Motor Vehicle Tax

You can deduct any tax on the value of property. So you cannot deduct a state fee based on anything else (flat fee, weight, size, etc.).

Haven't done CT in a long time, but the towns used to bill you for excise tax based on the value of the auto. (Check your town bill for "mill rate." That 1/10th of 1% and means it is calculated on value.

TT will ask you about that and will carry it over to your CT return if allowed (most states don't all that).

Also to deduct this type of deduction you must "itemize" and that only makes sense if the total of your itemized deductions is larger than the "standard deduction." The SD is very  large now ($12k single, $24 married/joint in 2018). So very few people will itemized.