Transportation systems are linked with a wide range of environmental considerations from the global to the local. Environmental impacts are related to transport modes, their energy supply systems, their emissions, and the infrastructures over which they operate. While consuming large quantities of energy, especially oil, vehicles also emit numerous pollutants such as carbon dioxide, nitrogen oxide, and noise, and transport infrastructures have damaged many ecological systems. Several of the environmental impacts of transport systems have been externalized, implying that a few realize the benefits of mobility while the whole society assumes the costs. The spatial structure of economic activities, notably their land use, is also increasingly linked with environmental impacts. The sustainability of transport systems has become one core issue in the provision of mobility, particularly decarbonization.