At least thirty days prior to the beginning of construction work in any county affected by the provisions of this subheading, the Mayor and City Council of Baltimore shall file in the office of the County Commissioners of such county one or more maps showing the existing public roads and highways traversing the property acquired or to be acquired under this subheading, which are to be closed, altered, diverted or relocated, in whole or in part, or the grades thereof changed; and also to show all roads or parts of roads which the Mayor and City Council of Baltimore proposes to construct in substitution for, or to take the place of, any such roads so closed, obstructed, altered or changed. P.L.L., 1949, §665 1969, §25-38 1931, ch. 521