Hundreds of travellers also faced disruptions when a train broke down and rail signalling problems affected services in and around the Glasgow.
Snow partially closed the M74 and forced Glasgow-bound motorists to drive in single file between Hamilton and Lesmahagow in South Lanarkshire in the build-up to rush hour.
Businessman Nigel Cockburn, 46, said: "Only the inside lane was passable. There were times when I was doing no more than 20mph."
Hundreds of rail passengers were left out in the cold when a train heading for the city broke down at Airdrie, South Lanarkshire, while signalling problems disrupted services at Motherwell.
Office worker Fiona McMerriel, 51, said: "ScotRail is cancelling services with little or no warning."
A Scotrail spokesman said: "There was disruption to services through Bearsden, caused by the effects of signalling problems at Motherwell." He claimed most services through Bears-den "ran as normal".
Passengers on a Bathtgate-Helensburgh train were ordered off at Airdrie and told a power failure was to blame.
Legal secretary Lauren Dempster, 39, said: "These things happen but communication between Scotrail and its passengers is poor."
Rail chiefs apologised to commuters, with Network Rail blaming frozen signals for problems. It said the system was back to normal by mid-morning.
Chiefs at road firm AMEY said accidents caused "significant delays" in South Lanarkshire, at junciton 9 at Kirkmuirhill and junctions 4 and five, at Maryville and Raith.
A spokeswoman said the motorway had been gritted at 2.30am and as treated as required.