Since the late 1990s, more than 25 U.S. shared-use vehicle programs—including carsharing and station cars—have been launched. Given the presumed social and environmental benefits, the majority of these programs received some governmental support, primarily in the form of start-up grants and subsidized parking. As of July 2003, 15 shared-use vehicle programs were in existence, including 11 carsharing organizations, 2 carsharing research pilots, and 2 station car programs. Over the past 5 years, membership in U.S. carsharing programs has experienced exponential growth. Despite this expansion, the social and environmental impacts and long-term sustainability of these services remain unclear. As part of a U.S. shared-use vehicle survey (August 2002 to July 2003), market growth and trends as well as limited, systematic evaluation of program impacts were documented. Although 80% of shared-use programs implement internal customer surveys (initially or as follow-up), few independent studies have been conducted to date. Across organizations, participant use and program benefits are measured with various study tools and metrics. Given current shared-use vehicle growth and the ongoing interest of policymakers and governmental agencies in this concept, a longitudinal monitoring approach to better understand market developments, social and environmental impacts, and targeted policy strategies is recommended. Furthermore, it is concluded that coordinated, programwide data collection (consistent survey instruments and performance measures) could enhance overall market awareness and the credibility of shared-use vehicle organizations in leveraging additional public support.

Shared-use vehicle services provide members with access to a vehicle fleet for use as needed, without the hassles and costs of individual automobile ownership. From June 2001 to July 2002, there was a survey of 18 U.S. shared-use vehicle organizations on a range of topics, including organizational size, partnerships, pricing, costs, and technology. Although survey findings demonstrate a decline in the number of organizational starts in the last year, operational launches into new cities, membership, and fleet size continue to increase. Several growth-oriented organizations are responsible for most of this expansion. Several factors were explored that challenge shared-use vehicle growth, such as high capital investment (or start-up costs), dramatic insurance rate hikes, and scarcity of cost-effective technologies. Although the findings of early niche markets are encouraging, the ability of this emerging sector to actualize its total environmental, economic, and social goals may be limited without the collective support of private industry (e.g., automobile manufacturers, insurance providers, technology producers); public agents (e.g., transit and governmental agencies); and shared-use vehicle programs. Indeed, public–private partnerships and cooperation among shared-use vehicle providers may play a key role in addressing insurance and technology costs and ensuring the long-term viability of this market.