Here we have gone from 48* Wednesday and Thursday to about 16*, plus we had some local snow overnight. I was intending to go 100 miles east this morning, as I have been for the last few months, but about 30 miles down the road the highway had become a sheet of ice. I continued for about 5 miles, but it becomes a 2 lane road at that point conditions weren't improving so I turned around and headed back to the home terminal. I trust myself on the road, but not other drivers. Considering that in that 5 mile stretch there were 6 vehicles in the ditches, and signs of several others having been removed already it was an easy decision. Only the second time I have had to do that in 36 years as a commercial driver, but I won't risk my safety for freight. My boss informed the senior management and their response was completely supportive.