Why did the West Zone of Rio de Janeiro become more accessible in the late 20th century?

The West Zone of Rio de Janeiro became significantly more accessible in the late 20th century primarily due to the expansion of the city's highway system and an increased reliance on automobiles.1

A key development in this transformation was the opening of the Yellow Line Highway in the late 1990s. By running west from Governador Island and utilizing tunnels to pierce the mountainous terrain that had previously acted as a barrier, this infrastructure project opened up the large inland area beyond Tijuca. These improvements in the road network facilitated urban growth, allowing the population to expand further northwest toward areas like Santa Cruz and Campo Grande, as well as along the coast toward Guaratiba and the port at Sepetiba.2