Optimal bus reassignment considering in-vehicle overcrowding

• Severe weather conditions can cause operational challenges such as in-vehicle overcrowding and delays. • Reassigning buses from low-demand to overcrowded lines is a cost-effective solution to in-vehicle overcrowding issues. • Bus reassignment enables operators to efficiently utilize their existing capacity under disrupted conditions. • Our approach does not require additional drivers/vehicles to be reserved in the depots. Public transport services are often designed to meet travel demand under regular situations. However, severe weather conditions (e.g., heavy rainfall, snow, thunderstorms, etc.) can adversely impact the service operation, leading to problems such as in-vehicle overcrowding, delays, and trip cancellations. In this study, we propose a novel approach to address in-vehicle overcrowding issues during weather disruptions. In this approach, we dynamically reassign buses from low-demand trips to lines where the expected demand exceeds the capacity threshold of the in-service buses. This way, the existing capacity is utilized more efficiently without requiring additional vehicles or drivers. Considering the shortage of bus drivers in Europe, as well as in the Netherlands, this is a more efficient solution than other alternatives such as deploying additional buses from the depot. Experiments were conducted on a bus network in Enschede in the Netherlands. The results showed that in several disrupted situations, we can reassign bus trips to overcome overcrowding issues without significant negative impacts on the operation or passengers. However, the approach entails a trade-off between passengers of a canceled trip and an overcrowded trip. Some passengers must wait for the next bus or use other means of transport as a consequence of bus reassignment.