The solution of routing problems with soft time windows has valuable practical applications. Soft time window solutions are needed when: (a) the number of routes needed for hard time windows exceeds the number of available vehicles, (b) a study of cost-service tradeoffs is required, or (c) the dispatcher has qualitative information regarding the relative importance of hard time-window constrain...

The competitive vehicle routing problem is one of the important issues in transportation area. In this paper a new method for competitive VRP with time windows and stochastic demand is introduced. In the presented method a three time bounds are given and the probability of arrival time between each time bound is assumed to be uniform. The demands of each customer are different in each time wind...

Vehicle routing problems with time windows are NP-hard problems. Additional difficulties are introduced by dynamic client requests and crisis situations. One of the techniques used in order to solve such problems are evolutionary algorithms. In this paper a coevolutionary algorithm with spatial population structure is presented. The system is verified with the use of dynamic vehicle routing pro...

this paper discusses the multi-depot vehicle routing problem of heterogeneous fleet of vehicles with time windows for perishable commodities. the objective of the problem is to minimize the total time required for servicing all customers that is equivalent to the total cost. commodities are delivered to the customers with defined time windows by a fleet of heterogeneous vehicles, which have lim...

Transportation sector generates a considerable part of each nation's gross domestic product and considered among the largest consumers of oil products in the world. This paper proposes a heuristic method for the vehicle routing problem with hard time windows while incorporating the costs of fuel, driver, and vehicle. The proposed heuristic uses a novel speed optimization algorithm to reach its ...

this paper presents a multi-criteria vehicle routing problem with soft time windows (vrpstw) to mini-mize fleet cost, routes cost, and violation of soft time windows penalty. in this case, the fleet is heterogene-ous. the vrpstw consists of a number of constraints in which vehicles are allowed to serve customers out of the desirable time window by a penalty. it is assumed that this relaxation a...

Vehicle Routing Problem with Time windows (VRPTW) is an example of scheduling in constrained environment. It is a well known NP hard combinatorial scheduling optimization problem in which minimum number of routes have to be determined to serve all the customers within their specified time windows. So far different analytic and heuristic approaches have been tried to solve such problems. In this...

 We consider a pickup and delivery vehicle routing problem (PDP) commonly find in real-world logistics operations. The problem includes a set of practical complications that have received little attention in the vehicle routing literature. In this problem, there are multiple vehicle types available to cover a set of transportation orders, each of which has pickup time windows and delivery time...