Analysis of Urban Service Reliability and Its Effect on Traffic Congestion

Urban service reliability represents the level of service in the aspects of travel time, arrival time, and seat availability from the user's perspective. Service reliability focuses on the demand and supply sides of transportation systems. The supply side consists of services provided by the operator, hence it affects the travel time. Meanwhile, demand side focuses on passenger side which includes passenger behavior and experience. The main objective of this research is to analyze urban service reliability and its impact on traffic congestion. Several main factors impacting the service reliability were evaluated using system dynamics simulation model. It has been used to test and evaluate the alternatives of future strategies to increase service reliability and to mitigate the traffic congestion. Simulation results show that service reliability is influenced by two factors, those are passenger's perception and public transportation agency performance. Travel time and waiting time are two important factors of passenger's perception. Meanwhile, some factors such as the ratio of public transportation supply and demand as well as the service effectiveness are the important factors of public transportation agency performance. Based on the existing condition, service reliability in public transportation sector is around 44%. This service reliability is projected could be increased to 76% by conducting a strategy such as the addition of public transportation facilities, which aims to decrease the passenger's waiting time and to increase the ratio of public transportation supply and demand. All of these efforts will increase the passenger's perception and public transportation agency performance. With the increased in service reliability, traffic congestion is projected could be reduced to 40% - 75%.