Green Vehicle Routing and Scheduling Problem with Optimized Travel Speed

Among all logistics activities, transportation is presented as a major source of air pollution and other environmental concerns worldwide. Road transportation significantly increases carbon dioxide, which is a known greenhouse gas emissions of vehicles. Therefore, environmental targets are added to economic targets in the vehicle routing decision making to find the right balance between these two dimensions. Research into quantifying emission rates based on travel speeds and for different vehicle sizes, showed that based on the vehicle type and using specific emission coefficients, optimum travel speeds that minimize carbon dioxide emissions can be obtained. In this paper we propose a mixed integer programming model for the green vehicle routing and scheduling problem with time dependent travel speeds and heterogeneous fleet, in which vehicles are characterized by different capacities, costs and emissions factors. The model aims at minimizing CO2 emissions by minimizing the deviation of travel speed from optimum travel speeds.