Driver loses control of car towing caravan causing it to flip onto its roof

Koroit police Sergeant Pat Day said it appeared the car towing the caravan had swayed and the driver was unable to correct it before losing control.

"The vehicle crossed onto the wrong side of the Princes Highway and into a slight downward drain area," he said.

"The vehicle rolled onto its left side and the caravan flipped over onto its roof."

Sergeant Day said both the driver and passenger were "very, very lucky" to avoid serious injury.

He said both the car and caravan were significantly damaged.

"It's a reminder that if you're towing a caravan to take your time and try and be as experienced as you can," the sergeant said.

There were minor delays on the highway as emergency services worked to clear the road.

It comes after Victoria Police launched its statewide traffic Operation Arid, which is running between midnight Thursday through until midnight Monday.

Police are warning of the dangers of excessive speed and fatigue during the long weekend as new analysis shows a concerning number of motorists killed in single-vehicle collisions.

Data shows 20 people have died in single-vehicle collisions on rural roads this year.

It represents around 40 per cent of the 52 deaths recorded across the entire state so far this year.