The Department of Revenue shall, on or before the fifteenth day of June of each year, prepare and adopt an assessment schedule of motor vehicles, as defined in this chapter, which such assessment schedule, and no other, excepting as may be hereinafter provided, shall be used by the tax collector of each county and each municipality in the state, in assessing, calculating and collecting ad valorem taxes in each respective jurisdiction on all motor vehicles liable for such tax as authorized by this chapter.

In preparing the assessment schedule, the Department of Revenue may make use of, as a base, the values of the various makes, models, year of manufacture, and types of motor vehicles as adopted by some reputable nationwide agency or association which regularly compiles and furnishes such information as to actual value of the different motor vehicles as to make, model, type and year of manufacture, or by any other method or methods or combination of methods which in its judgment will tend to equalize the assessed value of property of this class with property of other classes in general. These various motor vehicles, together with any special equipment, may be grouped into as many categories as, in the judgment of the Department of Revenue, will be most practical in effecting equalization.

In preparing the assessment schedule, the Department of Revenue shall apply such a percentage to the base value of such motor vehicles which, in its best judgment, will produce an assessed value which will equalize the assessed value of motor vehicles with the assessed value of other property in general, throughout the state, so far as is practical.

The Department of Revenue shall also make necessary corrections and amendments to this schedule from time to time throughout the fiscal year, and in so doing the general procedure set out above shall be followed.