Robust solutions to the pollution-routing problem with demand and travel time uncertainty

Freight transportation activities could potentially lead to detrimental effects on the natural and built environments and pose health risks. The importance of the present study is to consider demand and travel time uncertainty in green transport planning by proposing several robust optimization techniques; soft worst case, hard worst case and chance constraints. These techniques provide the most reliable solutions with very limited increase in the objective function related to fuel consumption and CO2-equivalent emissions