Incorporating equity in multi-objective optimal spatial budget allocation of transit services by tessellating the urban continuum

Transit systems, similarly to cities, can be conceived as living and evolving ‘organisms’ with ever-changing characteristics. Moreover, transit systems are considered the backbone of today’s urban mobility ecosystem and part of a sustainable mobility paradigm. However, in many cases, existing transit systems have not successfully adapted to the prevailing socio-demographic context nor incorporated available technological means. As so, redesigning an effective transit system is a tedious task, and although sustainability objectives have recently been considered in a wide scope, aiming to incorporate multiple concerns in urban transport planning (sometimes just declaratively), elements of transport fairness and equity are often overlooked in the process. This paper proposes a novel holistic framework for optimally planning a realistic transit system that ensures fairness and transport equity for users at the strategic level. The framework is comprised of three main parts: (i) assessing the current sustainability performance of the transit service and infrastructure by tessellating the urban continuum into the distinctive constituent districts, (ii) sustainability, fairness and equity indicators for each district are fitted into closed-form equations useful for formulating a realistic (though strategic) spatial budget allocation process, and (iii) solving a multi-objective optimization, revealing trade-offs among indicators of sustainability, fairness and equity in transit system development, addressed by a multi-objective particle swarm routine. The study is showcased for the case of Cyprus’ capital, the city of Nicosia, whose bus public transport system is currently being reconsidered, providing solid evidence on the applicability of the proposed novel analytical framework on large-scale urban conglomerations.