An Improved Simulated Annealing Algorithm for Fleet Size and Mix Vehicle Routing Problem with Time Windows

The fleet size and mix vehicle routing problem with time windows (FSMVRPTW) is an important extended type of vehicle routing problem, and it has been proved to be a NP-hard problem in combinatorial optimization, which is difficult or impossible to obtain optimal solutions in large-scale cases. A four-step improved simulated annealing algorithm is proposed, which obtains a good initial solution through the construction of the first three steps and introduces four local search operators to iterate in the fourth step. To evaluate its performance, we test it with Solomon's VRPTW benchmark problems. The computational results demonstrate that the high -quality solutions can be obtained by using the new algorithm within an accepted computational time.