This paper studies the double traveling salesman problem with two stacks. A number of requests have to be served where each request consists in the pickup and delivery of an item. All the pickup operations have to be performed before any delivery can take place. A single vehicle is available that starts from a depot, performs all the pickup operations and returns to the depot. Then, it performs...

In pickup and delivery problems vehicles have to transport loads from origins to destinations without transshipment at intermediate locations In this paper we discuss several characteristics that distinguish them from standard vehicle routing problems and present a survey of the problem types and solution methods found in

The single vehicle routing problem with multiple routes is a variant of the vehicle routing problem where the vehicle can be dispatched to several routes during its workday to serve a number of customers. In this paper we propose a goal programming model for multi-objective single vehicle routing problem with time windows and multiple routes. To solve the model, we present a heuristic method wh...

This paper deals with the Vehicle Routing Problem with Simultaneous Pickup and Delivery (VRPSPD). A procedure based on the Iterated Local Search (ILS) metaheuristic that uses the Variable Neighborhood Descent (VND) method for performing the local search is proposed. According to literature, the most successful algorithms for the VRPSPD are pure or hybrid versions of the Tabu Search metaheuristi...

We consider a rich tanker trailer routing problem with stochastic transit times for chemicals and liquid bulk orders. A typical route of the tanker trailer comprises of sourcing a cleaned and prepped trailer from a pre-wash location, pickup and delivery of chemical orders, cleaning the tanker trailer at a post-wash location after order delivery and prepping for the next order. Unlike traditiona...

The problem of designing a set of routes with minimum cost to serve a collection of customers with a fleet of vehicles is a fundamental challenge, when the number of customers to be dropped or picked up is not known during the planning horizon. The purpose of this paper is to develop a vehicle routing Problem (VRP) model that addresses stochastic simultaneous pickup and delivery in the urban pu...

Communities of autonomous units are being developed for formal specification and semantic analysis of systems of interacting and mobile components. The autonomous units of a community are rulebased, self-controlled, goal-driven, and operate and move in a common environment. We employ communities of autonomous units to model the dynamic pickup and delivery problem with the general idea to demons...

Optimization of on-demand transportation systems and ride-sharing services involves solving a class of complex vehicle routing problems with pickup and delivery with time windows (VRPPDTW). This paper first proposes a new time-discretized multi-commodity network flow model for the VRPPDTW based on the integration of vehicles’ carrying states within space–time transportation networks, so as to a...