Understanding Indiana Excise Taxes on Vehicles
If part of the registration fee on your car is based on the value of your car, then that portion is deductible on a Schedule A. After searching for half an hour, I finally ran across this post by Mr Tax Preparer:
According to the Indiana Code 6-6-5 (specifically, IC 6-6-5-3), the County Excise Tax is the part that is calculated based on the value of the vehicle. It would seem that this part is definitely deductible.
This is definitely different than when I lived in New Hampshire. There, they looked up the tax based on the model and year of your car. And that kind of lookup (somehow not based on value) is non-deductible.
Please note that anyone relying on me for tax advice, is nuttier than I am. Contact your tax professional if you want to be sure you know the right answer.