Make a U-TURN and go back to Madison.
U.S. 12 is an expressway from I-90 to CTH N, which is about 3 miles. It was converted from 2 lanes in 1998. The section of U.S. 12 from CTH N to Cambridge was also reconstructed as a better 2-lane. Eventually, U.S. will be a 4-lane facility from Madison to Chicago, but that is a ways into the future.