| 21CTP | 21st Century Truck Partnership |
| ABS | antilock braking system |
| A/C | air conditioning |
| ACES | Advanced Collaborative Emission Study |
| AEC MOU | Advanced Engine Combustion Memorandum of Understanding |
| AH | ampere-hour |
| AHHPS | advanced heavy hybrid propulsion system |
| ALVW | adjusted loaded vehicle weight |
| ANL | Argonne National Laboratory |
| APBF | advanced petroleum based fuels |
| API | American Petroleum Institute |
| APU | auxiliary power unit |
| ARC | Automotive Research Center |
| ARRA | American Recovery and Reinvestment Act |
| ASTM | American Society for Testing and Materials |
| AT | aftertreatment |
| ATA | American Trucking Association |
| ATRI | American Transportation Research Institute |
| AVTA | Advanced Vehicle Testing Activity |
| BAC | blood alcohol content |
| bbl/day | barrels per day |
| bhp-h | brake horsepower-hour |
| BMEP | brake mean effective pressure |
| BSHR | brake specific heat rejection |
| BTE | brake thermal efficiency |
| BTL | biomass-to-liquids |
| BTU | British thermal unit |
| CAC | compressor after cooler |
| CARB | California Air Resources Board |
| CAT | Caterpillar |
| CDL | commercial driver’s license |
| CERDEC | Communications-Electronics Research, Development and Engineering Center |
| CFD | computational fluid dynamics |
| CH4 | methane |
| CLEERS | Crosscut Lean Exhaust Emission Reduction Simulations |
| CLOSE | Collaborative Lubricating Oil Study on Emissions |
| CMV | commercial motor vehicle |
| CO | carbon monoxide |
| CO2 | carbon dioxide |
| CO2-eq | CO2-equivalent |
| CRADA | Cooperative Research and Development Agreement |
| CRC | Coordinating Research Council |
| CRS | Caterpillar Regeneration System |
| CTEI | Commercial Traffic Effects Institute |
| DCT | Diesel Crosscut Team |
| DDC | Detroit Diesel Corporation |
| DEC | Diesel Emission Control |
| DEER | Directions in Engine-Efficiency and Emissions Research (formerly Diesel Engine-Efficiency and Emissions Research) |
| DEF | Diesel Exhaust Fluid |
| DERA | Diesel Emission Reduction Act |
| DME | dimethyl ether |
| DOC | diesel oxidation catalyst |
| DOD | U.S. Department of Defense |
| DOE | U.S. Department of Energy |
| DOT | U.S. Department of Transportation |
| DPF | diesel particulate filter |
| DPIM | Dual Power Inverter Model |
| ECU | environmental control unit |
| EERE | Energy Efficiency and Renewable Energy (Office of) |
| EGR | exhaust gas recirculation |
| EIA | Energy Information Administration |
| EISA | Energy Independence and Security Act |
| EMA | Engine Manufacturers Association |
| EMD | engine manufacturer diagnostic |
| EPA | U.S. Environmental Protection Agency |
| EPAct 2005 | Energy Policy Act of 2005 |
| EPS | Electrified Parking Spaces |
| ESC | electronic stability control |
| EU | European Union |
| FACE | Fuels for Advanced Combustion Engines |
| FAME | fatty acid methyl esters |
| FCFP | FreedomCAR and Fuel Partnership |
| FCVT | FreedomCAR and Vehicle Technologies (Office of) |
| FHWA | Federal Highway Administration |
| FMCSA | Federal Motor Carrier Safety Administration |
| FMVSS | Federal Motor Vehicle Safety Standards |
| FOA | Funding Opportunity Announcement |
| FOH | fuel-operated heater |
| FOT | field operational test |
| F-T | Fischer-Tropsch |
| FTP | Federal Test Procedure |
| FY | fiscal year |
| GAC | granular activated carbon |
| gal | gallon |
| g/bhp-h | grams per brake horsepower-hour |
| GCW | gross combined weight |
| GES | General Estimates System |
| GFIC | ground-fault interrupter circuit |
| GHG | greenhouse gas |
| g/mi | grams per mile |
| gpm | gallons per mile |
| GPS | global positioning system |
| GREET | Greenhouse Gas Regulated Emissions, and Transportation |
| GTL | gas-to-liquid |
| GVW | gross vehicle weight |
| GVWR | Gross Vehicle Weight Rating |
| HC | hydrocarbon |
| HCCI | homogeneous-charge compression ignition |
| HD | heavy-duty |
| HECC | High Efficiency Clean Combustion |
| HEI | Health Effects Institute |
| HEMTT | Heavy Expanded Mobility Tactical Truck |
| HEV | hybrid electric vehicle |
| HFC | halogenated fluororcarbon |
| HFRR | high frequency reciprocating rig |
| HHDDE | heavy heavy-duty diesel engine |
| HHDDT | Heavy Heavy-Duty Dieset Truck |
| HHV | hybrid heavy-duty electric vehicle |
| HLA | hydraulic lift assist |
| HMMWV | High Mobility Multipurpose Wheeled Vehicle |
| HP | high pressure |
| hp | horsepower |
| HPV | high productivity vehicle (aka LCV) |
| HTHS | high temperature high shear |
| HTML | High Temperature Materials Laboratory |
| HVAC | heating, ventilation, and air conditioning |
| HVD | high-volatility diesel |
| HWFET | highway fuel economy test |
