This paper presents a mixed-integer linear programming model for the Internal Combustion Engine Bus Routing Problem with Time Windows for Tourists (ICE-BRPTWT), in which tourists from multiple flights are transported to hotels by a homogeneous fleet of ICE buses in a multiple-trip fashion. The model attempts to minimize total operating cost—including cost of routing, fleet deployment, and refueling—while honoring a wide variety set of constraints, such as route feasibility, capacity, time windows, and fuel consumption. Computational experiments demonstrate strong tractability only for small and moderate cases, in which CPLEX returns optimal solutions within seconds to under a minute. For larger instances, CPLEX, unfortunately, fails to determine the optimal solutions, due largely to the inherited ICE-BRPTWT complexity. This result suggests a need for efficient heuristics or metaheuristics in solving real-world ICE-BRPTWT instances, which is worth exploring in subsequent studies.

Keywords

Vehicle Routing Problem, Time Window, Mixed-Integer Linear Programming Model, Tourist Transportation, Internal Combustion Engine Buses.