; (3) power electronics; (4) vehicle, component, and subsystem manufacturing technologies and processes; (5) engine efficiency and combustion optimization; (6) waste heat recovery; (7) transmission and drivetrains; (8) hydrogen vehicle technologies, including fuel cells and internal combustion engines, and hydrogen infrastructure, including hydrogen energy storage to enable renewables and provide hydrogen for fuel and power; (9) natural gas vehicle technologies; (10) aerodynamics, rolling resistance (including tires and wheel assemblies), and accessory power loads of vehicles and associated equipment; (11) vehicle weight reduction, including lightweighting materials and the development of manufacturing processes to fabricate, assemble, and use dissimilar materials; (12) friction and wear reduction; (13) engine and component durability; (14) innovative propulsion systems; (15) advanced boosting systems; (16) hydraulic hybrid technologies; (17) engine compatibility with and optimization for a variety of transportation fuels including natural gas and other liquid and gaseous fuels; (18) predictive engineering, modeling, and simulation of vehicle and transportation systems; (19) refueling and charging infrastructure for alternative fueled and electric or plug-in electric hybrid vehicles, including the unique challenges facing rural areas; (20) gaseous fuels storage systems and system integration and optimization; (21) sensing, communications, and actuation technologies for vehicle, electrical grid, and infrastructure; (22) efficient use, substitution, and recycling of potentially critical materials in vehicles, including rare earth elements and precious metals, at risk of supply disruption; (23) aftertreatment technologies; (24) thermal management of battery systems; (25) retrofitting advanced vehicle technologies to existing vehicles; (26) development of common standards, specifications, and architectures for both transportation and stationary battery applications; (27) advanced internal combustion engines