Police have urged motorists to drive with caution in the north of Scotland as overnight sleet and snow is forecast.
They warned that there could be significant drifting of snow on high routes like the A9, A95 and A93.
Strong winds are also expected to lead to bridge closures and disruption to ferries.
A Met Office yellow warning for snow and ice in parts of the north of Scotland is valid from 18:00.
Police Scotland said the parts of the country most likely to be affected by the wintry weather were:
- Aberdeen City
- Perth and Kinross
- The Western Isles.
Ch Insp Stewart Mackie said that drivers and pedestrians should expect longer journey times and icy patches could form on untreated surfaces.
He added: "The current challenging conditions continue, with the north of the country facing poor driving conditions over the next day or so.
"While there is likely to be an easing of conditions towards the end of the week, during Friday night and Saturday morning a band of rain and sleet will move east across Scotland giving a spell of snow over upland areas.
"Conditions will be poor with snow for a time on higher parts such as A9, with winds also freshening. Later on Saturday the rain and hill snow will turn more showery.
"If you are travelling on the roads you should ensure you and your vehicle are adequately prepared for the conditions, making sure you have sufficient fuel and supplies such as warm clothing, food and water in the event you are delayed for several hours.
"Charge your mobile phone and plan your route as well as alternative routes. Listen to media broadcasts, especially local radio, and visit the Traffic Scotland website."
Our #Gritters are getting things moving #M74 Jct 11-12 nr Millbank. Please #DriveAware and keep checking @trafficscotland & @ScotTranserv for latest updates @RHANews @newsfromfta @POFerriesFR8 @transcotland pic.twitter.com/SHlMg4R4Xp— Scotland TranServ (@ScotTranserv) January 31, 2018
Earlier, vehicles queued on the M74 at junction 12 Millbank and junction 13 Abington, following a period of snowfall.
Traffic Scotland said vehicles HGVs were struggling with traction on the northbound carriageway and gritters were on scene.
A yellow "be aware" warning of snow and ice was in force across southern, western, central and north Scotland until 18:00.
A third weather warning for ice in western, central and southern Scotland will be in force from 18:00 until 10:00 on Thursday.
The warning said: "Following a spell of rain, sleet and snow, temperatures will fall quickly allowing ice to form on untreated surfaces.
"Further showers of rain, sleet and snow will follow in the west on Thursday morning, potentially diluting overnight treatments.
"Some roads and railways are likely to be affected with longer journey times by road, bus and train services.
"Some injuries from slips and falls on icy surfaces are possible."