The county commission of any county in this state may transfer to the road fund of the county any surplus of the general funds of the county in the county treasury or any part of such surplus whenever, in the judgment of such commission, it will promote the interest of the county to make such transfer. Any surplus of the general fund so transferred shall be used only for the working of the public roads or the building of bridges or otherwise improving the roads of such counties.
Ala. Code § 23-1-83 (1975)