This paper presents a new mathematical model for a periodic vehicle routing problem (PVRP) considering several
assumptions that minimizes vehicle travel costs. We incorporate four problems in periodic planning, namely a
capacitated vehicle routing problem (CVRP), a vehicle routing problem with time windows (VRPTW), a vehicle
routing problem with simultaneous pickup and delivery (VRPSPD), and a vehicle routing problem with split service
(VRPSS). As it is a unified model, we impose its computational complexity and are notable to solve such a hard
problem by any optimization software in a reasonably computational time, especially for large-sized problems. Thus,
we propose a meta-heuristic method based on particle swarm optimization (PSO). A number of instances are solved
by this proposed PSO. Finally, the related results are illustrated and discussed.