7 ) , which was based on a questionnaire launched by Le Centre d'études sur les réseaux , les transports , l'urbanisme et les constructions publiques ( CERTU ) , a scientific and research agency based in Lyon , France . The secretariat stated that once the Steering Committee and thereafter the Fourth High-level Meeting endorsed the document , it would be submitted to ECE Working Party 1 ( WP.1 ) as possible input on the development of an international standard for signs and signals under the Vienna Convention on Signs and Signals , as thus far signs and signals for active mobility were not harmonized at the international level .