1. AB Volvo
2. Agility Fuel Systems Inc.
3. Beiqi Foton Motor Co. Ltd.
4. Clean Air Power Ltd.
5. Clean Energy Fuels Corp.
6. CNH Industrial NV
7. Cummins Inc.
8. Daimler AG
9. Dongfeng Motor Group Company Limited
10. Landi Renzo SPA
11. Navistar Inc.
12. PACCAR Inc.
13. Quantum Fuel Systems LLC
14. Robert Bosch GmbH
15. Shaanxi Automobile Group Ltd
16. Westport Innovations Inc.