The National Academies

NCHRP 20-102(23) [Anticipated]

Potential Impacts of Highly Automated Vehicles and Shared Mobility on Traveler Behavior
[ NCHRP 20-102 (Impacts of Connected Vehicles and Automated Vehicles on State and Local Transportation Agencies--Task-Order Support) ]

  Project Data
Funds: $450,000
Staff Responsibility: Stephan A. Parker
Comments: In development
Fiscal Year: 2019



In recent years, economic, environmental, and social forces have quickly given rise to shared and on-demand mobility, a collective of entrepreneurs and consumers leveraging technology to share transportation resources, save money, and generate capital. Ridesourcing/ transportation network company (TNC) services, such as Lyft and Uber, and peer-to-peer carsharing services, such as Getaround and Turo, have become part of a sociodemographic trend that has pushed shared on-demand mobility from the fringe into the mainstream. A number of social, environmental, and behavioral impacts have been attributed to shared mobility, and an increasing body of empirical evidence supports many of these relationships. The various effects can be grouped into four categories: (1) travel behavior, (2) environmental, (3) land use, and (4) social. These impacts can include sold vehicles or delayed or foregone vehicle purchases; increased use of some alternative transportation modes (e.g., walking, biking); changes in vehicle miles/kilometers traveled (VMT/VKT); increased access and mobility; reduced fuel consumption and greenhouse gas emissions (particularly when fleets are electrified); and greater environmental awareness. However, the impacts of automated vehicles (AVs) and shared AVs (SAVs) are uncertain. One possible outcome is that existing roadway capacity may increase due to more efficient operations associated with automation (e.g., closer vehicle spacing, etc.). Conversely, there is a possibility for widespread AV and SAV adoption that could induce VMT by making automobile trips more convenient and affordable with fewer hassles than personal driving, such as parking. This could potentially negatively impact the nation’s roadway infrastructure through increased VMT and vehicle use. As such, more research is needed to understand the impacts of highly AVs (HAVs) and SAVs on travel behavior.




The objective of this research is to explore the potential impacts of HAVs and shared mobility on VMT and system capacity, as well as the behavior of other road users, particularly in light of the potential for zero occupancy vehicles.


Key objectives of this research include:

·         Understanding the impact of HAVs and SAVs on private vehicle ownership and use in an automated future;

·         Understanding the relationship and interaction of HAVs and SAVs on public transportation;

·         Understanding the impacts of HAVs and SAVs on individual modal choice and willingness to use active transportation, public transportation, and other modes; and

·         Understanding the VMT, congestion, air emissions (greenhouse gas (GHG) emissions and criteria pollutants) of SAVs and HAVs under a variety potential deployment scenarios, such as:

o    The travel behavior and environmental impacts of HAVs and SAVs on jobs and housing location decisions (i.e., will HAVs/SAVs encourage denser urban cores, suburban/exurban growth, or a combination of both, and under what circumstances?);

o    The travel behavior and environmental impacts of HAVs and SAVs based on business model deployment (i.e., business-to-consumer, peer-to-peer, or mixed fleets); and

o    The travel behavior and environmental impacts of HAVs and SAVs based on a variety of pricing and pooling scenarios (i.e., will zero occupant vehicles be permissible and, if so, under what circumstances?).



Outputs from this research will inform policymakers at all level of government on the potential travel behavior impacts of HAVs and SAVs. The results will help to inform proactive policy development to encourage positive HAV/SAV adoption outcomes, such as reduced congestion and air emissions (GHGs and criteria pollutants). Additionally, the results of this research will enhance understanding of the potential societal adoption and barriers associated with SAV use and the willingness to sell or forego the purchase of a personal AV. Finally, this research will help the public sector understand the potential impacts of HAVs and SAVs on mode choice and the willingness of users to use active and public transportation in an automated future.




The study should build upon NCHRP 20-102(09) and synthesis efforts on international pilot deployments. It should also include other disruptive modal choices like e-scooters. This is a priority issue for the TRB Forum on Automated Vehicles and Shared Mobility. This project will be combined with TCRP Project B-47, Mobility Inclusion for Un(der)served Population with the Emerging Technologies ($250,000).

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