The Western Freeway has re-opened in both directions between Ballan and Bacchus Marsh, following multiple crashes near Myrniong.
Emergency services attended the scene of several multi-car collisions yesterday afternoon, due to extremely foggy conditions.
One crash involved around 14 vehicles, though no one was seriously injured.
In separate collisions, two men were taken to hospital in a critical condition.
Twenty other people from various crashes were treated for non-life-threatening injuries.
As repairs to the road continue, speeds have been reduced to 60 kilometres an hour in parts, with the Department of Transport urging drivers to remain vigilant for fog between Melton and Ballarat.