5.1.2 Formulation based on flow -- 5.1.3 Formulation based on two commodities -- 5.2 Inventory-routing problem -- 5.2.1 Formal problem definition -- 5.2.2 Exponential-size formulation -- 5.2.3 Polynomial-size formulation -- 5.3 Production-routing problem -- 5.3.1 Formal problem definition -- 5.3.2 Mathematical modelling -- References and further reading -- 6: Green freight distribution -- 6.1 Introduction -- 6.1.1 Emissions and pollution -- 6.1.2 Noise and vibration -- 6.1.3 Land and resource consumption -- 6.1.4 Toxic effects -- 6.2 Mitigating measures -- 6.3 Quantifying externalities -- 6.3.1 Fuel consumption models -- 6.3.1.1 Emission factor model -- 6.3.1.2 Average speed model -- 6.3.1.3 Instantaneous emissions model -- 6.4 Green freight distribution planning -- 6.4.1 Pollution-routing problems -- 6.4.1.1 Fleet mix, fuel consumption and emissions -- 6.4.2 Speed optimisation on fixed routes -- 6.5 Practical application: Speed optimisation in maritime shipping -- References and further reading -- 7: Collaboration in freight distribution -- 7.1 Cooperative game theory -- 7.1.1 Core -- 7.1.2 Shapley value -- 7.1.3 Banzhaf index -- 7.2 Practical application: Cooperation among freight carriers -- References and further reading -- 8: Methodology -- 8.1 General-purpose solvers -- 8.2 Exact solution techniques -- 8.2.1 Benders decomposition -- 8.2.2 Application to uncapacitated network design -- 8.2.2.1 Benders decomposition using an aggregated formulation -- 8.2.2.2 Benders decomposition using a stronger formulation -- 8.2.3 Lagrangean relaxation -- 8.2.4 Application to uncapacitated network design -- 8.2.4.1 Relaxing the arc constraints -- 8.2.4.2 Relaxing the flow constraints -- 8.3 Heuristic solution techniques -- 8.3.1 Constructive heuristics -- 8.3.2 Neighbourhoods -- 8.3.3 Evaluation function -- 8.3.4 Local search -- 8.3.5 Metaheuristics