Cummins and Westport Extend Joint Venture Agreement and Create Technology Partnership

VANCOUVER, Dec. 16, 2003 -- Westport Innovations Inc. (TSX:WPT) and Cummins Inc. of Columbus, Indiana, announced today the extension of their joint venture agreement to develop markets for alternative fuel engines. In addition, the two companies have signed a Technology Partnership Agreement that creates a flexible arrangement for future technology development between Cummins and Westport.

Tim Solso, Cummins Chairman and Chief Executive Officer, said, "We are pleased to continue our partnership with Westport. Over the past three years, Cummins Westport has built a business that we believe can build on the strong customer relationships it has developed as well as achieve a sustainable bottom line. We wish the CWI team great success in this exciting venture and we look forward to this new partnership with Westport to build this business."

Cummins Westport Inc. (CWI) was originally formed as a joint venture company in March 2001 to explore a range of product and technology opportunities using natural gas as fuel. Westport provided personnel, financing and key technologies for the venture, while Cummins provided an existing product line, manufacturing, product distribution and customer service functions, as well as key management and engineering personnel.

CWI will continue as a 50:50 joint venture. Cummins has agreed to convert its preferred share interest in CWI, and as of January 1, 2004, both Westport and Cummins will hold equal numbers of common shares in CWI.

Westport and Cummins today also signed a detailed framework agreement for collaboration on a range of technology development programs.

Dr. John Wall, Cummins Chief Technical Officer, said, "Over the past three years Westport and Cummins have together created advances in understanding how we can create cleaner internal combustion engines that also deliver the performance our customers expect."

CWI's achievements include the development and release of the industry- leading "Plus" line of mid-range natural gas and propane engines, significant technical achievements in the development of low-emissions engines that maintain high performance and fuel efficiency, successful technology demonstrations in both trucking and power generation and increased product sales in markets around the world, including China.

CWI's engines have proven successful in varied customer markets and are in service in 18 countries worldwide. In North America, CWI is now the leader in natural gas transit buses. Transit agencies in large cities such as Los Angeles, Tacoma, Boston, San Diego and Washington have selected CWI engines. In China, cities such as Beijing and Xian have purchased multiple orders, in addition to six other cities that have received their first shipments in the past year. These eight Chinese cities have a combined transit fleet of nearly 50,000 buses.

David Demers, Westport's President & Chief Executive Officer, added, "We are proud of our continued relationship with Cummins and we are committed to supporting CWI's future success. CWI is unique in our industry - a true collaboration between a technology development company and a global leader that has allowed for the creation of a focused, disciplined management team that can deliver market-leading alternative-fuel products and services around the world. We believe CWI will see significant growth for years to come, especially in expanding international markets such as China and India."

A copy of the Amended and Restated Joint Venture Agreement is attached to the Material Change Report filed by Westport with the Canadian Securities Regulators. The Material Change Report is available on the Westport website at www.westport.com or on the SEDAR website at www.sedar.com.

A conference call will be held on Wednesday, December 17, 2003, at 7:30 am (Pacific Time) to discuss this announcement. To access the conference by telephone, call 1-888-359-6744 no later than 7:25 am. Alternatively, the conference call webcast can be accessed through www.westport.com by following the link on the Investor Information menu. Replays will be available shortly after the conference call concludes.

Westport Innovations Inc. is a leading developer of gaseous fuel engine technologies. It develops, manufactures and sells a wide range of engines for commercial transportation applications, such as trucks and buses through Cummins Westport Inc., its joint venture with Cummins. Technology development alliances are in place with a number of other leading engine manufacturers, including Ford, MAN, Isuzu, and BMW to develop engines that operate using cleaner-burning fuels such as natural gas, propane, hydrogen and blended fuels such as HCNG.

Cummins Inc. is a global power leader in engines, electrical power generation systems, filtration systems and related technologies. For further information on Cummins Inc., please visit www.cummins.com or contact Jason Rawlings, Director of Public Relations at 812-377-7719 or Jason.F.Rawlings@Cummins.com

Note: This document contains forward-looking statements about Westport's business, operations, technology development or to the environment in which it operates, which are based on Westport's estimates, forecasts and projections. These statements are not guarantees of future performance and involve risks and uncertainties that are difficult to predict, or are beyond Westport's control. Consequently, readers should not place any undue reliance on such forward-looking statements. In addition, these forward-looking statements relate to the date on which they are made. Westport disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise.

  For further information on Westport Innovations Inc., please contact:

  Gordon Neal
  Director, Investor Relations
  Phone: 604-718-2046   Fax: 604-718-2001
  Email: invest@westport.com   Web: www.westport.com