"Be very careful, keep good distances, take it easy and make sure to drive with good time margins. You should always be prepared for slippery sections on the roads," Lennart Mossberg of the Transport Authority told news agency TT.
There were several accidents early Friday morning, including two outside of Stockholm and a single-car accident in southern Sweden. While the slippery conditions were expected ease up by 9 AM in most parts of the country, in the south, the Transport Authority warned, conditions did not look set to improve until around 3 PM.
"Conditions are the worst in the morning, while driving to work. Even if air temperatures are above freezing, there could be minus temperatures on the roads and that's why you have to be very careful," said Swedish Television meteorologist Nils Holmqvist.
The Transport Authority warned of fresh frost forming Friday afternoon along the northern coastline and after 9 PM large parts of the Uppsala and Södermanland regions in central Sweden, as well as parts of Jämtland and Dalarna in the west, will experience icy road conditions that could last until Saturday.