Luke Nardini, from Narrogin in Western Australia, was driving a BMW M4 on Highway 84 near San Francisco, when he collided head-on with another car on a tight blind turn.
One man and one woman were killed, while two others were hospitalised.
Nardini, 31, suffered minor back injuries.
US police suggested that Nardini may have unknowingly been driving on the wrong side of the road.
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He is currently in police custody and has been charged over the crash.
If convicted, he could face up to two years in jail.
Nardini’s mother and brother are already in the US to support him through the legal process, including a bail application process in two weeks, while Narrogin locals have submitted character references on his behalf.