Through this, the researchers found that one-third of DiDi trips potentially substitute for public transit, with a ride-sourcing trip considered potentially a substitute for public transit if the trip can be effectively served by public transit.
The time of the day and the location matter as well. The researchers found that the substitution rate is higher during the daytime (8 a.m. to 6 p.m.) and more significant in the city center. Also, substitution trips appear more in the areas with higher building density and land use mixture. During the day, around 40 percent of DiDi trips have the potential to substitute for public transit, but the researchers found that this substitution rate decreases as the supply of transit decreases.
The researchers also found that the substitution effect is more significant in more developed areas covered by subway lines, while peripheral and suburban areas were dominated by complementary trips. However, they also note that house prices were positively correlated with the substitution rate, highlighting the importance of public transit to less-wealthy populations.