Fleet planning for environmentally conscious instant delivery

The continuous growth of e-commerce and urban populations has intensified the demand for instant delivery services, increasing the complexity of urban logistics. At the same time, growing environmental concerns and stricter sustainability targets require innovative fleet planning approaches that balance economic performance, service quality, and environmental impact. This paper presents a mixed-integer linear optimization framework to support strategic and tactical decision-making in fleet planning for instant delivery services with heterogeneous orders. The model optimizes fleet size and composition across multiple vehicle types and ownership structures-including company-owned and crowdsourced options-while considering cost and environmental objectives as well as service-level concerns. The approach is validated through a real-world case study of an instant delivery company operating in London, UK. Results show that a hybrid fleet configuration combining a dedicated core fleet with flexible crowdsourced capacity achieves a superior balance between cost efficiency, service quality, and environmental performance compared to conventional strategies. Moreover, integrating low-emission vehicles and micromobility options further enhances sustainability, while overall costs remain stable under realistic parameter variations. These findings offer actionable insights for logistics providers and support the development of more efficient, flexible, and environmentally sustainable last-mile delivery systems.