Transport accessibility and social inequities: a tool for identification of mobility needs and evaluation of transport investments

摘要

Although the concept of social equity seems to be ubiquitous in most mobility plans of major Latin American cities, when evaluating transport projects for financing and prioritisation there are no specific or solid indicators to measure how they can contribute to promoting better access to opportunities, particularly for the most vulnerable segments of the population. In response, we designed a methodology that uses the concepts of accessibility and affordability as a complementary means for evaluating public transport investment, and identifying transport disadvantages and priorities for project generation. This is based on the calculation of accessibility levels to the labour market for different zones of a given city, by introducing a function of impedance composed by travel time budget and the percentage of income spent on transportation.The characteristics of time and percentage of income spent for accessing work obtained from transportation surveys define the "real accessibility" to employment for all the zones of a city. Then, a stated preference survey was applied in order to determine the desired expenditure in both variables, and the accessibility to jobs in this new situation was subsequently calculated. We calculated a third type of accessibility, using "standard" values of travel time and expenditure budget.This methodology is therefore used to evaluate different policies in Bogota, corresponding to changes in the fare structure of the existing public transport system, by proposing the development of cross subsidies, and carrying out an appraised on the impact of the development of a new Bus Rapid Transit line. The results show that depending on the population, its location and purchasing power, the impact of a redis-tributive fare with respect to accessibility to the labour market can be greater than the expansion and improvement of the public transport network.