Nowadays environmental, social, and political pressures to limit the impacts linked to CO2 emissions are rapidly increasing. This paper aim at the solution of a new class of A routing problem: the sustainable routing problem, where the objective, unlike the classical approaches, is the CO2 emission minimisation. The amount of CO2 emitted by a vehicle depends on different factors. If the problem is analysed from the driver's point of view, these factors can be divided into 'internal', i.e., directly related to him/her (i.e., driving style, acceleration, average speed, route knowledge, etc.), and into 'external', i.e., depending on the environment in which the trip is made (i.e., traffic congestion, speed limits, vehicle type, etc.). Firstly the paper, starting from Fonseca et al. (2011) study, proposes a CO2 emission estimation as function of the different internal/external factors. Secondly, the authors formalise a sustainable routing model, validating it through a case study as well as a parametric analysis. The results suggest that, contrary to the classical vehicle routing problem, the proposed model allows a larger reduction of CO2 emission versus the increasing time and distance, suggesting interesting potentials in the environmental preservation.
