| ABMARC | Australia |
| Advanced Engine Technologies Corporation | USA |
| Aeris Analytics LLC | USA |
| Andover Technology Partners | USA |
| Ansys Inc. | USA |
| aurigna consulting GmbH | Germany |
| Automotive Consulting Group, Inc. | USA |
| Automotive Industry Data Ltd. | UK |
| AVL List GmbH | Austria |
| BMT Fleet Technology Ltd | Canada |
| Convergent Science Inc. | USA |
| Crown Engineering | USA |
| ECO Inc. | USA |
| Ecotraffic ERD3 AB | Sweden |
| Emissions Consulting Ltd. | UK |
| Emissions Guru Inc. | USA |
| Emissions Services Unlimited Inc | USA |
| Emissol LLC | USA |
| Emisstar LLC | USA |
| Engine, Fuel, and Emissions Engineering, Inc. | USA |
| EngSim Corporation | USA |
| Environex Inc. | USA |
| Exothermia SA | Greece |
| FEV GmbH | Germany |
| Frazier, Barnes & Associates | USA |
| George Lester Inc | USA |
| hte GmbH | Germany |
| IAV GmbH | Germany |
| Integer Research | UK |
| Integral Powertrain Ltd. | UK |
| Ironman Parts & Services | USA |
| LiquidPiston, Inc. | USA |
| Lotus Engineering | UK |
| M.J. Bradley & Associates | USA |
| MacDonald Consulting | USA |
| MARC-IV Consulting, Inc. | USA |
| Meszler Engineering Services | USA |
| Michael P. Walsh | USA |
| NCM Underhallsteknik AB | Sweden |
| Nisymco Inc. | Canada |
| OceanAir Environmental, LLC | USA |
| Peeples Consulting Associates, Inc. | USA |
| Power Systems Research | USA |
| Process Engineering Associates, LLC | USA |
| Prodrive Limited | UK |
| Punch Torino S.p.A. | Italy |
| R.L. Polk & Co. | USA |
| Rhein Associates, Inc. | USA |
| Ricardo Group plc | UK |
| Ricardo-AEA Ltd. | UK |
| RMH Consulting | USA |
| Roben Automotive Sp. z o.o. | Poland |
| Sierra Engineering Services | USA |
| Southern Research Institute | USA |
| Southwest Research Institute | USA |
| Superior Process Technologies | USA |
| TAUW bv | The Netherlands |
| Technology and Engineering Mgm | USA |
| Testing World.net Ltd. | UK |
| TTM Andreas Mayer | Switzerland |
| Unlimited Design International, Inc. | USA |
| Valient Automotive Market Research | USA |
| WTZ Rosslau GmbH | Germany |
| XRD Inc. | USA |