Hiking is among the most popular outdoor activities. In this paper, we introduce the hiking tourist problem (HTP) to support hikers in their trip planning to attractive hiking spots in a certain region. In the HTP, a set of hikes out of a larger set of potential hikes is selected and the mode of transport between the hiking locations is determined. The considered constraints involve a minimum and a maximum number of travel days, a maximum total cumulative elevation gain of all selected hikes and a maximum number of hikes. Two objectives are optimized concurrently: the total attractiveness of the travel plan is maximized and its total emissions are minimized. Several families of valid inequalities are discussed and a bi-objective branch-and-bound algorithm is tailored to solve the proposed problem. In a computational study on realistic instances for different regions in France, the impact of the proposed valid inequalities is analyzed and the trade-off between attractiveness and emissions is discussed.
Forschungs-