Policy

Understanding Curb Management and Targeted Incentive Policies to Increase Transportation Network Company Pooling and Public Transit Linkages

Susan Shaheen
Darling, Wesley
Broader, Jacquelyn
Cohen, Adam
2021

Transportation network company (TNCs) rides that are shared amongst users (i.e., pooled) can offer a variety of benefits including increased mobility and reduced transportation emissions. However, very few TNC users select pooled trips and not all pooled rides are matched with other riders. This report supports increased pooling by exploring different pooling strategies and incentives. TNC users were actively engaged to offer insights through the photovoice methodology (a participatory research method that allows community members to use photography to communicate their personal...

Shared Mobility Services: Prioritizing Social Good

Susan Shaheen
Adam Cohen
2024

Access to transportation is integral to enhancing opportunities for employment, education, health care, and recreation. SAVs will not fundamentally solve today's transportation challenges. To solve them, AVs require thoughtful planning and public policies that balance societal goals with commercial interests. To harness and maximize the social and environmental benefits of highly automated vehicles, we need to prepare for a multiphase transition toward highly automated vehicles today. If driver-less vehicles are thoughtfully implemented with access and social/racial equity in mind,...

Shared Mobility Policies for California

Susan Shaheen
Cohen, Adam
2018

In recent years, economic, environmental, and social forces have quickly given rise to the “sharing economy,” a collective of entrepreneurs and consumers leveraging technology to share resources, save money, and generate capital. Shared mobility—the shared use of a vehicle, bicycle, or other low-speed travel mode—is an innovative transportation strategy that enables users to have short-term access to a transportation mode on an as-needed basis. Business-to-consumer services, such as Zipcar and car2go, and peer-to-peer carsharing and shared ride services, such as Getaround, Turo, Lyft, and...

Policy and Regulatory Environment: Shared Automated Vehicles

Susan Shaheen
Adam Cohen
Stocker, Adam D.
2024

This chapter examines the policy implications of shared automated vehicles (SAVs). It discusses the current state of automated vehicle (AV) and SAV policy in the United States (U.S.) and assesses possible future technology deployment and adoption scenarios. The discussion explores a variety of topics related to SAVs and recommends policy approaches regarding these topics. The authors examine shared mobility policies and developments to compare and contrast possible SAV approaches. The policy topics covered in this chapter include: (1) passenger safety; (2) data sharing; (3) mitigating for...

A Research Roadmap for Transportation and Public Health

Sandt, LS
West, A
Johnson, S
Brookshire, K
Evenson, K
Blackburn, L
Peach, K
Tartala, M
Ricklin, A
Shah, S
Daniel Rodriguez
Coburn, J
2019

States and localities are beginning to recognize and act on the connection between health and transportation. A growing number of entities have produced a number of resources, guidance documents, and strategic plans on the topic.

The TRB National Cooperative Highway Research Program's NCHRP Research Report 932: A Research Roadmap for Transportation and Public Health builds upon this body of work to provide a plan for funding research over the next decade that can lead to greater consideration of health issues in transportation contexts.

Staging at the Curb: Evaluating the Impacts of Shared Automated Vehicle Fleet Operations Under Curb Usage Restrictions

Bahk, Younghun
Hyland, Michael
Susan Shaheen
Wolfe, Brooke
Adam Cohen
2026

Shared automated vehicle (SAV) ridehailing services are now operating in several metropolitan regions in the United States. While providing benefits, SAV services may exacerbate issues related to curb usage and vehicle kilometers traveled (VKT) in urban areas. The objective of this study is to provide guidance to cities by evaluating the impacts of SAVs’ short-term curb usage for staging between serving ride requests, under different curb restrictions and SAV operational strategies. We focus on the following performance metrics: VKT, curb productivity, customer wait time, and customer...

Navigating Uncertainty in Advanced Air Mobility: Scenario Planning for Policy Pathways at San Francisco International Airport

Susan Shaheen
Adam Cohen
Wolfe, Brooke
2026

Advanced Air Mobility (AAM) includes innovative aviation technologies and services that could alter how people and goods are transported. However, future AAM growth and potential regional integration are uncertain and influenced by a range of factors. In this paper, we report findings from expert interviews (n = 35) and a scenario planning workshop (n = 32 stakeholders), conducted between August 2024 and July 2025, to explore potential alternative futures for AAM at the San Francisco International Airport (SFO) and the greater San Francisco Bay Area. We applied a two-axis framework:...

Curb Staging: Understanding the Impacts of Automated Vehicle Ridehail Fleet Operations Under Different Parking Policies

Bahk, Younghun
Hyland, Michael
Susan Shaheen
Wolfe, Brooke
Adam Cohen
2025

Automated vehicle (AV) ridehailing services are now operating in several metropolitan regions in the United States. While providing benefits, AV ridehailing services may exacerbate issues related to curb usage and vehicle kilometers traveled (VKT) in urban areas. The objective of this study is to provide guidance to cities by evaluating the impacts of AVs' short-term curb usage for staging between serving ride requests. We focus on the following performance metrics: VKT, curb productivity, customer wait time, and customer matching rate. To perform the analysis, we use a high-fidelity...

The Impacts of Shared and Automated Mobility

Susan Shaheen
Adam Cohen
2024

This chapter reviews findings from shared mobility studies including ride-sharing (carpooling and vanpooling), carsharing, (bikesharing and scooter sharing), and TNCs. We conclude with a discussion of shared automated vehicles (SAVs) and their potential impacts.

Considerations for Social Distancing on Public Transportation During the COVID-19 Recovery

Adam Cohen
2020

COVID-19 has presented public transit agencies with unprecedented operational and fiscal challenges. In the San Francisco Bay Area, for example, public transit ridership remains approximately 90% below pre-pandemic levels as of November 10, 2020, according to Transit App. It is generally agreed that personal protective measures (i.e., masks, face shields, gloves), sanitation, and air ventilation — combined with social distancing — reduces the spread of COVID-19. However, experts do not agree on the minimum...