| AAA | American Automobile Association |
| AAR | Association of American Railroads |
| AASHTO | American Association of State Highway & Transportation Officials |
| ADA | Americans with Disabilities Act |
| ART | Arlington Transit System |
| ARTS | Automated Routing Transportation System (WMATA’s customer service database) |
| APTA | American Public Transportation Association |
| AQPAC | Air Quality Public Advisory Committee |
| AVI | Automated Vehicle Identification |
| BATA | Ballston/Rosslyn Area Transportation Association |
| CAAA | Clean Air Act Amendment |
| CAC | Citizens Advisory Committee |
| CCWP | Commuter Connections Work Program |
| CFD | Committee for Dulles |
| CIP | Capital Improvement Program |
| CLRP | Constrained Long-Range Plan |
| CMAQ | Congestion Mitigation & Air Quality Improvement Program |
| CO | Carbon Monoxide |
| COG | Metropolitan Washington Council of Gov’t |
| CTB | Commonwealth Transportation Board |
| CUE | CUE Bus (City of Fairfax) |
| DASH | Alexandria Transit Company |
| DATA | Dulles Area Transportation Association |
| DCDPW | D.C. Department of Public Works |
| DCRA | Dulles Corridor Rail Association |
| EPA | US Environmental Protection Agency |
| FAMPO | Fredericksburg Area Metropolitan Planning Organization |
| FHWA | Federal Highway Administration |
| FRA | Federal Railroad Administration |
| FTA | Federal Transit Authority |
| GIS | Geographic Information System |
| GMU | George Mason University |
| GPS | Global Positioning Satellite System |
| GRH | Guaranteed Ride Home |
| GSA | General Services Administration |
| HJR | House Joint Resolution |
| HMOF | Highway Maintenance and Operations Fund |
| HOT Lanes | HOV-Free/Toll Other |
| HOV | High Occupancy Vehicle |
| ISTEA | Intermodal Surface Transportation Efficiency Act of 1991 |
| ITS | Intelligent Transportation Systems |
| LOV | Low Occupancy Vehicle |
| MARC | Maryland Rail Commuter Service |
| MDOT | Maryland Department of Transportation |
| MIS | Major Investment Study |
| MOU | Memorandum of Understanding |
| MPO | Metropolitan Planning Organization |
| MSA | Metropolitan Statistical Area |
| MTA | Maryland Transit Authority |
| MWAA | Metropolitan Washington Airports Authority |
| MWAQC | Metropolitan Washington Air Quality Committee |
| MWCOG | Metropolitan Washington Council of Governments |
| NEXTEA | Re-authorization of ISTEA |
| NHS | National Highway System |
| NOx | Nitrogen Oxide |
| NPS | National Park Service |
| NTD | National Transit Database (Formerly Section 15 Data) |
| NVPDC | Northern Virginia Planning District Commission |
| NVRC | Northern Virginia Regional Commission ( Formerly NVPDC) |
| NVTA | Northern Virginia Transportation Alliance |
| NVTC | Northern Virginia Transportation commission |
| O3 | Ozone |
| Proffer | Freely Offered Improvements |
| PRTC | Potomac and Rappahannock Transportation Commission |
| PTF | Priority Transportation Fund (VDOT funding program) |
| RADCO | Rappahannock Area Development Commission |
| RFP | Request for Proposals |
| RSTP | Regional Surface Transportation Program |
| SCC | State Corporation Commission |
| SIP | State Implementation Plan |
| SJR | Senate Joint Resolution |
| SOV | Single Occupant Vehicle |
| STARS | Surface Transportation Authority & Regulatory Act |
| STIP | Statewide Transportation Improvement Program |
| TAGS | Transportation Association of Greater Springfield |
| TCC | Transportation Coordinating Council |
| TEA-21 | Transportation Efficiency Act for the 21st Century |
| TERM | Transportation Emissions Reduction Measure |
| TIP | Transportation Improvement Program |
| TLC | Transit Link Pass between MARC, Metro and VRE |
| TMA | Transportation Management Association |
| TPB | Transportation Planning Board of the National Capital Region |
| TRB | Transportation Research Board |
| TRC | Transportation Research Council |
| TRDI | Transit Ridesharing Development Initiative |
| TRIP | Train Information Provider |
| TRIP II | Toll Road Investors |
| TSCP | Transportation Service Coordination Plan |
| TTF | Transportation Trust Fund |
| TYTRAN | Tysons Transportation Association |
| UPWP | Unified Planning Work Program |
| US DOT | US Department of Transportation |
| VACO | Virginia Association of Counties |
| VDOT | Virginia Department of Transportation |
| VDRPT | Virginia Department of Rail and Public Transportation |
| VOCs | Volatile Organic Compounds |
| VPSI | Van Pool Services, Inc. |
| VRE | Virginia Railway Express |
| VRTA | Virginia Regional Transit Association |
| VTA | Virginia Transit Association |
| WABA | Washington Area Bicyclist Association |
| WATF | Washington Airports Task Force |
| WMATA | Washington Metropolitan Area Transit Authority |
| WMTIS | Washington Metropolitan Traveler Information Service |
| WSTC | Washington Suburban Transit Commission |