Environment

Behavioral and Sociodemographic Impacts of Carsharing

Shaheen, Susan A.
Pan, Alexandra
2024

The growth of carsharing in North America since the service was first introduced in 1994 has had notable impacts on travel behaviour, including vehicle ownership and modal shift. Existing forms of carsharing (e.g., roundtrip, one-way, and peer-to-peer) alter the conventional cost structure of driving from one of fixed cost to variable cost. Multiple studies have shown that overall, carsharing users increase public transit and non-motorized modal use, with some users also selling their vehicle or postponing future vehicle purchases as a result of being a carsharing member. These modal...

Advancing Social Equity and Congestion Relief: Understanding the Travel Needs of Underserved Populations That Rely on Transportation Network Companies in the San Francisco Bay Area

Shaheen, Susan
Gosselin, Kate
Broader, Jacquelyn
Cohen, Adam
2022

Transportation Network Companies (TNCs) enable travelers to order and pay for rides on-demand using an online application that connects them with drivers using their personal vehicles. While these modes present opportunities to increase individual mobility and access, they also can worsen congestion and increase vehicle emissions. Researchers explored factors impacting the willingness to use pooled TNCs and identified strategies/policies that could be employed to reduce congestion from TNC use. Researchers conducted a literature review, interviews with TNC experts, semi-structured...

Do Incentives Make a Difference? Understanding Smart Charging Program Adoption for Electric Vehicles

Wong, Steven D.
Shaheen, Susan A.
Martin, Elliot PhD
Uyeki, Robert
2023

Climate change and environmental problems have spurred new strategies to reduce fossil fuel consumption in transportation. Two important strategies include a rapid transition to green energy and the replacement of internal combustion vehicles with electric vehicles (EVs). However, the increasing demand for electricity by EVs, especially from time-dependent green sources of energy (e.g., solar, wind), will likely overload the grid at peak hours. Rather than build costly infrastructure improvements for distribution and generation, smart charging programs for EVs could defer charging to off-...

Zero-emission vehicle exposure within U.S. carsharing fleets and impacts on sentiment toward electric-drive vehicles

Shaheen, Susan
Martin, Elliot
Totte, Hannah
2020

Reducing carbon emissions from the United States (U.S.) transportation sector has emerged as a priority action to combat climate change. Carsharing and zero-emission vehicles (ZEVs) could be integral to creating a more sustainable transportation system. This paper presents the results of a study that evaluated the impacts of ZEV exposure on U.S. carsharing users. Surveys were administered to control and experimental groups of carsharing members that used shared PHEVs or EVs. Results showed that users who drove shared PHEVs or EVs more frequently were more likely to exhibit improved ZEV...

Ridesharing in North America: Past, Present, and Future

Chan, Nelson D.
Shaheen, Susan A.
2011

Since the late-1990s, numerous ridematching programs have integrated the Internet, mobile phones, and social networking into their services. Online ridematching systems are employing a range of new strategies to create “critical mass:” 1) regional and large employer partnerships, 2) financial incentives, 3) social networking to younger populations, and 4) real-time ridematching services that employ “smartphones” and automated ridematching software. Enhanced casual carpooling approaches, which focus on “meeting places,” are also being explored. Today, ridesharing represents approximately 8...

California's Zero-Emission Vehicle Mandate: Linking Clean-Fuel Cars, Carsharing, and Station Car Strategies

Shaheen, Susan
Wright, John
Sperling, Daniel
2002

To reduce transportation emissions and energy consumption, policymakers typically employ one of two approaches—changing technology or changing behavior. These strategies include demand management tools, such as ridesharing and vehicle control technologies—cleaner fuels and fuel economy. Despite the benefits of a combined policy approach, these strategies are normally employed separately. Nevertheless, they have been linked occasionally, for instance in theelectric station car programs of the 1990s. Station cars are vehicles used by transit riders at the start or end of a trip.In 1990, the...

Greenhouse Gas Emission Impacts of Carsharing in North America

Martin, Elliot
Shaheen, Susan A.
2011

This paper evaluates the greenhouse gas (GHG) emission impacts that result from individuals participating in carsharing organizations within North America. The authors conducted an online survey with members of major carsharing organizations and evaluated the change in annual household emissions (e.g., impact) of respondents that joined carsharing. The results show that a majority of households joining carsharing are increasing their emissions by gaining access to automobiles. However, individually, these increases are small. In contrast, the remaining households are decreasing their...

Travel Effects of a Suburban Commuter Carsharing Service: CarLink Case Study

Shaheen, Susan A.
Rodier, Caroline J.
2005

Since 1998, carsharing programs (or short-term auto rentals) in the U.S. have experienced exponential membership growth. As of July 2003, 15 carsharing organizations collectively claimed 25,727 members and 784 vehicles. Given this growing demand, decision makers and transit operators are increasingly interested in understanding the potential for carsharing services to increase transit use, reduce auto ownership, and lower vehicle miles traveled. However, to date, there is only limited evidence of potential program effects in the U.S. and Europe. This paper presents the travel effects of...

Power Trips: Early Understanding of Preparedness and Travel Behavior During California Public Safety Power Shutoff Events

Wong, Steven D.
Broader, Jacquelyn C.
Shaheen, Susan A.
2022

Recent wildfire risks in California have prompted the implementation of public safety power shutoff (PSPS) events, procedures enacted by utility operators to de-energize parts of the electrical grid and reduce the likelihood of wildfire ignition. Despite their yearly occurrence, PSPS events are severely understudied, and little is known about how these events impact disaster preparation activity, travel behavior, and transportation systems. With growing wildfire risks in North America and beyond, PSPS events require immediate and thorough research to reduce their negative externalities and...

Mobility and Energy Impacts of Shared Automated Vehicles: A Review of Recent Literature

Shaheen, Susan
Bouzaghrane, Mahamed Amine
2019

The purpose of this review is to present findings from recent research on Shared automated vehicles (SAV) impacts on mobility and energy. While the literature on potential SAV impacts on travel behavior and the environment is still developing, researchers have suggested that SAVs could reduce transportation costs and incur minimal increases in total trip time due to efficient routing to support pooling. Researchers also speculate that SAVs would result in a 55% reduction in energy use and ~ 90% reduction in greenhouse gas (GHG) emissions.SAV impacts on mobility and energy are uncertain....