iGREEN: An Integrated Emission Model for Mixed Bus Fleets

Abstract

The environmental concern has become central for many bus companies, but estimating pollutant emissions can be difficult for many reasons (little knowledge or underestimation of the problem; scarce know-how; reluctance to acknowledge the pollutant potential of bus fleets because either of small size or composed by too many old-generation vehicles). To facilitate this task, an integrated, user-friendly model, iGREEN, is presented. The paper describes the methodology for the development of this tool, which is specifically designed to help transit operators in assessing the pollutants emitted by fleets where the amount of old buses is not negligible. This is not a minor issue, given the large number of obsolete vehicles still circulating and the unsuitability of some models when calculating emissions in case of buses with protracted mileage. Results from two case studies are reported and commented, with the final aim to advance knowledge farther afield. This gives rise to a discussion on the relevance of such environmental concerns also in light of the contemporary pandemic which seem to have generated different priorities in the public transport management.

Study on the Emission Characteristics of Typical City Buses under Actual Road Conditions

“…Furthermore, in order to better evaluate the pollutant emissions from vehicles, Maria Vittoria Corazza [36] proposed the iGreen model, and Zhuoqun Sun [37] proposed long short-term memory (LSTM) network-based emission models to evaluate the CO, CO 2 , HC, and NOx emissions from buses. On the basis of LSTM, Guo Jinquan [38] added pattern recognition, and the prediction effect of the low-speed driving cycle of urban buses was improved to some extent.…”