This primer synthesizes existing literature on the definitions and types of shared mobility services available; reviews North American shared mobility impact studies; discusses the government’s role; reviews success stories; examines challenges, lessons learned, and proposed solutions; and concludes with guiding principles for public agencies. The study aims to provide an overview of this emerging field and outline current understandings as shared mobility continues to evolve and develop in the years to come. Shared mobility services reviewed in this study include bike sharing, car sharing, carpooling, on-demand car sharing, scooter sharing, van pooling, car rental, casual carpooling, Courier Network Services (CNS) (also referred to as flexible goods delivery), limousines, taxis, pedicabs, public transportation, and shuttles.
An increasing body of empirical evidence indicates that shared modes can provide numerous transportation, land use, environmental, and social benefits. While impact studies on roundtrip carsharing and public bikesharing are fairly extensive, the impacts of newer service models and emerging modes, such as one-way carsharing, peer-to-peer models, scooter sharing, on-demand ride services (such as ridesharing and ridesourcing), and CNS are less studied and understood. The primer study explores the current understanding of the impacts associated with several shared modes, specifically membership-based carsharing, bikesharing, and ride sourcing service options. Eighteen North American roundtrip carsharing studies that include both third-party and operator-led stated-preference survey data evaluations were cited in this primer. For bikesharing, fourteen user survey-based studies focusing on service catchment areas in U.S. as well as several international locations were cited. As for evaluation of ridesourcing impacts, a single study focusing on two transportation network company (TNC) service options was cited.
Review of eighteen studies evaluating the impacts of carsharing companies with a catchment area located in North America revealed the following benefits:
- Reduced vehicle ownership due to either sales or deferred purchases. Between 2.5 and 33 percent of carsharing service users sold their personal vehicles, and between 25 and 71 percent of members avoided an auto purchase because of carsharing.
- The average reduction in the carsharing member’s vehicle miles traveled was within 7.9 to 79.8 percent range.
- Savings to carsharing members were within an estimated range of $154 to $435 annually for U.S. members and $392 to $492 CAD for Canadian members.
- Between 12 to 54 percent of the carsharing members indicated that they walk more.
Review of fourteen studies evaluating the impacts of bikesharing companies located in U.S, Canada, Europe, and China revealed the following benefits:
- Annual CO2 emission reductions were in a range of 36.56 metric tons (reported by a Colorado bikesharing company) to 69,715 metric tons (reported by a bikesharing company in China).
- Evaluations indicate a modal shift away from driving (drive less frequently due to bikesharing). The reduction was in a range of 19 percent to 52.4 percent.
- Reduction in vehicle ownership was in a range of 1.9 percent to 3.6 percent.
A recent study of ridesourcing in the San Francisco Bay area found that:
- Ridesourcing wait times tended to be substantially shorter than taxi hail and dispatch wait times. 39 percent and 6 percent of survey respondents in the Bay Area stated they would have taken a taxi or drive alone in a personal car, respectively, if TNC service options were unavailable