Further travel disruption highly likely - avoid travel at peak times if possible.
Travellers are being warned of a high risk of disruption, after the Met Office upgraded its weather warning for parts of south west and central Scotland.
The "be prepared” amber warning is in place for wide parts of the country, including Strathclyde, Central, the Lothians, south west Scotland, Tayside and Fife from 07:00 until 22:00.
Traffic Scotland is providing regular updates on social media, as well as through its website and radio broadcasts, with travellers being asked to check the latest information before they set off.
The Multi Agency Response Team (MART), involving partner organisations, such as Police Scotland, continues to monitor conditions and make sure that the public has the latest information.
The Scottish Government’s Resilience operation (SGoRR) will meet this morning to receive the latest update on the situation.
Transport Minister Humza Yousaf said:
"An updated and upgraded Met Office warning for Amber for heavy snow covering the west and southwest has been issued this morning. This will impact on the AM and PM rush hour and throughout the day.
"SGoRR is up and running and colleagues are in close contact with TS Resilience and MART teams and the Police Scotland multi-agency response team in Glasgow, as we have been throughout the night.
"Motorists should consider avoiding peak journey times and whether they can delay or avoid travelling.
"Our winter maintenance teams are continuing to prepare the trunk road network and stand ready to react to changing conditions, treating roads and helping motorists where required.
“My advice, as always, is to take extra time to plan your journey, listen to police advice and drive to the conditions. Motorists can use the Traffic Scotland mobile website - my.trafficscotland.org - to get the latest information on the move, as well as check the @trafficscotland twitter page for updates.
“If you’re travelling by rail, ferry or air, please check with your operators to make sure your service has not been affected by the conditions.”
The Scottish Government’s Ready Scotland campaign provides the public with a range of advice and information on preparing for winter weather. Further information is available at www.readyscotland.org
For real time journey information visit www.trafficscotland.org, follow @trafficscotland on Twitter or call 0800 028 14 14.
The full Alerts, including the Chief Forecaster's Assessment and a map showing the areas included in the Alerts, are available at http://www.metoffice.gov.uk/public/weather/warnings/