| IC | internal combustion |
| ICE | internal combustion engine |
| IGBT | insulated gate bipolar transistor |
| IRS | Internal Revenue Service |
| ISG | integrated starter-generator |
| ISTEA | Intermodal Surface Transportation Efficiency Act |
| ITS | Intelligent Transportation Systems |
| IVBSS | Integrated Vehicle-Based Safety Systems |
| JCAP | Japanese Clean Air Program |
| JCS | Johnson Controls-SAFT |
| JP-8 | Jet Propellant 8 |
| KOH | potassium hydroxide |
| kWh | kilowatt-hour |
| L | liter |
| LANL | Los Alamos National Laboratory |
| lb | pound |
| LCFS | Low Carbon Fuel Standard |
| LCV | Long Combination Vehicle (aka HPV) |
| LD | light-duty |
| LDT | light-duty truck |
| LDT1 | light-duty truck 1 |
| LDV | light-duty vehicle |
| LDW | lane departure warning |
| LEV | Low Emission Vehicle |
| LHDDE | light heavy-duty diesel engine |
| LI | lithion-ion |
| LLNL | Lawrence Livermore National Laboratory |
| LNT | lean NOx trap |
| LP | low pressure |
| LSD | low sulfur diesel |
| LS/SF | long sleeper tractor and straight frame |
| LTC | low-temperature combustion |
| LVW | loaded vehicle weight |
| µm | micrometer |
| MBRC | Miles Between Road Call |
| MD/HD | medium-duty/heavy-duty |
| MDPV | medium-duty passenger vehicle |
| MDV | medium-duty vehicle |
| MET | More Electric Truck |
| MFC | Model Fund Consortium |
| MHDDE | medium heavy-duty diesel engine |
| MHDV | medium- and heav-duty vehicle |
| mi | mile |
| mpg | miles per gallon |
| mph | miles per hour |
| msec | millisecond |
| MYPP | Multi-Year Program Plan |
| N2O | nitrous oxide |
| NAC | National Automotive Center |
| NAC NOx | Absorber Catalysts |
| NASA | National Aeronautics and Space Administration |
| NCSU | North Caroline State University |
| NEC | National Electric Code |
| NETL | National Energy Technology Laboratory |
| NFAC | National Full-Scale Aerodynamics Complex |
| NHWBS | next-generation wide base single (tires) |
| NHTSA | National Highway Traffic Safety Administration |
| nm | nanometer |
| NMHC | nonmethane hydrocarbon |
| NOx | oxides of nitrogen |
| NPBF | non-petroleum based fuels |
| NPRM | Notice of Proposed Rulemaking |
| NRC | National Research Council |
| NREL | National Renewable Energy Laboratory |
| NTE | Not-to-Exceed |
| NTP | National Toxicology Program |
| NTSB | National Transportation Safety Board |
| OBD | on-board diagnostic |
| OECD | Organization for Economic Co-operation and Development |
| OEM | original equipment manufacturer |
| OHVT | Office of Heavy Vehicles Technology |
| ORNL | Oak Ridge National Laboratory |
| PART | Program Assessment Rating Tool |
| PC | passenger car |
| PCCI | pre-mixed charge compression ignition |
| PEM | polymer electrolyte membrane |
| PHEV | plug-in hybrid electric vehicle |
| PM | particulate matter |
| PM2.5 | particulate matter smaller than 2.5 micrometers in diameter (also PM10) |
| PNGV | Partnership for a New Generation of Vehicles |
| PNNL | Pacific Northwest National Laboratory |
| ppm | parts per million |
| PSAT | Powertrain Systems Analysis Toolkit |
| psi | pounds per square inch |
| PTO | power take-off |
| PZEV | Partial Zero Emission Vehicle |
| R&D | research and development |
| RFS | Renewable Fuels Standards |
| rpm | revolutions per minute |
| SAE | Society of Automotive Engineers |
| SCR | selective catalytic reduction |
| SECA | Solid State Energy Conversion Alliance |
| SET | Supplemental Emission Test |
| SI | spark-ignited |
| SNL | Sandia National Laboratories |
| SNS | Spellation Neutron Source |
| SO2 | sulfur dioxide |
| SOFC | solid oxide fuel cell |
| STEP | Shorepower Truck Electrification Project |
| SULEV | Super Ultra Low Emission Vehicle |
| SUV | sport utility vehicle |
| 21CTP | 21st Century Truck Partnership |
| TACOM | U.S. Army Tank-Automotive Command |
| TARDEC | Tank-Automotive Research, Development and Engineering Center |
| TMA | Truck Manufacturers Association |
| TRB | Transportation Research Board |
| TSE | truck stop electrification |
| UDDS | Urban Dynamic Driving Schedule |
| UFP | ultra-fine particulates |
| ULEV | Ultra Low Emission Vehicle |
| ULSD | ultralow-sulfur diesel |
| USABC | U.S. Advanced Battery Consortium |
| USCAR | U.S. Council for Automotive Research |
| UTQGS | Uniform Tire Quality Grading System |
| V2I | vehicle to infrastructure |
| V2V | vehicle to vehicle |
| VG | variable geometry |
| VIUS | Vehicle Inventory and Use Survey |
| VMT | vehicle miles traveled |
| VSST | Vehicle Systems Simulation and Testing |
| VT | viscous transmission |
| VVA | variable valve actuation |
| WBS | wide base single |
| Wh/kg | watt-hours per kilogram |
| WHR | waste heat recovery |
| ZEV | Zero Emission Vehicle |