Systematic framework for sustainable urban road alignment planning

Sustainable urban road alignment planning should provide functional, economical, people-friendly, and eco-friendly schemes to meet traffic-related demands and promote social develop-ment. However, how to realise it is unclear. This research systematically develops a framework for it from the perspective of factors that should be considered, digitalisation and parsing methods, factor evaluation, and road alignment generation based on a systematic literature re-view, two rounds of questionnaire surveys using the Delphi method, three focus groups, and questionnaire surveys for multi-criteria decision making (MCDM). The considered factors are determined, including traffic, development, cost, social, environmental, and engineering factors. Several digitalisation and parsing methods for the factors are proposed, including direct assign-ment methods, spatial analysis methods, complex professional analysis methods, and other methods. The MCDM-GIS (geographic information system) method using the least-cost wide path analysis is suggested for road alignment generation. The importance of the factors is evaluated by the experts using MCDM.