A navigation application was developed and tested in Ahmedabad to promote the use of public transportation through the provisioning of auto rickshaws as feeder transportation services. The app provides suitable mode and route for seamless access, not only by integrating information on multiple modes but also a booking and payment function. Based on a questionnaire survey administered to explore the possibility of a modal shift from private to public transportation and its effect on reducing carbon dioxide emissions, a mode choice model with a discrete choice framework was developed. It was found that the booking and payment function only slightly enhanced the probability of selecting public transportation as accessed by feeder transportation. However, the model with this function was applied to the actual behavioral data obtained from the field experiment, and a reduction in carbon dioxide emissions was not achieved through the booking and payment function. This is because the data from the field experiment indicated a high level of convenience in the use of passenger cars, thus it did not lead to a change in the choice of travel modes.