BMW

 The car giants said they would work together to develop electric motors, transmissions and power electronics.

Both firms have struggled to maintain profit margins amid falling car sales and higher costs as well as the need to invest in future technologies.

Car firms are being forced to make low emission vehicles to meet more stringent anti-pollution rules.

There have been a number of similar tie-ups aimed at sharing the costs of developing electric cars.

The three firms will collaborate on the systems needed to make cars that can navigate without any help from a human driver.

The vehicles will be capable of driving safely along major roads as well as in suburban and inner city areas.

BMW said it hoped the collaboration would mean it could put robot cars into production by 2021.

The research partnership was announced on the day when US officials begin an investigation into a fatal car crash involving a Tesla Model S, to which self-driving technology could have contributed.

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