This research aims to present the modeling for the implementation of the shared underground infrastructure system (joint trench model - INFRAVIAS® System) in Florianopolis Metropolitan Area in the place designated for the implementation of the public transportation system (BRT - Bus Rapid Transit) and comparative cost study with individualized deployment underground facilities. The "Joint Trench model" presented replace facilities from the street and concentrates all these in the sidewalk and bike lane, in an underground system, reducing the interventions in the street during the construction, maintenance, operation and expansion of these facilities. This underground system replace the individualized construction of natural gas pipeline, potable water, firefighting system, telephone, cable TV, data, electricity - low and medium voltage and public illumination systems and encompasses all of these facilities in an only trench in the sidewalk, inserting these in a bay made recycled plastic, designed by the concept of "fail-safe device”. The deployment of these facilities may also occur in the same period, or if necessary, at different times, thus creating flexibility to the system. The model also proposes the use of bike lane to implementation of sewage facilities, high-pressure plastic pipelines and main water, and attachment a “rain garden” system for collecting storm water, aligned with the sustainability criteria, since that collects, stores and filters water from the rains for reutilization or return clean water to the nature. The joint trench model presented, in average, cost reduction of 60% in the deployment of underground facilities. Another advantages, is concepts related to planning and urban cadastre, sustainability and resource utilization, especially with focus on safety during construction, maintenance, operation and expansion of facilities.