The use of modal accessibility gap as an indicator for sustainable transport development

Transport plays an important role in sustainable development because much energy is used on transport. There is a need to develop indicators for assessing and monitoring sustainable transport development. The paper is to develop a sustainable transport development indicator by making use the concept of accessibility and geographical information system (GIS).. A modal accessibility gap index is proposed to measure and monitor sustainable transport development by GIS. It is calculated by finding the difference between accessibility to opportunities such as the number of population, jobs, shops and schools by public and private transport. The accessibility gap is calculated by finding the difference between the accessibility indexes of public and private transport. With the concern of energy-efficient transport, public transport will achieve sustainable transport more than private transport. A higher accessibility gap may mean more sustainable development. The accessibility gap of 1991 is compared with that of 1996 to see whether transport development is more sustainable or not. The paper will also discuss how to use the accessibility gap indicator to test different land-use and transport development policies and scenarios to see which one will be more sustainable than the others.