Apparently Indiana has done away with the "Exempt" diesel fuel classification as the price on the sign now matches the pump price!
Have personally verified this at a few different stations in NW Indiana and a local TDI friend of mine has done the same.
Not every station had the exempt classification (primarily was stations that did volume business with big trucks - mainly truck stops and stations located just off major highways) which makes it easier to compare prices now that one does not have to mentally add the extra 28 cents of tax to the exempt sign price to find the true cost per gallon.
Generally speaking though it is still cheaper to refuel in Michigan than Indiana as Michigan's diesel tax is lower since Indiana hiked up their fuel tax this past summer. I live/work close to the state line so popping up to Michigan does not take me out of the way. The difference can be much as 44 cents per gallon recently in my area!
As an aside over by Chicago fuel usually was more expensive over there too but with Indiana's fuel tax increase Illinois is usually cheaper than Indiana now - even in Chicagoland! Only thing is that Illinois fuel is 10% biodiesel while VW officially approves of 5% or less biodiesel content for those of us who have the common rail TDI engines.
Used to be Indiana was a better price than Michigan or Illinois for diesel fuel. I understand Indiana now has the second highest tax rate on diesel these days so things certainly have changed this year.