In the State of Rhode Island, motor vehicles are assessed an excise tax that is one year in arrears. What this means is, when you recieve your motor vehicle tax bill in June, that bill represents the number of days that vehicle was registered to you the previous year. Therefore, if you sold your car on March 1st of the current year, you will still recieved a tax bill for all of the days owned in the prior year, plus you'll recieve a tax bill next year for the number of days owned between January 1st and March 1st.
However, the excise tax is actually for the privilege of registration based on the valuation of the motor vehicle that registration is attached to. So if you sell your car but do not return the plates or properly transfer them to another vehicle, the excise tax will continue until either you return the license plates, or the registraton of those plates expire.
How to Cancel Your Registration/Plates
The DMV requires you to surrender your license plates upon cancellation.
Per the Rhode Island Department of Motor Vehicles, to properly cancel your plates/registration, you must:
Cancel plates at any DMV branch location or at a AAA branch office (members only). Out of state plates must be returned to the original state.
By Mail: Send the cancelled plates to the Division of Motor Vehicles Attn: Plates, 600 New London Avenue, Cranston RI 02920. Use registered mail with a return receipt request. To request a plate cancellation receipt (Form TR-3), please include a postage paid, self-addressed envelope. Keep the plate cancellation receipt to avoid future property tax claims if your city or town neglects to remove you from their records.
Lost or stolen plates must be reported to your local police department.
How Motor Vehicles are Valued/Assessed
The valuation of your vehicle is based on the N.A.D.A. (North America Dealer's Associaiton) valuation guide books published in January of each year. The Town of Tiverton then 'discounts' that value by $6,000 (for a full year's registration, pro-rated otherwise) which is the highest in the State of Rhode Island. Most other communities only discount their vehicles by $500. This represents a potential savings of $105.27 per vehicle you own. See below regarding the phase out of the Motor Vehicle tax for updated valuation methodology.
In 2017, the General Assembly passed House Bill 5157, Article 11 which calls for the phase-out of the motor vehicle (excise) tax. A good explaination of Article 11 can be found HERE.
Accordingly, in 2018, your motor vehicle will be assessed at 90% of the N.A.D.A. book value, further reduced by a State Exemption of $2,000, and finally, a $4,000 exemption provided by the Town of Tiverton.