It’s roughly 8 hours between the two with a time change. Of course, if there is snow, from Ann Arbor to Chicago can be really dicey. Not that from Chicago to Madison is a cake walk either. Getting through Chicago from Ann Arbor to Madison is a slow go. It’s often backed up from Sox Park until you get to the Cave. And then again at the Kennedy/Edens spilt to O’Hare. All this could add anywhere from an hour to several hours depending on traffic and weather. Mid-March isn’t usually all that snowy but you never know with lake effect on MI side.