Eco-routing in dense urban networks: evaluating time and emission trade-offs using the COPERT model in Rome

Road transport emissions significantly contribute to urban air pollution, necessitating effective strategies to mitigate their environmental impact. Traditional routing typically optimizes travel time or distance, neglecting emission considerations. This paper proposes an eco-routing approach integrating emission calculations as a cost factor into path selection. Emissions for each road segment are estimated using the COPERT model, and Dijkstra’s algorithm is applied to compute three routing scenarios: (1) shortest travel-time path, (2) lowest-emission path, and (3) a balanced path integrating both travel time and emissions through monetary valuation. Results indicate that optimizing for the shortest travel time does not consistently yield the most environmentally friendly path. Specifically, routing based on lowest emissions achieved approximately a 29.78% reduction in emissions compared to the fastest path, although it increased average travel time by 19.86%. These findings underscore the importance and effectiveness of incorporating emission factors into routing decisions, highlighting their potential to significantly enhance sustainable transportation planning and urban air quality improvement.