Hands on: Barra, who once ran the Detroit Hamtramck assembly plant, and moved to the CEO role from heading global product development, purchasing and supply chain, tours GMs Kansas factory

Hands on: Barra, who once ran the Detroit Hamtramck assembly plant, and moved to the CEO role from heading global product development, purchasing and supply chain, tours GM's Kansas factory

Having become the first female CEO of a 'Detroit Three' automaker, Mary Barra has pushed through another glass ceiling to be named General Motors' board chairman, effective immediately. She succeeds Theodore (Tim) Solso, who remains the board's lead independent director.

Barra, an engineer, has been GM's CEO since 15 January, 2014.

"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 in a statement. "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."

Solso indicated Barra has set a clear vision for the automaker over the past two years, formed a strong management team from inside and outside the company, delivered strong operating results and led the introduction of breakthrough vehicles and technologies.

He did not mention she has also steered the company well through a difficult period which included voluntarily taking responsibility for the 'ignition switch recall' of millions of cars and the appointment of an independent lawyer to handle US$600m in payouts related to deaths and injuries in crashes associated with the defective parts. This helped victims who could not sue because the switches were installed before the company's 2009 bankruptcy. Barra had to face extensive scrutiny from a Congressional committee and agree a fine of $900m with the US Justice Department.

"[The appoinyment] says she has done a good job and set the right tone for the company," Maryann Keller, an independent auto analyst who wrote two books on GM management under past chairmen Jack Smith and Roger Smith, told Bloomberg. "She takes responsibility for what happens at GM. With past management, it was always the blame game."

On Barra's watch, GM has made a number of strategic decisions, such as pulling out of Russia and ending Chevrolet operations in Europe, Bloomberg noted. It has just announced it will invest $500m in ride-hailing startup Lyft, gaining a major ally in a fast-growing market. In China, GM managed to keep profits stable even as sales in the region slumped. While the car market weakened, the automaker dedicated production to more-profitable sport utility vehicles and higher-priced Buicks, Bloomberg said, adding Barra has also pushed a technology agenda - racing to stay in step with Google's efforts to build a self-driving car and unveiling the Chevrolet Bolt, a pure-electric car, at CES 2016 in Las Vegas this week.

Women held the CEO post at 21 of the Standard & Poor's 500 companies as of mid-December, Bloomberg said, citing Catalyst. About 20 companies had a female chairperson, according to Bloomberg data. Only 11 have women in both roles. 

"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 in GM's statement. "The board also plans to broaden its active engagement with shareholders as we go forward."

Barra said: "I am honoured to serve as chair of the board of directors. With the support of our board, we will continue to drive shareholder value by improving our core business and leading in the transformation of personal mobility."

Prior to being named CEO in 2014, Barra headed global product development, purchasing and supply chain from August 2013, and as head of global product development from February 2011.

She has also worked in human resources, manufacturing engineering, run the Detroit Hamtramck assembly plant, headed competitive operations engineering and in several other engineering and staff positions.

Barra began her GM career in 1980 as a General Motors Institute (Kettering University) co-op student at now-defunct Pontiac. She earned a bachelor's degree in electrical engineering in 1985.