Motorists continue to face difficult conditions after heavy snow across parts of Scotland caused road closures.
A Met Office yellow warning for ice will be in place overnight and for all of Friday for mainland Scotland.
The A9 at Dunblane was closed due to snow but has now reopened, while driving conditions on the M90 and M8 were reported as difficult.
There have also been problems in the Scottish Borders where up to a foot of snow fell overnight.
Traffic Scotland has reported difficult driving conditions on the M77 at Fenwick, M80 around Cumbernauld and the A9 at Greenloaning.
In the Borders several lorries got stuck on the A7 between Selkirk and Hawick, while difficult driving conditions were also reported on the A68 at the Carter Bar and Soutra.
There were also delays on the A83 Old Military Road diversion and the A82 at Tyndrum.
Meanwhile, police have urged drivers to properly clear their car windscreens before setting off in the wintry conditions.
Officers in Dumfries and Galloway shared a picture of a driver they stopped and charged for failing to do this.
Road Traffic Officers stopped a red Citroen Nemo where the windscreen & windows were fully frozen over.— DumfriesGPolice (@DumfriesGPolice) January 14, 2021
The driver's visibility was very poor & he could have been involved in an RTC. The driver was charged accordingly.
Please ensure your car is fully defrosted before travel. pic.twitter.com/ubfJ3SH31n
People should only be leaving home to make essential journeys in parts of Scotland under level four Covid measures, under current Scottish government lockdown regulations.
Ch Supt Louise Blakelock, of Police Scotland, said: "Government guidance on only travelling if your journey is essential remains in place and so with an amber warning for snow, please consider if your journey really is essential and whether you can delay it until the weather improves.
"If your journey really is essential, plan ahead and make sure you and your vehicle are suitably prepared by having sufficient fuel and supplies such as warm clothing, food, water and charge in your mobile phone in the event you require assistance."
Police in Shetland have also warned of ice badly affecting roads on the islands.
ScotRail said its services could be affected, particularly on the Highland mainline.
Scottish Borders Council said the effects of the adverse weather could cause disruption into Friday morning.
Emergency planning officer Jim Fraser said: "With widespread snow and some freezing rain possible over the course of Wednesday and Thursday, there is the strong potential for disruption across our road network and communities."
⚠️The @Metoffice has issued an Amber weather warning for heavy snow across parts of the country.— Michael Matheson MSP (@MathesonMichael) January 13, 2021
Please follow the advice from @policescotland and @trafficscotland
For live updates follow the @metoffice & @trafficscotland.
Please take care. Stay #WeatherAware https://t.co/6ym17sEbd0
Some of the deepest snowfalls in recent weeks have been in the Highlands, including the Cairngorms.
Earlier this month, the UK had its coldest night of the winter so far after a temperature of -12.3C was recorded in the north west Highlands.
The temperature was recorded at Loch Glascarnoch, near Garve, south of Ullapool in Wester Ross.
The record lowest temperature in the UK is -27.2C, which was recorded in Braemar, Aberdeenshire, in 1895 and 1982 and at Altnaharra in the Highlands in 1995.