DETROIT — The General Motors Board of Directors unanimously elected Mary Barra as its next chairman, effective immediately. She succeeds Theodore Solso, who will serve as the Board’s Lead Independent Director.

“At a time of unprecedented industry change, the board concluded it is in the best interests of the company to combine the roles of Chair and CEO in order to drive the most efficient execution of our plan and vision for the future,” Solso said. “With GM consistently delivering on its targets and on track to generate significant value for its shareholders, this is the right time for Mary to assume this role.”

Barra has served as CEO of GM since Jan. 15, 2014, a role she will retain. Solso said that Barra has set a clear vision for the organization over the past two years, formed a strong leadership team from within and outside the company, delivered strong operating results, and led the introduction of breakthrough vehicles and technologies.

“The board has improved the overall governance of the company over the past two years and as lead independent director, I expect to continue to build on this solid foundation,” Solso said. “The board also plans to broaden its active engagement with shareholders as we go forward.”

Prior to becoming CEO in 2014, Barra had served as executive vice president of global product development, purchasing and supply chain since August 2013, and as senior vice president of global product development since February 2011. She was responsible for the design, engineering, program management and quality of GM vehicles around the world.