A matheuristic for the truck and trailer routing problem

3 COPA, Department of Industrial Engineering, Universidad de los Andes, Bogota, Colombia {amedagli, nvelasco}@uniandes.edu.co In the truck and trailer problem (TTRP), raised for instance by milk collection in rural areas, a heterogeneous fleet composed of mt trucks and mr trailers (mr < mt) serves a set of customers N = {1, 2, ..., n} from a main depot, denoted as node 0. Each customer i ∈N has a non-negative demand qi > 0; the capacities of the trucks and the trailers are Qt and Qr, respectively; and the distance cij between any two nodes i, j ∈N ∪ {0} is known. Some customers with limited maneuvering space or accessible through narrow roads must be served only by a truck; while other customers can be visited either by a truck or by a complete vehicle, e.g., a truck pulling a trailer. These access constraints partition the customers into two subsets : the subset of truck customers Nt accessible only by truck, and the subset of vehicle customers Nv, accessible either by a truck or by a complete vehicle.