Black ice and a jack-knifed lorry led to hour-long delays for motorists on the A80 by Castlecary in the Central Belt, police said.
A build-up of snow caused problems on the M73 and a third major route, the M74, was down to one lane for a large stretch in Dumfries and Galloway.
Several routes in West Lothian were only passable with care and police in the Highlands advised drivers not to travel unless strictly necessary.
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Heavy snow forced the closure of Inverness Airport earlier today and there were delays and cancellations at Edinburgh Airport as staff cleared the runways.
Problems were partly due to closures at destination airports, with flights from Scotland to Manchester, London, France and the US all hit by snowfall on both sides of the Atlantic.
Heavy snow storms in the Highlands and Islands caused widespread travel problems for motorists and ferry passengers, forcing Cal Mac to abandon services from Ullapool to
Stornoway and from Oban to Lochboisdale.
Roads were closed around Tomintoul, Dalwhinnie and Cock Bridge, Traffic Scotland said, and there were no immediate plans to reopen them.
Temperatures were set to plunge to a night-time low of -8C in the Highlands and parts of the north east, and almost everywhere in the country was predicted to remain below freezing into the start of today.
Inspector John Smith, of Northern Constabulary’s road unit, advised motorists not to travel unless it was absolutely necessary.
“There are no current reports of any serious incidents, although there have been some minor collisions,” he said.
“Further heavy snowfalls are forecast and if drivers have to travel they are urged to exercise extreme caution.”
But while conditions in Scotland forced travellers to allow extra time for journeys in the busy pre-Christmas weekend, people in England and
Northern Ireland experienced far worst disruption.
Hundreds of homes in East Anglia were without electricity after snow drifts caused problems for suppliers and some gas supplies were also cut off.
Bookies have now slashed the odds of a white Christmas in Scotland.
Over an inch was recorded in central Glasgow, with more on the hills and outlying areas, and further heavy falls are expected in the coming days.
Glasgow is now the second most likely place in the UK to experience a snowy 25th, according to bookmakers, who have cut the odds repeatedly to a low of 11/8.
Only Aberdeen is more likely to see snow in the big day, with odds of 5/4, while Edinburgh is sitting at 37/25.
One anonymous gambler in Derbyshire is set to win a record £14,700 if it snows on Christmas in Aberdeen, Cardiff and London, after he staked £1,700, a spokesman for betting chain William Hill said.
The whiteout yesterday caused serious problems at Inverness Airport, with some delays in Edinburgh, but Scotland overall managed to avoid the kind of travel chaos currently gripping more
Meteo Group UK, the weather arm of the Press Association, said the cold snap would go on for the next few days.
Cold causes deaths in Europe and America
In the US some states had with record snow - nearly 2 feet in places - and caused at least five deaths.
Blizzard warnings remained in effect last night (SUN) for parts of Rhode Island and Massachusetts, with gusts up to 60 mph. As much as 16 inches of snow is expected to cover parts of southern New England.
Residents of states to the south struggled with the aftermath.
On the cusp of the winter solstice, the storm dropped 16 inches of snow on Reagan National Airport outside Washington on Saturday - the most ever recorded there for a single December day - and gave southern New Jersey its highest single-storm snowfall totals in nearly four years.