Motorists are being encouraged to park carefully ahead of the predicted snowfall in Lancashire.
The county's highways teams has issued the warning to ensure that gritters can do their job properly.
They've wanted that parts of some gritting routes often go untreated because drivers don't leave enough room for vehicles to get past.
This comes after the Met Office issued a yellow weather warning across the North West for snow and ice on Tuesday and Wednesday.
Temperatures are also forecast to stay low for the rest of the week, with the general outlook showing the prospect of further wintry weather to follow.
Dwayne Lowe, Lancashire County Council highways manager, said: "Our drivers have real problems trying to get through on parts of some gritting routes because people are badly parked.
"We're concerned that some roads which should be gritted could become icy over the coming days if the gritters can't get through.
"When snow is forecast we often put down a lot of grit to try to prevent the snow from sticking, and we won’t be able to do that in some places if people are parked in the way."
According to Lancashire County Council, parked cars are most often a problem for the gritters on residential streets in towns and villages, with drivers saying they can't treat some hotspots around 90% of the time.
Parking on corners is a particular problem as it means the gritters don't have room to turn.
The gritters typically used in urban areas are around 3 metres wide and 8m long, however if a plough is fitted to clear snow, the gritter becomes 3.2 metres wide and 9.5m long.
On top of the 1,800 miles of priority roads which are gritted whenever a freeze is forecast, the county council has also identified the second most important roads which are treated during periods of continuous ice and snow, but only during daylight hours and after the higher priority roads have been cleared.
These routes include many residential roads where poorly parked cars could block access for the gritters.
County Councillor Keith Iddon, cabinet member for highways and transport, added: "I understand that people need to be able to leave their cars somewhere, and there is pressure on parking in some areas, however I'd ask everyone to make sure they are leaving enough room for a large vehicle to pass.
"If a gritter can't get past, neither will some emergency services vehicles, and I'd ask people to consider the potential consequences.
"Our gritter drivers take their task very seriously and do a great job in sometimes dangerous conditions. I'd ask everyone to help them and everybody who uses the roads by thinking about how they park."
