After the end of the Mexican revolution around the 1920s, the country urged for reconstruction. With the late and intense arrival of modern industrialization—mainly driven by the nationalization of the oil industry—the population growth in the nation boomed. This condition generated an uncontrolled migration to the capital, the old Federal District.

These internal influxes, protected under the Mexican constitutional law of 1917 ensuring decent housing for all Mexicans, incentivized since the early 40s a rapid unmanageable expansion of the urban sprawl. Ultimately, the intense populational growth has transformed the city outskirts into an architectural laboratory experimenting with different forms of moving and inhabiting the city.

Despite some changes in the demographic trends while doing this study, the suburbs built in the 70s and 80s have continued their conurbation into the political limits of the State of Mexico, extending with them the transportation/commuting routes distances between the housing settlements and the different services and industrial centers.

There are currently several systems of public transportation connecting the metropolitan region. These systems operate jointly (even using the same ticket/card) between all the different jurisdictions of the former Federal District and the State of Mexico. Each system extends differently in scale and operates its individual routes within the urban sprawl of the metropolitan region. Inside the system, one finds nodes where various—intense—layers of each system meet, thus interacting daily with tenths of millions of people.

The mixture of population flows has historically permitted the experimentation and the insertion of new building types since the early 40s. The multimodal transfer centers—CETRAM in Spanish, were introduced in the 70s. CETRAMs’ started as a complement to metro (subway) stations. However, over time they evolved into more intricate and complex centers capable of distributing millions of people into various types of public transport (RBT, subway, bus routes, taxi, Metrobus, Microbus) every day.

By selecting the CETRAM and the routes with greater ridership intensity, it is possible to track the average communing time of most users moving from the State of Mexico into the former Federal District and vice-versa. This study focuses on locating and tracking the routes resulting from the entry & exit points of the population flows coming from the State of Mexico into the Federal District daily. Following two commuting routes that split the city through a west-east cross-section, the drawing seeks to unveil and narrate the existing urban, architectural, and social contexts ordering the metropolitan scale.