The vehicle routing problem is used to find an optimal solution to find the best route for the fleet of vehicle in organisation by determining the vehicle capacity, number of customers, time taken, distance form depot location to customer location, total demand etc. are taken into consideration. The ultimate aim of vehicle route optimisation is to reduce the cost of the transport, and also increase the efficiency of the transportation system of the organisation by reducing the travel time or distance. (Clarke and Wright, 1964, Prins, 2004; Cordeau et al, 2007a; Perboli et al, 2008).
A CVRP added with time constrain becomes a vehicle routing problem with time windows (CVRPTW). The customers have to be served within the given time window. It is defined by the number of vehicle available and their capacity, customers, demand and time window There are many algorithms available, but none of them were proven to be an optimal solution for the CVRPTW.
Akeb, Bouchakhchoukha and Hifi, 2014 proposed a three-stage procedure for CVRPTW. 1) A grouping stage in which the set of customers are branched into
Disjoint groups, 2) a construction stage, that provides beneficial tour in each group, 3) to improve the quality of the results derived from the earlier stage, a local search stage is applied.