The special assessment taxes levied for the payment of funding bonds shall be independent of and distinct from any other levies authorized by this part and shall be levied, collected and enforced by the proper officers of the several counties within the district, in behalf of the joint highway district and in the same manner and by the same persons and at the same time and with the same penalties and interest as are taxes for county purposes, and all laws applicable to the levy, collection and enforcement of taxes for county purposes are hereby made applicable to these special assessment taxes where such laws are not in conflict with the provisions of this part except that such

special assessment taxes shall be levied and collected upon land only, exclusive of the improvements thereon.