Environmental sustainability of urban road transport: an integrated analysis for life cycle emission impact

Despite of significant contributions of urban road transport to global economy and society, it is one of the largest sources of local and global emission impact. In order to address the environmental concerns of urban road transport it is imperative to achieve a holistic understanding of contributory factors causing emissions, which requires a complete look onto its whole life cycle. Previous studies were mainly based on segmental views, which mostly studied environmental impacts of individual transport modes and very few considered impacts other than operational phase. This study develops an integrated life cycle inventory model for urban road transport emissions from a holistic modal perspective. The Singapore case was used to demonstrate the model. Results show that total life cycle greenhouse gas emission from Singapore's road transport sector is 7.8 million tons per year. The total amount of criteria air pollutants are also estimated in this study.