Applied Science & Engineering Technology

This paper combined a transportation allocation benchmark with a multi-depot capacitated routing MILP to plan last-mile deliveries in an illustrative Mumbai case. Solved to proven optimality, the model cut daily cost by 20.4% and distance by 14.5% relative to a nearest-depot, nearest-neighbour baseline, with most of the gain coming from running one van fewer. The transportation model reproduced the optimal depot allocation almost exactly but could not see the fleet saving, which shows why allocation and routing should be optimised together. Scenario testing showed that the plan is robust to cost-rate changes but responds sharply to capacity and demand through the minimum fleet size. Because the data are synthetic, the contribution is a transparent, reproducible method and a set of managerial insights to be tested on real data, not an empirical finding about Mumbai's delivery sector.

[1]     J. Olsson, D. Hellström, and H. Pålsson, "Framework of last mile logistics research: A systematic review of the literature," Sustainability, vol. 11, no. 24, Art. no. 7131, 2019, doi: 10.3390/su11247131. [2]     N. Boysen, S. Fedtke, and S. Schwerdfeger, "Last-mile delivery concepts: A survey from an operational research perspective," OR Spectrum, vol. 43, no. 1, pp. 1–58, 2021, doi: 10.1007/s00291-020-00607-8. [3]     M. Savelsbergh and T. Van Woensel, "50th anniversary invited article—City logistics: Challenges and opportunities," Transportation Science, vol. 50, no. 2, pp. 579–590, 2016, doi: 10.1287/trsc.2016.0675. [4]     L. Ranieri, S. Digiesi, B. Silvestri, and M. Roccotelli, "A review of last mile logistics innovations in an externalities cost reduction vision," Sustainability, vol. 10, no. 3, Art. no. 782, 2018, doi: 10.3390/su10030782. [5]     R. Mangiaracina, A. Perego, A. Seghezzi, and A. Tumino, "Innovative solutions to increase last-mile delivery efficiency in B2C e-commerce: A literature review," International Journal of Physical Distribution & Logistics Management, vol. 49, no. 9, pp. 901–920, 2019, doi: 10.1108/IJPDLM-02-2019-0048. [6]     G. Laporte, "Fifty years of vehicle routing," Transportation Science, vol. 43, no. 4, pp. 408–416, 2009, doi: 10.1287/trsc.1090.0301. [7]     P. Toth and D. Vigo, Eds., Vehicle Routing: Problems, Methods, and Applications, 2nd ed. Philadelphia, PA, USA: SIAM, 2014, doi: 10.1137/1.9781611973594. [8]     F. L. Hitchcock, "The distribution of a product from several sources to numerous localities," Journal of Mathematics and Physics, vol. 20, no. 1–4, pp. 224–230, 1941, doi: 10.1002/sapm1941201224. [9]     F. S. Hillier and G. J. Lieberman, Introduction to Operations Research, 11th ed. New York, NY, USA: McGraw-Hill Education, 2021. [10]    G. B. Dantzig and J. H. Ramser, "The truck dispatching problem," Management Science, vol. 6, no. 1, pp. 80–91, 1959, doi: 10.1287/mnsc.6.1.80.