An Optimization-based Approach for Designing Urban Low Emission Zones

In the last decades, the continuous concentric development of big cities has driven an increase in the number of trips performed by private vehicles to/from the city centers, resulting not only in an increase in congestion but also acting as a major contributor to the issues related to traffic pollution.In this connection, although several strategies have been investigated and implemented, modal shifting from private vehicles to public transport still remains the most effective. In this connection, to enforce the usage of sustainable transport modes, the concept of Low Emission Zones (LEZs) has been implemented in many cities in order to restrict the admission of the most polluting vehicles, allowing only the circulation of more sustainable transport modes.Nevertheless, LEZ design is often based on a trial and error approach relying on the experience of the designer and, often, strongly dependent on the particular city under analysis.In order to support the generalization of the LEZ design problem, this paper explores the potentialities of an optimization-based approach aiming at determining the biggest area to include in the LEZ while, at the same time, minimizing the increase of users’ generalized costs and saturation over links. To test the capabilities of the proposed approach, a case study is also analyzed.