  Due to the practical importance of vehicle routing problems (VRP), there
exists an ever-growing body of research in algorithms and (meta)heuristics for
solving such problems. However, the diversity of VRP domains creates the
separate problem of modeling such problems -- describing the domain entities
(and, in particular, the planning decisions), the set of valid planning
decisions, and the preferences between different plans. In this paper, we
review the approaches for modeling vehicle routing problems. To make the
comparison more straightforward, we formulate several criteria for evaluating
modeling methods reflecting the practical requirements of the development of
optimization algorithms for such problems. Finally, as a result of this
comparison, we discuss several future research avenues in the field of modeling
VRP domains.
