Hundreds of drivers have spent the night in their cars after heavy snow and ice caused severe disruption.
Parts of the M74 motorway in Lanarkshire were closed for a number of hours, with tailbacks stretching back 12 miles.
Police declared a critical incident with more than 200 motorists trapped in their vehicles as snow hit the area throughout Tuesday evening and into the early hours of Wednesday.
Mountain rescue teams were called in to check on drivers.
The motorway reopened on Wednesday morning but Transport Scotland warned that conditions remained challenging after a "very difficult night".
Sam Sykes, a surveyor from Biggar, South Lanarkshire, said he was stuck on the M74 for around 12 hours - from 6pm on Tuesday until around 5.30am on Wednesday.
"It was really horrible as you would imagine...I got a little bit of sleep but the combination of cold and not knowing if you were going to be moving again restricted that.
"Luckily I am not in work this morning."
First Minister Nicola Sturgeon urged people to be careful in the challenging conditions.
Dozens of schools have been closed in some parts of Scotland and Northern Ireland, while public transport has been disrupted by the weather.
The disruption comes as weather warnings of snow and ice were issued across the UK.
The Met Office has issued yellow "be aware" warnings of snow and ice for much of the country which are valid until Friday.
Looking ahead to Wednesday, meteorologist Alex Burkill said: "It is going to be quite windy as low pressure pushes through tonight and that could bring some snow across parts of Scotland and in particular northern England."