This grant supports a multidisciplinary research effort led by the Institute for Transportation Studies at the University of California, Davis (ITS-Davis) to examine natural gas as an alternative fuel option to power trucks, other long-haul vehicles, municipal bus and taxi fleets, and light-duty passenger vehicles. Bringing together leading economists, engineers, geographers, policy experts, and computer scientists, ITS-Davis will organize a workshop on the issue and commission a series of papers providing a comprehensive overview of the tradeoffs associated with the use of natural gas as an alternative fuel in the transportation sector. Data from the workshop will then be used to enrich ITS-Davis’s model of the infrastructure and refueling network that must sustain any transition to natural gas as an alternative fuel. Working closely with researchers at Arizona State University, ITS-Davis also plans to expand its model to accommodate changes in diesel and natural gas fuel prices, alternative technology costs, various rates of new vehicle diffusion, altered traffic flow patterns, and changes to state-level policies.