The best answer to this Kentucky specific question was located here https://ttlc.intuit.com/questions/2588802-how-to-claim-a-new-car-on-your-taxes
In short, no the usage tax is not deductible in Kentucky. Only the Advalorem Tax is.
Taken directly from the link above, here is an example for you.
*** Kentucky
Usage Tax: 365.85 #### is it annual?
Reg. Fee: 6
Title Fee: 9.00 (3 state fee and 6 was clerk fee)
Total paid at registration was 380.85
If
you look on your car registration, usage tax is listed first, then
registration fee, then title fee, then ad valorem tax. The usage tax is
sales tax and cannot be deducted. Ad valorem tax is property tax and CAN
be deducted. The registration, title and clerk's fees cannot be
deducted. If it was a new car, the ad valorem tax may have been paid by
the dealer or previous owner for the year and may not be listed on your
fees, so you wouldn't have any to deduct on taxes for the year. The next
time you register the car, you will pay ad valorem tax (in KY it is a
yearly fee paid at the time of registration) and you can deduct it for
that year.
I'm not sure anyone has addressed the issue of deducting
KY's Vehicle Usage Tax, at least not with specificity. The IRS allows
taxpayers to choose whether they will deduct the State Income Tax they
paid or the State Sales Tax they paid. If one chooses to deduct Sales
Tax, they can deduct the actual amount paid (lots of record keeping), or
they can use a table. On top of that, they can deduct Sales Tax paid
on certain large purchases, such as a vehicle. The KY Vehicle Usage Tax
is collected just like a Sales Tax -- it is charged on the sale of the
vehicle, and it is based on 6% (the Sales Tax Rate) of the value. The
IRS has some guidance about "Compensating Use Taxes" which seems to say
that the Usage Tax would qualify as a sales tax. Look at 26 USC 164.
