Macedon Ranges Highway Patrol Sergeant Brad Hall said a number of conditions had to be met for the roads to develop an imperceptible, icy surface.

And he said the part of the world in which he was based was particularly prone to them, compared with areas such as Bendigo.

As the overnight temperatures drop and the risk of black ice forming on roads in the Macedon Ranges rises, police are spreading safety messages they hope will prevent serious road trauma.

Highway patrol members from Bendigo to Kyneton have been running extra patrols in the Macedon Ranges since May 1. 

As they encounter drivers, Sergeant Hall said police had been making a point of discussing the need to drive to conditions in the cooler months.

The probability of black ice is among the conditions police have urged motorists to consider.

“Bridges are where people need to take the most amount of caution,” Sergeant Hall said.

He said the early hours of the morning could also be particularly fraught.

“The best thing you can do is drive slowly in the first place,” Sergeant Hall said.

“The worst possible thing you can do is hit the brakes.”

The sergeant encouraged motorists faced with black ice to continue driving in a smooth, straight line and avoid any sudden movement such as turning hard, accelerating or braking.

“The potential for serious road trauma out there is quite high,” he said 

RELATED: Black ice caused cars to slide off Calder Freeway

It had been some time since he believed black ice had contributed to a serious road incident.

But Sergeant Hall said there were a number of run-off-road collisions each year, in which the phenomenon could have been a factor.

He estimated police had spoken to more than 2500 people since Operation Tinsel, the proactive policing initiative targeting black ice, started.

The sergeant expected that number would more than double by the time the operation ended, on June 30.

“The focus is on the Calder Freeway, but black ice can occur anywhere in the Macedon Ranges,” he said.

Operation Tinsel is believed to be unique to the region.

RELATED: Do you know what to do if you hit black ice while driving?

Bendigo Highway Patrol Sergeant Mick McCrann reiterated that motorists ought to drive to the conditions, not the speed limit – particularly following weather events that might affect the roads.

“You need to modify your driving to be safe,” he said.

He said visibility started within the vehicle, and encouraged people to ensure their windows and windscreens were clear before driving – especially if their vehicles had been parked outside.

Police have also encouraged motorists to report any stretches of black ice, so other motorists could be made aware of the risks.

As black ice is largely imperceptible from a distance, Sergeant Hall urged people to take heed of any ice warning devices along their journey.

He said a number of the devices were in place along the Calder Freeway in the Macedon Ranges, and other roads.