A Geometry-First, Phased Framework for Solving Intersection Congestion in Mixed-Traffic Megacities

Road congestion in Dhaka has evolved into a structural and systemic crisis, imposing substantial economic losses, safety risks, and environmental degradation. Empirical observation indicates that congestion at major urban intersections is not primarily driven by inadequate roadway width or demand alone, but by intersection-level operational and geometric failures. These failures include unregulated bus stopping at junction approaches, heterogeneous traffic mixing with extreme speed differentials, uncontrolled turning and U-turn movements, unsafe pedestrian crossing behavior, and insufficient geometric guidance to stabilize traffic streams. This research develops and applies a scientifically grounded, phased (A–B–C) intervention framework for congestion mitigation at high-conflict urban intersections under mixed-traffic conditions. Phase A (0–6 months) focuses on rapid operational unlocking through low-cost measures such as bus stop relocation, lane channelization, U-turn control, pedestrian fencing, and enforcement-supported traffic discipline. Phase B (6–24 months) introduces permanent geometric self-enforcement through channelized intersection layouts, raised islands, dedicated bus bays, turbo-roundabout principles, and targeted pedestrian grade separation. Phase C (2–5 years) provides long-term reliability through selective grade separation of dominant traffic corridors combined with surface-level access management and multimodal integration. The framework is applied to two representative and contrasting junction typologies in Dhaka: Kawran Bazar Mor, a market-dominated, bus-intensive intersection primarily affected by stopping and mixing conflicts; and Bijoy Sarani Mor, a high-speed arterial junction where congestion is driven by lane weaving, shock braking, and flow instability. Using field-based diagnostic logic, conflict-point analysis, before–after performance indicators, and internationally recognized geometric design principles adapted to Dhaka’s heterogeneous traffic environment, the study demonstrates that geometry-first, phased interventions can reduce intersection delay and congestion by approximately 30–70%, while reducing conflict points by more than 50%, without immediate reliance on large-scale flyovers or expressway construction. The results establish that effective congestion mitigation in Dhaka requires prioritizing intersection discipline, geometric control, and multimodal separation over signal intensification or road widening. The proposed framework is technically robust, cost-effective, scalable, and institutionally feasible, making it suitable for citywide implementation in Dhaka and transferable to other high-density megacities in South Asia and the Global South. Please check the attachment for details