What is now I-41 between De Pere and Kaukauna, WI (then US 41) was upgraded from two lanes to a more than adequate four lane surface expressway in 1968. It is now programmed for upgrading to a six lane urban profile freeway starting in 3-4 years.
Mike
I remember taking the old US 41 with my grandparents from Green Bay to Milwaukee when I was a kid. My grandfather wanted to go that was because was all four lanes as opposed to my dad's preference of taking WI 57. My grandfather died in 1966. I think
this site has the date right in being expanded in 1964. It was not underbuilt at the time and has been upgraded as needed over the years with additional exits and finally to full freeway.
I don't disagree that it needs to be six lanes today.
Underbuilt on I-41 is the interchange with US 151 which should have free-flowing ramps between the interstate and expressway. The stoplights on US 151 are ridiculous after driving nonstop from Madison and encourages drivers to use WI 26 instead. I'd actually prefer a four lane WI 26 with a bypass of Rosendale, but it seems like Wisconsin's most notorious speed trap will continue for the time being.