Optimizing Public Transit: A Critical Analysis of Increased Bus Frequency and its Effects on Traffic Dynamics

Designing public transit systems to be more attractive is essential for fostering sustainable mobility in order to achieve a modal shift towards a higher share of public transit users. The public transit supply has been identified as a key determinant influencing individuals’ mode choice, with inadequate service provision often discouraging potential users from opting for public transit. One proposed approach in literature to enhance the attractiveness of public transit bus systems is to increase service frequency. However, an accurate analysis of the network-wide impacts of such a strategy on traffic dynamics should not be neglected. In our study, we addressed this issue by focusing on the city of Burgdorf, Germany, as a case study. We utilized SUMO simulation to replicate the current traffic demand and the existing public transit bus system. Subsequently, we conducted a sensitivity analysis in which we adjusted the frequency of all operating bus lines in Burgdorf. Our analysis evaluated KPI’s such as mean speed and the number of halting vehicles, along with the macroscopic fundamental diagram to assess network capacity. The results indicated that even with all bus lines in Burgdorf operating at a 10-minute frequency, the network’s capacity was only slightly affected. The overall mean speed of motorized individual traffic increased minimally. Traffic conditions were negatively affected if bus headways are reduced to 5 minutes, as this led to a considerable reduction of 5 % in capacity and of 15.5 % in mean speed.