The Teodoro Moscoso Bridge in San Juan is a 2.25 km long engineering work built in the 1990s over the San José Lagoon that connects Jesús T. Piñero and Román Baldorioty de Castro Avenues. Almost twenty years after its completion, we were appointed to significantly reduce its electrical energy consumption and modernize its traffic lighting systems. We conducted an Energy Audit in which we identified and thoroughly analyzed conservation measures. By taking physical measurements and performing various software simulations, we specified the solution that improved lighting levels and visibility on the bridge roadways while reducing energy consumption.