Economic Viability of Bus Bridging Reserves for Fast Response to Unplanned Passenger Rail Disruption

A new approach explores the economic viability of dedicated bus reserves purely for bus bridging purposes. The approach estimates fleet costs and user benefits of reduced delay by improving the response to unplanned rail disruption. The feasibility of dedicated bus reserves has not been considered in previous research. Sourcing buses for bus bridging purposes is problematic during weekday peak periods, which coincide with the highest demand for rail travel. At all other times spare buses are available. Consequently, a dedicated bus reserve would exist mainly to provide bus bridging in the peak. Results suggest that a dedicated bus bridging reserve can be economically viable. Of 18 corridors studied, a dedicated reserve was feasible for 78 %. Economically viable corridors have a benefit cost ratio ranging between 1.5 and 9.7 (average, 4.5). Reserves were not feasible where existing rail demand, disruption likelihood, or both were low. Sensitivity tests explored viability with more conservative assumptions. In each test, the dedicated bus reserve in most corridors remained economically viable. The research suggests that a dedicated bus reserve should be considered by rail operators worldwide because of strong net economic benefits. However, reserves are a net cost (with no income), so investment must be based on economic, not financial, benefits. This aspect suggests that government authorities, rather than commercial operators, may find a dedicated reserve more feasible. This approach illustrates where reserves might best be allocated to maximize investment returns.