Upon adoption of a system of classification of taxable property by the city of Cranston, all ratable property in the city of Cranston shall be classified by the assessor as follows:
(1) Class 1: In the city of Cranston, all ratable real estate and tangible personal property.
(2) Class 2: In the city of Cranston, all motor vehicles and trailers subject to the excise tax created by chapter 34 of title 44.