Why is it critical to address transportation affordability?
In 2008, the UN estimated that for the first time in history, half of the world’s population lived in an urban setting, threshold that is believed to reach two thirds in 2050. These urbanization trends have been accompanied by a global domination of car culture, with the environmental impacts that we know. Need for sustainable transportation has been generalized at the global developed scale to fight pollution, sprawl and obesity but also in local contexts for better access to health, education. It is estimated that 40-60% of people in developing countries live more than 8 km from a health care facility.
Transportation affordability/sustainability
Transportation affordability is inscribed as economic dimension into larger dynamics of sustainability (environmental and social), expressed as sustainability’s Triple Bottom Line (Elkington, 1994) Affordability is therefore primarily economic, if people can pay handle transportation cost, but is also linked to environmental and social issues
It is hard to pinpoint an empirical threshold that defines affordability of transportation as it depends on the individual situation and development levels, however the rule of thumb has been identified as 20% of income spent on transportation. For practical purposes across the following case studies, transportation affordability will be addressed in terms of magnitude of use and estimation of how well transportation systems match the population’s needs.
Transicity 