TSRC

The Dynamics of the California Electric Grid Mix and Electric Vehicle Emission Factors

Zhang, Xingrui
Martin, Elliot
Shaheen, Susan
2025

Electric vehicle (EV) emissions occur when a vehicle is charged and are based on the mix of power sources used during that period. The rapid growth of solar and wind energy has introduced a high degree of variability in the emissions of the grid for both diurnal and annual periodicities. Growth in solar energy has been particularly prominent in California. Using grid mix data spanning April 2018 to April 2023 from the California Independent System Operator (CAISO) and power source emission factors, we evaluate the grid mix at 5 min intervals and estimate the emission factors based on the...

Is electric vehicle carsharing for everyone? from activity patterns to user retention

Yassine, Ziad
Martin, Elliot
Shaheen, Susan
2025

This research explores the user dynamics of electric vehicle (EV) carsharing within underserved communities, focusing on BlueLA, a one-way station-based EV carsharing service in Los Angeles, California. This study employs a mixed-methods approach to evaluate how activity patterns differ between BlueLA member types and how membership type influences user retention rates. We conduct an exploratory data, clustering, and survival analyses, using BlueLA trip activity data, supplemented by insights from a user survey and a general population survey. Our results reveal distinct travel behaviors...

A random intercept latent transition analysis (RI-LTA) of consumer spending across online and in-person channels through the pandemic

Tahlyan, Divyakant
Mahmassani, Hani
Stathopoulos, Amanda
Said, Maher
Walker, Joan
Shaheen, Susan
2025

In this study, we utilize a latent transition analysis with random intercept (RI-LTA) framework to understand the changes to consumer spending landscape through the pandemic across various product categories and acquisition channels. Using data from 785 individuals from across United States at four different time points (pre-COVID, December 2020, March 2021, and March 2022), the presented model revealed five different behavioral classes of consumer spending and the dynamics of movement between classes as a result of the pandemic. The results from the model also revealed that the pandemic’s...

What Makes the Route More Traveled? Optimizing U.S. Suburban Microtransit for Sustainable Mobility

Pan, Alexandra
Shaheen, Susan
2025

Microtransit services that provide pooled on-demand transportation with dynamic routing have been used in low-density areas since the 1970s, but improvements to routing technology have led to a resurgence of interest in the past decade. Questions remain about the effectiveness of microtransit to serve riders in low-density, car-dependent suburban areas. Better understanding of the factors underlying microtransit ridership can improve usage of these services and shift travelers to more sustainable modes in suburban areas. We compile a database of suburban microtransit programs from 32...

In-person, hybrid or remote? Employers’ perspectives on the future of work post-pandemic

Tahlyan, Divyakant
Mahmassani, Hani
Stathopoulos, Amanda
Said, Maher
Shaheen, Susan
Walker, Joan
Johnson, Breton
2024

We present an employer-side perspective on remote work through the pandemic using data from top executives of 129 employers in North America. Our analysis suggests that at least some of the pandemic-accelerated changes to the work location landscape will likely stick; with some form of hybrid work being the norm. However, the patterns will vary by department (HR/legal/sales/IT, etc.) and by sector of operations. Top three concerns among employers include: supervision and mentoring, reduction in innovation, and creativity; and the top three benefits include their ability to retain / recruit...

Communities Are Experimenting with Microtransit to Fill Critical Gaps in Public Transit Service – What Have We Learned so Far?

Shaheen, Susan
Cohen, Adam
Wolfe, Brooke
Martin, Elliot
2024

Microtransit is a technology-enabled transit service that typically employs shuttles or vans (Figure 1) to provide on-demand transportation with dynamic routing. While many rides are dispatched and paid via a smartphone, many services also provide a telephone booking option. A few services accept cash payment and street hails (similar to taxis). Variations of microtransit can include fixed schedules and routes and larger or smaller vehicles. Typically, microtransit services are operated by or provided on behalfof a government entity or nonprofit organization, although privately operated...

Environmental Impacts of Transportation Network Company (TNC)/Ride-Hailing Services: Evaluating Net Vehicle Miles Traveled and Greenhouse Gas Emission Impacts within San Francisco, Los Angeles, and Washington, D.C. Using Survey and Activity Data

Martin, Elliot
Shaheen, Susan
Wolfe, Brooke
2024

Transportation Network Companies (TNCs) play a prominent role in mobility within cities across the globe. However, their activity has impacts on vehicle miles traveled (VMT) and greenhouse gas (GHG) emissions. This study quantifies the change in personal vehicle ownership and total miles driven by TNC drivers in three metropolitan areas: San Francisco, CA; Los Angeles, CA; and Washington, D.C. The data sources for this analysis comprise two surveys, one for TNC passengers (N = 8630) and one for TNC drivers (N = 5034), in addition to data provided by the TNC operators Uber and Lyft. The...

From Taxis to Ridehailing: Examining Gender Issues for Female Drivers and Passengers

Shaheen, Susan
Cohen, Adam
Wolfe, Brooke
Champlin, Jacob
2024

This report analyzes gender issues for female drivers and passengers of transportation network companies (TNCs) and taxis. Between August 2023 and May 2024, the researchers conducted driver and rider focus groups (n=8 drivers and n=8 passengers); a driver survey (n=170); a TNC user/non-user survey (n=440, including n=217/440 taxi non-users, n=7/440 TNC non-users, and a subset of n=5/440 non- users of TNCs and taxis); and expert interviews (n=13). This research finds that both female drivers and passengers experience an array of safety concerns and challenges traveling with young children...

Challenges and Opportunities Facing App-Based Gig Drivers Extend Beyond Driver Pay

Shaheen, Susan
Wolfe, Brooke
Cohen, Adam
Broader, Jacquelyn
2024

Throughout the U.S., app-based gig drivers provide valuable services for courier network services (CNS) like Instacart, Uber Eats and DoorDash, and transportation network companies (TNCs) such as Uber and Lyft. In California, gig labor classification is governed among other things by Assembly Bill 5 (AB 5), which passed in 2019, and Proposition 22 (Prop 22) adopted in 2020. AB 5 established the ABC Test for worker classification in California labor law. The ABC Test results in most app-based drivers being classified as employees, who are due full labor rights and benefits in California....

Planning for Advanced Air Mobility

Cohen, Adam
Shaheen, Susan
Wulff, Yolanka
2024

Advanced air mobility (AAM) could result in fundamental changes to land use and the built environment and transform how people access essential services (e.g., emergency and medical services), goods, and mobility. While the impacts of these innovations remain to be seen, planners and policymakers need to prepare for these changes to minimize the potential for adverse impacts and maximize the likelihood of sustainable and equitable outcomes.