In class one counties, not having a charter form of government, the special road and bridge tax authorized by Section 12, Article X, of the Constitution of Missouri and arising from and paid upon all property, including real estate lying and being wholly within the corporate limits of each incorporated city, town and village, and upon tangible personal property of the residents of each incorporated city, town and village, shall be paid into the county treasury and fifty percent of such tax so collected may be placed to the credit of the incorporated city, town or village in which it was collected, and that the same may be paid out to such incorporated city, town or village, by the majority action of the county commission when the verified claim is made. Such claim may be paid upon warrants of the county commission in favor of the treasurer or other designated officer of such incorporated city, town or village, to be used and applied exclusively in the improvement and repair of established public roads, streets, and bridges within the corporate limits of such incorporated city, town or village; and the county highway engineer shall keep a separate voucher account for each of such incorporated cities, towns and villages. If any money remains in the county treasury for two years from the date it was paid into the treasury without being paid out, or appropriated for current incomplete contracts, such money shall be transferred from the city, town or village road fund to the special road and bridge fund and such city, town or village shall lose the benefit thereof. The remaining sum of all such tax funds whether collected upon property within a special road district or within the limits of any incorporated city, town or village shall be retained and used by the county commission in the improvement of roads and bridges; provided, that refunds authorized under the provisions of this section shall not be made to any city having a population of more than three hundred and fifty thousand inhabitants.