Metaheuristicsforthewastecollectionvehicleroutingproblemwithtime windows, driverrestperiodandmultipledisposalfacilities

In thisproblemthereisasetofwastedisposalfacilities,asetofcustomersatwhichwasteiscollected and anunlimitednumberofhomogeneousvehiclesbasedatasingledepot.Emptyvehiclesleavethe depot andcollectwastefromcustomers,emptyingthemselvesatthewastedisposalfacilitiesasand when necessary.Vehiclesreturntothedepotempty.Wetakeintoconsiderationtimewindows associatedwithcustomers,disposalfacilitiesandthedepot.Wealsohaveadriverrestperiod.The problemissolvedheuristically.Aneighboursetisdefinedforeachcustomerasthesetofcustomers that areclose,butwithcompatibletimewindows.Aprocedurethatattemptstofullyutiliseavehicleis used toobtainaninitialsolution,withthisinitialsolutionbeingimprovedusinganinterchange procedure.Wepresenttwometaheuristicalgorithmsusingtabusearchandvariableneighbourhood search thatarebasedaroundtheneighboursets.Wealsopresentametaheuristicbasedonvariable neighbourhoodtabusearch,wherethevariableneighbourhoodissearchedviatabusearch. Computationalresultsarepresentedforpubliclyavailablewastecollectionproblemsinvolvingupto 2092 customersand19wastedisposalfacilities,whichindicatethatouralgorithmsproducebetter quality solutionsthanpreviousworkpresentedintheliterature.