Mobility conveys various benefits, including access to employment, goods and social activities. The paradoxical relation between mobility and its costs is based on the premise that the benefits are derived by the users of transport systems (e.g. drivers) and that the costs are in part assumed by the society and the environment. The demand for mobility has been increasing on par with global economic growth, particularly in developing economies in recent years. Motorization has been a prevalent trend, which has increased the footprint of transportation infrastructures such as roads, terminals and vehicles. This mobility also consumes vast quantities of energy, with petroleum being the main source.
Mobility comes at a cost partially assumed by the users (e.g. fuel, maintenance, licensing, insurance, etc.). However, there are societal costs mainly involving infrastructure provision and maintenance as well as accidents related to the operation of transport systems. Environmental costs mostly assumed by the society can be linked with pollutant emissions, such as volatile organic compounds and carbon. The benefits of mobility are internal to the users while the costs are, in part, externalized. The assessment and measurement of externalities remain one of the most salient environmental concerns.