2015PDFTech ReportOSTR-2015-01DTFH61-14-V-00025;DTFH61-15-A-00001Technological innovationsTransportation modesGround transportationResearch projectsState of the practiceWorkshopsFutureUnited StatesUnited States. Federal Highway Administration. Office of Corporate Research, Technology, and InnovationMachek, ElizabethLewis, KristinPeirce, SeanBerthaume, AndrewColton, PaigeMorton, TomJohn A. Volpe National Transportation Systems CenterWoodward Communications, Inc.United States. Federal Highway Administration. Exploratory Advanced Research ProgramVolpe National Transportation Systems Center, Technical Reference Center;Federal Highway AdministrationThis report summarizes an initial stage investigation into current research and development of alt...