Police are investigating the circumstances surrounding a fatal collision in Hopetoun Park near Bacchus Marsh on Saturday evening.
It is believed the driver of a Holden Astra has veered onto the wrong side of the Western Freeway just before 11pm and collided head on with a 4WD.
The female driver of the Astra, who is yet to be identified, was the only occupant of the vehicle and died at the scene.
The male driver of the 4WD is being treated for serious but non-life threatening injuries.
His passengers, a young boy and girl and a male in his 20s were not injured.
The exact cause of the collision is yet to be determined.
Anyone with information regarding the incident is urged to contact Crime Stoppers on 1800 333 000.
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