility-on-Demand (TIMOD) represents the public–private partnerships in which transit agencies incorporate MOD services to supplement fixed-route transit. This study evaluates the cost-effectiveness of TIMOD compared to buses, driving, and ride-hailing in suburban settings. For each alternative, it estimates the marginal costs for travelers, service providers, and transportation externalities, which constitute the marginal social cost. In the study cases, TIMOD is the least cost-effective option, with marginal social cost approximately 20% higher than TNCs and over three times higher than driving. For travelers, TIMOD costs more than driving but less than buses and ride-hailing when considering time value and fare. The cost of TIMOD declines as population density increases. Suburbs with less bus services and higher income residents benefit more from TIMOD, realizing greater reductions in time costs compared to buses. Transit agencies should explore alternative ways to improve mobility for disadvantaged suburban residents by offsetting driving costs and subsidizing TNCs fares.

Keywords

Transit Incorporating Mobility-On-Demand (TIMOD); Public transit; Transportation simulation; Suburban areas; Marginal social cost of travel

Disparities in resilience and recovery of ridesourcing usage during COVID-19

Wang, S., Huang, X., & Shen, Q. (2024). Disparities in resilience and recovery of ridesourcing usage during COVID-19. Journal of Transport Geography, 114, Article 103745. https://doi.org/10.1016/j.jtrangeo.2023.103745

View Publication

Abstract

The COVID-19 pandemic has impacted ridesourcing services dramatically, but empirical research on disparities in the resilience and recovery of ridesourcing has been scarce. To address this literature gap, we used ridesourcing trip data in Chicago to create two time series: one for Census tract-level ridesourcing usage (including pickups and dropoffs) and the other for linkages between origin and destination (OD) pairs. We performed time-series clustering analyses that integrated manifold learning and Gaussian Mixture Modeling to optimize the number of clusters for high-dimensional time-series data. The tract-level usage can be grouped into three clusters, and the OD-pair linkages can be grouped into six clusters. We examined the spatial patterns of the tract-level usage clusters and the OD-pair linkage clusters. Furthermore, we estimated a multinomial logit regression model to examine the relationships between clusters and land use, built environment, and sociodemographic factors. Our results suggested that the share of residential land use had a positive association with high resilience and fast recovery of ridesourcing usage. Limited transportation accessibility and a lack of alternative transportation modes were also associated with high resilience and fast recovery of ridesourcing usage. Trips that linked dense employment centers were less likely to be made during the pandemic. Census tracts with a greater share of minorities or a higher poverty rate tended to generate more ridesourcing trips during the pandemic.

Professor Lee and team begin Port of Seattle funded project “Taxi and Transportation Network Company (TTNC) Electrification Policy Guidance”

Professor Chris Lee and team are beginning a project entitled “Taxi and Transportation Network Company (TTNC) Electrification Policy Guidance,” funded by the Port of Seattle. This project aims to support the Port of Seattle—including Seattle-Tacoma International Airport and the Maritime Division—in developing strategies to reduce carbon emissions from passenger ground transportation. Drawing on outreach to taxi and transportation network company (TNC) drivers (e.g., Uber, Lyft), the project will identify key barriers and opportunities for electrifying commercial ground transportation serving key…

Advancing Active Transportation Through Mobility Justice and Centering Community

Baquero, B. I., Berney, R., Romano, E. F. T., Hicks, O., Getch, R., Hall, C., Mooney, S. J., Rosenberg, D., Shannon, K. L., Saelens, B. E., & Hoerster, K. D. (2024). Advancing Active Transportation Through Mobility Justice and Centering Community. Health Equity, 8(1), 72–730. https://doi.org/10.1089/heq.2024.0087

View Publication

Abstract

Objectives: We established a community–academic–policy partnership to examine mobility challenges and opportunities by centering members of a diverse South Seattle neighborhood.
Methods: Three participatory research methods were used: (a) 30- to 60-min qualitative interviews with community leaders (n = 12) and members (n = 16); (b) a photovoice with youth (n = 10); and (c) mobility audits. We also engaged extensively in community dissemination and advocacy.
Results: Four major themes emerged: experiences with the built environment; conflicting views on promoting active transportation; experiences of danger, violence, and racism while moving in the community; and pride and connections within the community. Mobility audit findings reinforced many community member messages about needed infrastructure changes. Participants consistently expressed the need for neighborhood and city-wide structural improvements to support transportation and mobility, including enhanced public transportation; better lighting, crosswalks, sidewalks, pavement, and curb cuts; and maintenance of a neighborhood mixed-use trail. Participants shared the importance of community connection while walking, rolling, or using public transit and wanted to maintain this experience.
Conclusions: Collectively, findings identified ways to increase nonmotorized transportation and public transit access, safety, and resilience, centering solutions on communities of color. We disseminated and amplified community recommendations to advance mobility justice in South Seattle via a community forum, developing a website, holding meetings with local leaders, and writing through print and electronic media. A key, novel strength of our project was the addition of community organizations, community–academic partners, and government leaders from the project’s inception. Local leaders should engage in mobility justice-focused community engagement to advance equity.

Pacific Coast Architecture Database (PCAD)

PCAD archives a range of information on the buildings and architects of California, Oregon and Washington. Also included are professionals in other fields who have made an impact on the built environment, such as landscape architects, interior designers, engineers, urban planners, developers, and building contractors. Building records are tied to those of their creators (when known) and include historical and geographical information and images. Bibliographical information, such as magazine and book citations and web sites, has also been linked for creators and their partnerships and structures.

View Resource

Awareness, adoption readiness and challenges of railway 4.0 technologies in a developing economy

Awodele, I. A., Mewomo, M. C., Municio, A. M. G., Chan, A. P. C., Darko, A., Taiwo, R., Olatunde, N. A., Eze, E. C., & Awodele, O. A. (2024). Awareness, adoption readiness and challenges of railway 4.0 technologies in a developing economy. Heliyon, 10(4), e25934–e25934. https://doi.org/10.1016/j.heliyon.2024.e25934

View Publication

Abstract

The railway industry has witnessed increasing adoption of digital technologies, known as Railway 4.0, that is revolutionizing operations, infrastructure, and transportation systems. However, developing countries face challenges in keeping pace with these technological advancements. With limited research on Railway 4.0 adoption in developing countries, this study was motivated to investigate the awareness, readiness, and challenges faced by railway professionals towards implementing Railway 4.0 technologies. The aim was to assess the level of awareness and preparedness and identify the key challenges influencing Railway 4.0 adoption in Nigeria's railway construction industry. A questionnaire survey (was distributed to professionals in the railway construction sector to gather their perspectives on awareness of, preparation for, and challenges associated with the use of Railway 4.0 technologies. The results revealed that awareness of Railway 4.0 technologies was moderate, while readiness was low among the professionals. Using exploratory factor analysis, 10 underlying challenge constructs were identified including lack of technical know-how, resistance to change, infrastructure limitations, and uncertainty about benefits, amongst others. Partial Least Square Structural Equation Modelling (PLS-SEM) confirmed these constructs, with reliability and availability, lack of technical know-how, lack of training and resources, and uncertainties in benefit and gains having significant influence on awareness and readiness. The study concludes that focused efforts in training, infrastructure improvement, supportive policies, and communicating the advantages of Railway 4.0 are critical to drive adoption in Nigeria and other developing economies. The findings provide insights into tailoring Railway 4.0 implementation strategies for developing contexts.

Keywords

Railway 4.0; Awareness; Readiness; Challenges; Technologies