Energy costs related to traffic on urban road networks - Future perspectives of sustainable mobility

The large use of private motorized vehicles in the city has significant negative impacts for the community, in terms of accidents, pollution, energy consumption, social costs. In recent years, strategies have been elaborated to limit these impacts. With specific reference to energy consumption, there are measures aimed at making engines more efficient or at modifying the vehicle fleet (electric, hybrid, motorless vehicles). The above impacts are considered interesting, in terms of quantitative indicators, in the transport planning context. One of the relevant phases of a Plan process is the traffic simulation on networks which leads to the estimation of vehicle flows on road sections and some derived attributes, such as average speed of outflow and degree of saturation that allow to evaluate the service levels. Among the most significant indicators for planners and decision makers, the measurement of energy consumption is also interesting both on individual links and on the network. The paper proposes a review of mathematical/experimental models useful for making consumption assessments, taken from the specialized literature. An original model is proposed, developed as an envelope of literature models, capable of covering a wide range of traffic conditions. Finally, the results of an application related to traffic simulation of an Italian urban road network and the comparative estimation of energy consumption for different scenarios are illustrated.