in the period between 1940 and 1950 As the city grew, it expanded out into the suburbs, driven in large part by the opening in 1946 of the landmark Avenida Brasil (Brazil Avenue), as well as sanitation and electrification works.

with the opening of the Avenue, the word 'suburb' began to take on a new meaning, ceasing to refer to all surrounding regions, and instead beginning to particularly and exclusively denominate districts located along the railways to the north and west of the city.

this is period that first saw the clear zoning and denomination of the city in the familiar terms zona norte, zona oeste, zona central, and zona sul .