A Multi-objective Approach to Long-term Interurban Multi-level Road Network Planning Bruno Santos 1 , António Antunes 2 , Eric Miller 3 Abstract This article presents a multi-objective approach to long-term interurban multi-level road network planning. In addition to the efficiency objectives dealt with in the vast majority of the literature where the subject is addressed, the approach takes into account robustness and equity objectives. For achieving the objectives, two types of action can be performed: the construction of a new road of a given level; and the upgrading of an existing road to a higher level. The approach is consistent with the planning framework of the Highway Capacity Manual, using the concept of level of service to assess traffic flow conditions. The application of the approach is illustrated for a case study involving the main road network of Poland. CE Database keywords: transportation networks; planning; highways and roads; network design; multiple objective analysis; optimization models. 1 Assistant Professor, Dep. of Civil Engineering, University of Coimbra, Polo II, 3030-290 Coimbra, Portugal 2 Professor, Dep. of Civil Engineering, University of Coimbra, Polo II, 3030-290 Coimbra, Portugal 3 Bahen-Tanenbaum Professor, Dep. of Civil Engineering, University of Toronto, 35 St. George Street, M5S 1A4, Toronto, Ontario, Canada