Review and Classification of Objectives in Dynamic Dial-a-Ride Systems: A Triple Bottom Line Approach of Sustainability

Abstract

Dynamic dial-a-ride problems (DDARPs) involve designing routes and schedules for customers with specific origins and destinations. While the optimization of DDARPs has been extensively examined, these analyses often focus solely on economic decisions. The recent literature emphasizes the inclusion of social and environmental factors in addition to economic considerations for a sustainable transportation system. This paper provides a conceptual review that identifies and classifies the most common DDARP objectives in the three dimensions of the Triple-Bottom-Line (3BL) approach of sustainability: environmental, economic, and social. This study analyzes the interconnections among different objectives and provides insights into multi-objective approaches used in transportation problems. The findings demonstrate the interconnectedness of objectives from different dimensions and highlight the involvement of various stakeholders in decision-making. The results show that optimizing one objective may have implications for other objectives, suggesting a trade-off to be considered. The results reveal that social objectives boost the economic dimension by improving service quality; however, environmental objectives negatively impact the economic dimension. Additionally, a geographical analysis was conducted, which revealed continent-wise variations in research focus and contributions. Future studies should focus more on the social and environmental dimensions to promote a sustainable transportation system.