Alteration of bus routes in large-scale networks

Route assignment and scheduling of buses are critical in network utilization and modification of bus routes should seek more efficient methods for operation. Ineffective operations would increase the average travel time and therefore decrease the level of service which yields increase in social cost. This paper presents an alteration method for increasing the efficiency of bus networks considering the shortening of routes without changing the vehicle headway. Istanbul city has major congestion, environmental, and safety problems. A need exists to develop a practical methodology to modify the bus routes along with efficiency considerations for more reliable and better quality of service. Besides long and inefficient lanes, there are significant kilometers of routes overlapping on existing bus network of Istanbul. The total savings, through reducing parallel capacities along Metrobus (BRT) and Tramway, are determined for both of the operator and user perspective. It is shown that, improvements in terms of service quality for passengers and efficiency for operators can be achieved simultaneously by changing route alternatives. The results shows that by shortening most of the lines analyzed with all the measures proposed, considerable amount of bus kilometers per day can be saved. In addition, by reducing headways in low occupied sections and by accelerating bus lines the average speed of buses are increased which leads to travel time and accordingly economic savings. The alteration of the bus routes has also impacts on other modes, such as privately operated buses, are also investigated. In conclusion, the results are interpreted for the Istanbul metropolitan area in the light of quality of the service measures.