Human mobility in large cities is a complex dynamical system with high density of population, many transport modes to compete for limited available space and many operators that try to efficiently manage different parts of this system. New emerging modes of transportation such as ride-sourcing (known as Transportation Network Companies – TNCs) and on-demand services create additional opportunities, but also more complexity. It is imperative to understand how TNCs' operations can interfere in traffic conditions while replacing other transportation modes to seek improvements in urban mobility. Moreover, the matching process shall have a place and thus the impact of passengers' behavior too, in a ridesplitting scenario. Therefore, this paper aims to investigate the effect of expanding fleet sizes for TNCs, passengers with different willingness to share, and operational strategies over congestion conditions under a sustainable perspective. This investigation considered a simulated urban network with real demand data from taxis in a megacity and incorporated traffic conditions through a Macroscopic Fundamental Diagram (MFD). Results show that sharing (allowing passengers to share their ride and have many passengers willing to do so) by itself is not capable of decreasing VKT if there is no control to the fleet size. On the other hand, sharing decreases the number of vehicles needed to provide high coverage and service times. To reduce emissions (by reducing VKT), TNCs should change their modus operandi; in a way to avoid that their fleet cruises without a defined trip (passenger with origin and destination).