An unlucky woman on a motorway in Sydney, tried to avoid a big dog crossing the motorway, in the process swerves and jumps the median and crashes to death.

Police were called to last night’s crash – on the M4 motorway, just east of the Prospect Road off-ramp – about 8.45pm.

They found the woman’s silver hatchback on its roof and woman – the car’s only occupant – already dead.

Witnesses told police the car was travelling in the lane closest to the centre of the road when it swerved to miss a large dog.

The car then crossed three lanes and hit a guard rail before it flipped and came to rest on its roof, police said.