The City Council shall refer every proposed resolution, order or ordinance for the regulation of traffic, or any amendment thereto, to the Commission for its study and report. No final vote shall be taken by the City Council on any such resolution, order or ordinance until the Commission has submitted its report with recommendations, in writing, or until 20 days shall have elapsed after reference to the Commission without the filing of such report. Such reports and recommendations shall be advisory only, and shall not have the force and effect of law.