cars began breaking when they hit a wall of fog near Interstate 90's intersection with U.S. Highway 12/18, Wisconsin State Patrol Lt. Laurie Steeber said. A semi-truck came up behind them and began plowing into vehicles, she said. One person was killed.
Erik Kispert estimated he was going between 65 and 75 mph when he saw brake lights ahead in the fog.
Source
Disclaimer: Colorization, mine.
Having been a professional driver taking railroad crews to their assignments, I have to stress that failure to obey speed limits, failure to drive with respect for "fellow drivers" and failure to adjust for any predicted weather forecasts allows individuals to abuse their driving privilege. In this case, lives were lost!