By Rachel More

BERLIN, Jan 7 (Reuters) - More than 30 companies across the automotive supply chain have agreed to collaborate on open-source software to develop next-generation cars and cut costs, the German industry lobby behind the initiative said on Wednesday.

Germany's VDA announced the expansion of the initiative at the CES trade show in Las Vegas, where carmakers and suppliers are betting on AI and software to revive an industry struggling with slow progress and high costs.

European auto group Stellantis and truck maker Traton have signed the memorandum of understanding, along with German supplier Schaeffler and chipmakers Infineon and Qualcomm, the VDA said.

They join German carmakers Volkswagen, BMW and Mercedes-Benz, among others, lifting the number of participating firms from 11 when the group was announced last year to 32.

The initiative aims to reduce development and maintenance efforts by up to 40% and speed time to market by up to 30%, the VDA said.

"The growing participation in this collaboration reflects a clear global shift toward open innovation in the automotive industry," said Mike Milinkovich, executive director of the Eclipse Foundation, a co-organiser of the initiative.

(Reporting by Rachel More. Editing by Mark Potter)