Reducing greenhouse gas emissions of a heterogeneous vehicle fleet

Recent research on the vehicle routing problem attempts to integrate so-called green aspects into classical planning models. The minimization of transport-related emissions (especially CO2) instead of driving distances is an important integration approach. Within this paper, we propose an approach which is focusing on the reduction of CO2 emissions caused by transportation. Based on the observation that vehicles with different maximal payload values have different payload-dependent fuel consumption characteristics, we integrate into Dantzig's classical vehicle routing model the option of choosing vehicles of different size for route fulfillment. Then, the Emission Minimization Vehicle Routing Problem with Vehicle Categories (EVRP-VC) is introduced. It aims at minimizing the fuel consumption, respectively CO2 emissions instead of the driving distances. Comprehensive computational experiments with CPLEX are conducted to evaluate the EVRP-VC. A major finding is that the quantity of fuel needed to serve a given request portfolio can be reduced tremendously by using an inhomogeneous fleet with vehicles of different size.