Abstract: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.