Simulating Dynamic Vehicle Routing Problems With Athos

Abstract

Complex routing problems, such as vehicle routing problems with additional constraints, are both hard to solve and hard to express in a form that is accessible to the human expert and at the same time processible by a computer system that is supposed to produce a solution of sufficient quality. The formulation must be formal enough to avoid ambiguities and also comprehensible enough to be created, discussed and shared by domain experts. In this paper, we present the domain specific language Athos in which complex routing problems can be expressed in a computationally independent, human-readable form. Athos is then transformed into code that can be run in an adequate target platform. Suitable methods for solving problems are available and applied to the given problem. We present a case study in which we use a genetic algorithm to solve instances of a vehicle routing problem with time windows and demonstrate the end to end process to produce a solution in the Athos environment. Moreover, we show how the Athos system goes beyond optimisation of static routes and can be used as a tool to simulate the impact of traffic and congestion on the tours. We call this extended problem a dynamic vehicle routing problem with time windows.