WHEN DO PARCEL LOCKERS PAY? A COST-TO-SERVE MILP FOR TWO-WHEELER LAST-MILE DELIVERY IN MUMBAI
Design/methodology/approach – We reviewed 75 journal articles published from 2015 to 2025 using OpenAlex and the required “operations AND research” terms, then checked 1,086 records for research gaps using keyword-based searches. We also developed a mixed-integer linear programming model (MILP) that extends the capacitated vehicle routing problem by including locker assignments, expected failed-delivery costs and penalties for deferring deliveries. The model was solved with CBC using Mumbai delivery instances and road distances from OpenStreetMap.
Findings – Drones feature in 31% of the screened articles, but failed deliveries appear in just 1.1% and cost per parcel in only 0.5% of the broader set of records. Compared with nearest-neighbour routing, exact routing lowered daily costs by 4.9–8.2%. Locker diversion contributed a further saving of up to 1.9% and was chosen only when a failed attempt cost at least INR 90 or the customer incentive was no more than INR 5. Driver wages had the greatest effect on cost per parcel.
Originality – The study connects a bibliometric review of research gaps with a reproducible MILP, translating routing choices into unit economics for a two-wheeler delivery fleet in an emerging-market city.
Practical implications – In a congested city where wages are relatively low, lockers make financial sense mainly when the full cost of a failed delivery is high, not simply because they improve route efficiency.
Keywords: last-mile delivery; vehicle routing; mixed-integer linear programming; parcel lockers; failed deliveries; bibliometric analysis
Kundu, P., Vazir, R., Singhi, N., Sunely, A. & Varia, K. (2026). When Do Parcel Lockers Pay? A Cost-To-Serve MILP For Two-Wheeler Last-Mile Delivery in Mumbai. International Journal of Science, Strategic Management and Technology, 02(10), 1-9. https://doi.org/10.55041/ijsmt.v2i10.074
Kundu, Pritish, et al.. "When Do Parcel Lockers Pay? A Cost-To-Serve MILP For Two-Wheeler Last-Mile Delivery in Mumbai." International Journal of Science, Strategic Management and Technology, vol. 02, no. 10, 2026, pp. 1-9. doi:https://doi.org/10.55041/ijsmt.v2i10.074.
Kundu, Pritish,Rohan Vazir,Neev Singhi,Ali Sunely, and Karan Varia. "When Do Parcel Lockers Pay? A Cost-To-Serve MILP For Two-Wheeler Last-Mile Delivery in Mumbai." International Journal of Science, Strategic Management and Technology 02, no. 10 (2026): 1-9. https://doi.org/https://doi.org/10.55041/ijsmt.v2i10.074.
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