It shall be unlawful for any person, firm or corporation to violate any rule, regulation or law which has heretofore been adopted or promulgated or which may hereafter be adopted or promulgated by the county commission of any county, under the authority conferred by law, relating to the use, control, care, operation or maintenance of the public roads, bridges or ferries of said county; and any person, firm or corporation violating the same shall be deemed guilty of a misdemeanor and, upon conviction, shall be fined not more than $500.00 and may also be sentenced to hard labor for the county for not more than six months. Each violation shall constitute a separate offense.