Acting Sergeant Tracey Atkins said the driver of a red Mercedes Benz sedan was attempting to overtake a cyclist on Ballarat-Daylesford Road on a bend on the road about 9.10am.

In doing so the 70-year-old driver crossed double lines onto the other side of the road and clipped a white car travelling in the opposite direction.

The impact caused the white car to flip, slide down the roadway and land on its roof while the Mercedes, which was carrying four people, spun sideways.

Multiple police units, ambulances and firefighters from both the Country Fire Authority and Fire Rescue Victoria rushed to the scene.

The 70-year-old man was trapped in his Mercedes for about 40 minutes, before being extricated by emergency services.

Paramedics treated him for rib and lower body injuries until an air ambulance arrived at the scene.

The three passengers from the Mercedes - two women and a man - were transported to hospital in stable conditions, with minor injuries.

The female driver of the white car was also taken to hospital in a stable condition for observation.

The cyclist, meanwhile, was uninjured.

Police closed off Ballarat-Daylesford Road in both directions as a result of the crash, as emergency crews worked to clear the scene.

A new law passed earlier this year requires motorists to allow at least a one-metre distance when passing a cyclist in a speed zone 60km/h or lower and 1.5 metres when travelling at speeds of over 60km/h.

The law allows motorists to briefly cross a painted line to allow this room, but only if it is safe to do so and they have a clear view of the road ahead.

The crash occurred on the last day of the Queen's Birthday long weekend and Victoria Police's road safety Operation Regal.

At the scene of the crash, Acting Sergeant Atkins said police had been urging drivers to take care on the roads during the long weekend.

The four-day operation has involved personnel from the highway patrol, general duties and other operational policing units targeting high-risk driving behaviour such as speeding, alcohol and drug impaired driving, fatigue, driver distraction and failure to wear a seatbelt.

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Police have been assisted by mobile speed cameras, police cars fitted with Automatic Number Plate Recognition technology and a fleet of alcohol and drug testing cars.

With more than 90 lives lost on the state's roads this year, Highway Patrol Acting Senior Sergeant David Whitwell implored people to drive with care and to be considerate of other road users.

"Don't take risks and be patient with other road users, including cyclists and people driving farm machinery," Acting Senior Sergeant Whitwell said.

As part of Operation Regal, police had drug and alcohol tested more than 400 motorists in the Ballarat area by midday on Monday.

Of these, three people were detected driving under the influence of alcohol or drugs.

Aside from this, almost 40 other motorists were detected for offences including speeding, distraction and failure to wear a seatbelt.

Acting Senior Sergeant Whitwell said this was disappointing.

Operation Regal concludes at 11.59pm Monday.

An investigation into the collision is ongoing.

Anyone with any information is urged to contact Crime stoppers on 1800 333 000 or to submit a confidential crime report at www.crimestoppersvic.com.au

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