The levy of such a grade separation tax is authorized if the majority of the votes cast on the specified proposition are in favor thereof. The county clerk thereafter shall extend the tax upon the books of the collector of taxes in each of the years of the term specified in the ordinance in the manner provided by law for the extension of the taxes of the municipality, whether or not the tax in each of those years is included in the municipality’s annual tax levy ordinance, as that tax levy ordinance is passed by the corporate authorities of the municipality and certified to the county clerk. This annual tax shall be exclusive of and in addition to the aggregate amount of taxes authorized by Section 8-3-1.