Effects of Sunday free fare policy in São Paulo bus transportation: A case study through complex network analysis

Passenger fare policy is an important element of any transportation system and can be strategically controlled to enhance urban mobility, shift the average choice for a specific transportation mode, reduce congestion, and reduce environmental pollution. However, literature shows that the effects of these policies are not always efficient in promoting public transportation and producing relevant social benefits. Here, we investigate the effects of a fare exemption policy implemented only during Sundays in São Paulo’s bus transportation network, active since December 2023. As São Paulo is one of the largest metropolises in the world, we approach the analysis by adopting a complex network model that takes into consideration the spatial architecture of bus routes along districts. Our findings indicate a statistically significant impact of the fare exemption on both weekday and Sunday travel patterns. Evaluating travel pattern variations and considering our complex network as a spatial interaction model, we could identify hotspots where changes in daily passenger volume were more significant, finding that regions where bus transportation is not considered the main mode did not show signs of change in modal choice behavior.