The board of directors of any township may expend not more than one-fourth of the revenue accruing to it from taxes levied upon property situated within the limits of any city, town or village within the township for the repair and improvement of existing roads, streets and bridges within the city, town, or village from which such moneys accrued, and for the purpose of constructing and maintaining macadam, gravel, rock or paved roads or streets within the corporate limits of any city within the township in conformity with the established grade of the roads and streets of such city; except that no part of the revenue of any township shall be expended outside of the county in which the township is located.