Drivers in southern Scotland have been asked to take extra care as overnight temperatures were reported at -18C.
The bitter freeze prompted police to warn that grit would be less effective than usual on roads across the Scottish Borders and Dumfries and Galloway.
Motorists were asked only to make essential journeys and to use "extreme caution" if travelling.
All routes across both regions were said to be passable with care despite the icy conditions.
Many roads have been affected by snow in recent days which has not cleared due to the low temperatures.
Among the lowest reported was at Cardrona in the Borders with -18C.
Police said that although main routes had been treated with grit it was unlikely to have any "great effect" and roadways would remain "slippery".