Optimizing Urban Road Networks: A Systematic Review of Design, Control and Multimodal Integration

Abstract

Urban areas worldwide are grappling with the pervasive challenge of traffic congestion, which impedes economic productivity, degrades environmental quality, and diminishes the quality of life for residents. The design and management of road networks are fundamental determinants of urban mobility. This systematic review presents a comprehensive analysis and proposes a new conceptual framework for optimizing road networks to enhance traffic flow. The critical interdependencies between network topology, smart traffic management systems, and multimodal integration are examined. Through a structured review of 82 selected studies, this paper synthesizes the evidence on various interventions, from hierarchical network forms to adaptive traffic control and Bus Rapid Transit (BRT). Case studies from Singapore, Curitiba, and Amsterdam illustrate that success is contingent not only on technical solutions but also on specific governance models. The review highlights the powerful synergy between physical infrastructure and intelligent control systems, but also identifies an emerging conflict between centralized planning and decentralized, user-led optimization through modern navigation applications. We conclude that moving beyond isolated fixes requires an integrated decision-making framework that acknowledges these complex interactions. This paper provides a comprehensive resource for researchers, transportation engineers, and urban planners seeking to develop more efficient, sustainable, and resilient urban transportation systems.