The STM management process provides for the estimate of construction costs at various stages, from the design stage to the tendering stage, in its different services related to buses and the metro: rolling stock, installed equipment, system infrastructure, project office and engineering services. In the contexte of this public transport projects portfolio, Macogep is tasked with estimating costs, durations and the human and material resources required for various multidisciplinary projects as they are completed. Macogep has been given a complex task in that the projects are multidisciplinary and varied, and the work must be carried out without any interruption of service. Macogep’s analyses will help STM to get an objective overview of project costs.