Try this, comrade:
http://www.detroitmi.gov/Departments...0/Default.aspx
From what I could see, New Years Day is holiday / Sunday hours. It didn't say anything about NYE so I imagine tonight is regular hours. My guess would be that the page you linked to is the old page, Detroit's website layout changed and they forgot to delete the old page. Update your bookmarks / favourites list.
Bookmarks