Mathematical Optimisation of Solid Waste Collection Routes in Ibadan Metropolitan Area

This study applies mathematical optimisation to the design of solid waste collection routes in the Ibadan metropolitan area, Oyo State, South West Nigeria, one of West Africa's largest inland cities and a municipality where solid waste management represents an acute urban governance challenge. Inefficient collection routing contributes to high operational costs, incomplete spatial coverage, and the accumulation of uncollected refuse in underserved neighbourhoods, compounding the public health risks associated with inadequate sanitation infrastructure. Geographic information system data on waste generation points, road network topology, and dump site locations are obtained from the Oyo State Waste Management Authority and used to construct a directed graph representation of the collection routing problem for three wards in the Ibadan North and Ibadan South West local government areas. The travelling salesman problem formulation is applied for single-vehicle scenarios, and the vehicle routing problem with capacity constraints is formulated for fleet scenarios. The Lin-Kernighan heuristic and genetic algorithm metaheuristic are applied as solution methods, and results are compared against current operational routes to quantify improvement potential. Results demonstrate that optimised routing reduces total collection distance by 19 percent and average collection time per ward by 25 minutes relative to current practice, with equivalent service coverage. The study provides a reproducible quantitative framework for waste management professionals and municipal planners. Keywords: route optimisation, vehicle routing problem, solid waste management, genetic algorithm, Ibadan