On November 15, 2014, while crossing Lieja street and Chapultepec avenue in the Cuauhtémoc borough, a bike rider collided with a public transport bus and died only a few minutes later on the crossroads. This project seeks to elaborate open and collaborative practices among strategic actors in order to ensure the safety of the users of a dangerous crossroads through a practical intervention on the targeted site. In a city where live and work 14 million people, safe and sustainable mobility is a major issue. Accidents between cars, buses, pedestrians and/or bike riders are common, especially on big crossroads where constructions are in progress. How do we enable the users to coexist safely?